diff --git a/.eslintrc b/.eslintrc
index 76c42539c061c..90770468d6db1 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -2,6 +2,5 @@
 extends: '@elastic/kibana'
 rules:
   no-unused-vars: off
-  prefer-const: off
   no-extra-semi: off
   quotes: off
diff --git a/src/cli/cluster/worker.js b/src/cli/cluster/worker.js
index 4108627edea65..320defcb7e0d5 100644
--- a/src/cli/cluster/worker.js
+++ b/src/cli/cluster/worker.js
@@ -5,16 +5,16 @@ import { EventEmitter } from 'events';
 
 import { BinderFor, fromRoot } from '../../utils';
 
-let cliPath = fromRoot('src/cli');
-let baseArgs = _.difference(process.argv.slice(2), ['--no-watch']);
-let baseArgv = [process.execPath, cliPath].concat(baseArgs);
+const cliPath = fromRoot('src/cli');
+const baseArgs = _.difference(process.argv.slice(2), ['--no-watch']);
+const baseArgv = [process.execPath, cliPath].concat(baseArgs);
 
 cluster.setupMaster({
   exec: cliPath,
   silent: false
 });
 
-let dead = fork => {
+const dead = fork => {
   return fork.isDead() || fork.killed;
 };
 
@@ -40,7 +40,7 @@ module.exports = class Worker extends EventEmitter {
     this.clusterBinder = new BinderFor(cluster);
     this.processBinder = new BinderFor(process);
 
-    let argv = _.union(baseArgv, opts.argv || []);
+    const argv = _.union(baseArgv, opts.argv || []);
     this.env = {
       kbnWorkerType: this.type,
       kbnWorkerArgv: JSON.stringify(argv)
@@ -124,8 +124,8 @@ module.exports = class Worker extends EventEmitter {
   }
 
   flushChangeBuffer() {
-    let files = _.unique(this.changes.splice(0));
-    let prefix = files.length > 1 ? '\n - ' : '';
+    const files = _.unique(this.changes.splice(0));
+    const prefix = files.length > 1 ? '\n - ' : '';
     return files.reduce(function (list, file) {
       return `${list || ''}${prefix}"${file}"`;
     }, '');
diff --git a/src/cli/command.js b/src/cli/command.js
index 135d03e32b6c1..98997f4bc1100 100644
--- a/src/cli/command.js
+++ b/src/cli/command.js
@@ -40,15 +40,15 @@ Command.prototype.unknownArgv = function (argv) {
  * @return {[type]} [description]
  */
 Command.prototype.collectUnknownOptions = function () {
-  let title = `Extra ${this._name} options`;
+  const title = `Extra ${this._name} options`;
 
   this.allowUnknownOption();
   this.getUnknownOptions = function () {
-    let opts = {};
-    let unknowns = this.unknownArgv();
+    const opts = {};
+    const unknowns = this.unknownArgv();
 
     while (unknowns.length) {
-      let opt = unknowns.shift().split('=');
+      const opt = unknowns.shift().split('=');
       if (opt[0].slice(0, 2) !== '--') {
         this.error(`${title} "${opt[0]}" must start with "--"`);
       }
@@ -75,14 +75,14 @@ Command.prototype.collectUnknownOptions = function () {
 };
 
 Command.prototype.parseOptions = _.wrap(Command.prototype.parseOptions, function (parse, argv) {
-  let opts = parse.call(this, argv);
+  const opts = parse.call(this, argv);
   this.unknownArgv(opts.unknown);
   return opts;
 });
 
 Command.prototype.action = _.wrap(Command.prototype.action, function (action, fn) {
   return action.call(this, function (...args) {
-    let ret = fn.apply(this, args);
+    const ret = fn.apply(this, args);
     if (ret && typeof ret.then === 'function') {
       ret.then(null, function (e) {
         console.log('FATAL CLI ERROR', e.stack);
diff --git a/src/cli/help.js b/src/cli/help.js
index 89bc90a24cbd6..b5078aad458fe 100644
--- a/src/cli/help.js
+++ b/src/cli/help.js
@@ -5,12 +5,12 @@ module.exports = function (command, spaces) {
     return command.outputHelp();
   }
 
-  let defCmd = _.find(command.commands, function (cmd) {
+  const defCmd = _.find(command.commands, function (cmd) {
     return cmd._name === 'serve';
   });
 
-  let desc = !command.description() ? '' : command.description();
-  let cmdDef = !defCmd ? '' : `=${defCmd._name}`;
+  const desc = !command.description() ? '' : command.description();
+  const cmdDef = !defCmd ? '' : `=${defCmd._name}`;
 
   return (
 `
@@ -31,11 +31,11 @@ function indent(str, n) {
 }
 
 function commandsSummary(program) {
-  let cmds = _.compact(program.commands.map(function (cmd) {
-    let name = cmd._name;
+  const cmds = _.compact(program.commands.map(function (cmd) {
+    const name = cmd._name;
     if (name === '*') return;
-    let opts = cmd.options.length ? ' [options]' : '';
-    let args = cmd._args.map(function (arg) {
+    const opts = cmd.options.length ? ' [options]' : '';
+    const args = cmd._args.map(function (arg) {
       return humanReadableArgName(arg);
     }).join(' ');
 
@@ -45,7 +45,7 @@ function commandsSummary(program) {
     ];
   }));
 
-  let cmdLColWidth = cmds.reduce(function (width, cmd) {
+  const cmdLColWidth = cmds.reduce(function (width, cmd) {
     return Math.max(width, cmd[0].length);
   }, 0);
 
@@ -69,6 +69,6 @@ ${indent(cmd.optionHelp(), 2)}
 }
 
 function humanReadableArgName(arg) {
-  let nameOutput = arg.name + (arg.variadic === true ? '...' : '');
+  const nameOutput = arg.name + (arg.variadic === true ? '...' : '');
   return arg.required ? '<' + nameOutput + '>' : '[' + nameOutput + ']';
 }
diff --git a/src/cli/log.js b/src/cli/log.js
index bbbe3f2f21e89..50657ca533028 100644
--- a/src/cli/log.js
+++ b/src/cli/log.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import ansicolors from 'ansicolors';
 
-let log = _.restParam(function (color, label, rest1) {
+const log = _.restParam(function (color, label, rest1) {
   console.log.apply(console, [color(` ${_.trim(label)} `)].concat(rest1));
 });
 
diff --git a/src/cli_plugin/cli.js b/src/cli_plugin/cli.js
index 5a09416a9cb1a..3ff2ba328830f 100644
--- a/src/cli_plugin/cli.js
+++ b/src/cli_plugin/cli.js
@@ -5,8 +5,8 @@ import listCommand from './list';
 import installCommand from './install';
 import removeCommand from './remove';
 
-let argv = process.env.kbnWorkerArgv ? JSON.parse(process.env.kbnWorkerArgv) : process.argv.slice();
-let program = new Command('bin/kibana-plugin');
+const argv = process.env.kbnWorkerArgv ? JSON.parse(process.env.kbnWorkerArgv) : process.argv.slice();
+const program = new Command('bin/kibana-plugin');
 
 program
 .version(pkg.version)
@@ -23,7 +23,7 @@ program
 .command('help <command>')
 .description('get the help for a specific command')
 .action(function (cmdName) {
-  let cmd = _.find(program.commands, { _name: cmdName });
+  const cmd = _.find(program.commands, { _name: cmdName });
   if (!cmd) return program.error(`unknown command ${cmdName}`);
   cmd.help();
 });
@@ -35,7 +35,7 @@ program
 });
 
 // check for no command name
-let subCommand = argv[2] && !String(argv[2][0]).match(/^-|^\.|\//);
+const subCommand = argv[2] && !String(argv[2][0]).match(/^-|^\.|\//);
 if (!subCommand) {
   program.defaultHelp();
 }
diff --git a/src/cli_plugin/install/__tests__/index.js b/src/cli_plugin/install/__tests__/index.js
index 470d9452a1c12..701247a49492e 100644
--- a/src/cli_plugin/install/__tests__/index.js
+++ b/src/cli_plugin/install/__tests__/index.js
@@ -8,7 +8,7 @@ describe('kibana cli', function () {
 
     describe('commander options', function () {
 
-      let program = {
+      const program = {
         command: function () { return program; },
         description: function () { return program; },
         option: function () { return program; },
diff --git a/src/cli_plugin/install/downloaders/file.js b/src/cli_plugin/install/downloaders/file.js
index 505a103755e66..bd8233c009614 100644
--- a/src/cli_plugin/install/downloaders/file.js
+++ b/src/cli_plugin/install/downloaders/file.js
@@ -3,7 +3,7 @@ import { createWriteStream, createReadStream, unlinkSync, statSync } from 'fs';
 
 function openSourceFile({ sourcePath }) {
   try {
-    let fileInfo = statSync(sourcePath);
+    const fileInfo = statSync(sourcePath);
 
     const readStream = createReadStream(sourcePath);
 
diff --git a/src/cli_plugin/install/downloaders/http.js b/src/cli_plugin/install/downloaders/http.js
index 40069c4cd063e..0b9844a6d9c14 100644
--- a/src/cli_plugin/install/downloaders/http.js
+++ b/src/cli_plugin/install/downloaders/http.js
@@ -53,7 +53,7 @@ export default async function downloadUrl(logger, sourceUrl, targetPath, timeout
     const { req, resp } = await sendRequest({ sourceUrl, timeout });
 
     try {
-      let totalSize = parseFloat(resp.headers['content-length']) || 0;
+      const totalSize = parseFloat(resp.headers['content-length']) || 0;
       const progress = new Progress(logger);
       progress.init(totalSize);
 
diff --git a/src/core_plugins/elasticsearch/lib/__tests__/is_upgradeable.js b/src/core_plugins/elasticsearch/lib/__tests__/is_upgradeable.js
index 0e9b064393d15..7ab961a81a0ab 100644
--- a/src/core_plugins/elasticsearch/lib/__tests__/is_upgradeable.js
+++ b/src/core_plugins/elasticsearch/lib/__tests__/is_upgradeable.js
@@ -8,7 +8,7 @@ let version = pkg.version;
 
 describe('plugins/elasticsearch', function () {
   describe('lib/is_upgradeable', function () {
-    let server = {
+    const server = {
       config: _.constant({
         get: function (key) {
           switch (key) {
@@ -44,7 +44,7 @@ describe('plugins/elasticsearch', function () {
     upgradeDoc('5.0.0-alpha1', '5.0.0', false);
 
     it('should handle missing _id field', function () {
-      let doc = {
+      const doc = {
         '_index': '.kibana',
         '_type': 'config',
         '_score': 1,
@@ -58,7 +58,7 @@ describe('plugins/elasticsearch', function () {
     });
 
     it('should handle _id of @@version', function () {
-      let doc = {
+      const doc = {
         '_index': '.kibana',
         '_type': 'config',
         '_id': '@@version',
diff --git a/src/core_plugins/kbn_doc_views/public/views/table.js b/src/core_plugins/kbn_doc_views/public/views/table.js
index af201f39c3539..fef633e5827ec 100644
--- a/src/core_plugins/kbn_doc_views/public/views/table.js
+++ b/src/core_plugins/kbn_doc_views/public/views/table.js
@@ -26,7 +26,7 @@ docViewsRegistry.register(function () {
         };
 
         $scope.showArrayInObjectsWarning = function (row, field) {
-          let value = $scope.flattened[field];
+          const value = $scope.flattened[field];
           return _.isArray(value) && typeof value[0] === 'object';
         };
       }
diff --git a/src/core_plugins/kibana/index.js b/src/core_plugins/kibana/index.js
index 6b22f5271fb0a..b31e32d3dd7fd 100644
--- a/src/core_plugins/kibana/index.js
+++ b/src/core_plugins/kibana/index.js
@@ -30,7 +30,7 @@ module.exports = function (kibana) {
         ],
 
         injectVars: function (server, options) {
-          let config = server.config();
+          const config = server.config();
           return {
             kbnDefaultAppId: config.get('kibana.defaultAppId'),
             tilemap: config.get('tilemap')
diff --git a/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/directives/output_preview.js b/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/directives/output_preview.js
index 8135fca9e1b4a..be9ecea4d89b3 100644
--- a/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/directives/output_preview.js
+++ b/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/directives/output_preview.js
@@ -28,8 +28,8 @@ app.directive('outputPreview', function () {
       });
 
       $scope.updateUi = function () {
-        let left = $scope.oldObject;
-        let right = $scope.newObject;
+        const left = $scope.oldObject;
+        const right = $scope.newObject;
         let delta = $scope.diffpatch.diff(left, right);
         if (!delta || $scope.error) delta = {};
 
diff --git a/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/__tests__/keys_deep.js b/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/__tests__/keys_deep.js
index 05f06927a4351..8995042138230 100644
--- a/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/__tests__/keys_deep.js
+++ b/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/__tests__/keys_deep.js
@@ -5,11 +5,11 @@ import keysDeep from '../keys_deep';
 describe('keys deep', function () {
 
   it('should list first level properties', function () {
-    let object = {
+    const object = {
       property1: 'value1',
       property2: 'value2'
     };
-    let expected = [
+    const expected = [
       'property1',
       'property2'
     ];
@@ -20,14 +20,14 @@ describe('keys deep', function () {
   });
 
   it('should list nested properties', function () {
-    let object = {
+    const object = {
       property1: 'value1',
       property2: 'value2',
       property3: {
         subProperty1: 'value1.1'
       }
     };
-    let expected = [
+    const expected = [
       'property1',
       'property2',
       'property3.subProperty1',
@@ -40,7 +40,7 @@ describe('keys deep', function () {
   });
 
   it('should recursivly list nested properties', function () {
-    let object = {
+    const object = {
       property1: 'value1',
       property2: 'value2',
       property3: {
@@ -52,7 +52,7 @@ describe('keys deep', function () {
         subProperty3: 'value1.3'
       }
     };
-    let expected = [
+    const expected = [
       'property1',
       'property2',
       'property3.subProperty1',
@@ -69,11 +69,11 @@ describe('keys deep', function () {
   });
 
   it('should list array properties, but not contents', function () {
-    let object = {
+    const object = {
       property1: 'value1',
       property2: [ 'item1', 'item2' ]
     };
-    let expected = [
+    const expected = [
       'property1',
       'property2'
     ];
diff --git a/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/keys_deep.js b/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/keys_deep.js
index 5b5976583f132..a1f26d224dbc8 100644
--- a/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/keys_deep.js
+++ b/src/core_plugins/kibana/public/management/sections/indices/add_data_steps/pipeline_setup/lib/keys_deep.js
@@ -2,10 +2,10 @@ import _ from 'lodash';
 
 export default function keysDeep(object, base) {
   let result = [];
-  let delimitedBase = base ? base + '.' : '';
+  const delimitedBase = base ? base + '.' : '';
 
   _.forEach(object, (value, key) => {
-    let fullKey = delimitedBase + key;
+    const fullKey = delimitedBase + key;
     if (_.isPlainObject(value)) {
       result = result.concat(keysDeep(value, fullKey));
     } else {
diff --git a/src/core_plugins/kibana/public/management/sections/indices/filebeat/directives/filebeat_wizard.js b/src/core_plugins/kibana/public/management/sections/indices/filebeat/directives/filebeat_wizard.js
index fa2967f8cebc3..677de52e740d9 100644
--- a/src/core_plugins/kibana/public/management/sections/indices/filebeat/directives/filebeat_wizard.js
+++ b/src/core_plugins/kibana/public/management/sections/indices/filebeat/directives/filebeat_wizard.js
@@ -20,11 +20,11 @@ modules.get('apps/management')
       const ingest = Private(IngestProvider);
       const $state = this.state = new AppState();
 
-      let notify = new Notifier({
+      const notify = new Notifier({
         location: 'Add Data'
       });
 
-      let totalSteps = 4;
+      const totalSteps = 4;
       this.stepResults = {};
 
       this.setCurrentStep = (step) => {
diff --git a/src/core_plugins/kibana/public/management/sections/indices/upload/directives/upload_wizard.js b/src/core_plugins/kibana/public/management/sections/indices/upload/directives/upload_wizard.js
index 92c79fe01d152..31f0888cb5aba 100644
--- a/src/core_plugins/kibana/public/management/sections/indices/upload/directives/upload_wizard.js
+++ b/src/core_plugins/kibana/public/management/sections/indices/upload/directives/upload_wizard.js
@@ -19,11 +19,11 @@ modules.get('apps/management')
         const ingest = Private(IngestProvider);
         const $state = this.state = new AppState();
 
-        let notify = new Notifier({
+        const notify = new Notifier({
           location: 'Add Data'
         });
 
-        let totalSteps = 3;
+        const totalSteps = 3;
         this.stepResults = {};
 
         this.setCurrentStep = (step) => {
diff --git a/src/core_plugins/kibana/server/lib/__tests__/create_mappings_from_pattern_fields.js b/src/core_plugins/kibana/server/lib/__tests__/create_mappings_from_pattern_fields.js
index 7444d38384638..6d83ee73f7645 100644
--- a/src/core_plugins/kibana/server/lib/__tests__/create_mappings_from_pattern_fields.js
+++ b/src/core_plugins/kibana/server/lib/__tests__/create_mappings_from_pattern_fields.js
@@ -36,7 +36,7 @@ describe('createMappingsFromPatternFields', function () {
   });
 
   it('should set the same default mapping for all non-strings', function () {
-    let mappings = createMappingsFromPatternFields(testFields);
+    const mappings = createMappingsFromPatternFields(testFields);
 
     _.forEach(mappings, function (mapping) {
       if (mapping.type !== 'text') {
@@ -50,7 +50,7 @@ describe('createMappingsFromPatternFields', function () {
   });
 
   it('should give strings a multi-field mapping with a "text" base type', function () {
-    let mappings = createMappingsFromPatternFields(testFields);
+    const mappings = createMappingsFromPatternFields(testFields);
 
     _.forEach(mappings, function (mapping) {
       if (mapping.type === 'text') {
@@ -61,7 +61,7 @@ describe('createMappingsFromPatternFields', function () {
 
   it('should handle nested fields', function () {
     testFields.push({name: 'geo.coordinates', type: 'geo_point'});
-    let mappings = createMappingsFromPatternFields(testFields);
+    const mappings = createMappingsFromPatternFields(testFields);
 
     expect(mappings).to.have.property('geo');
     expect(mappings.geo).to.have.property('properties');
@@ -74,7 +74,7 @@ describe('createMappingsFromPatternFields', function () {
   });
 
   it('should map all number fields as an ES double', function () {
-    let mappings = createMappingsFromPatternFields(testFields);
+    const mappings = createMappingsFromPatternFields(testFields);
 
     expect(mappings).to.have.property('bytes');
     expect(mappings.bytes).to.have.property('type', 'double');
diff --git a/src/core_plugins/table_vis/public/table_vis_controller.js b/src/core_plugins/table_vis/public/table_vis_controller.js
index 15e1cc40ed0b1..55ffd881f75e1 100644
--- a/src/core_plugins/table_vis/public/table_vis_controller.js
+++ b/src/core_plugins/table_vis/public/table_vis_controller.js
@@ -11,7 +11,7 @@ const module = uiModules.get('kibana/table_vis', ['kibana']);
 module.controller('KbnTableVisController', function ($scope, Private) {
   const tabifyAggResponse = Private(AggResponseTabifyTabifyProvider);
 
-  let uiStateSort = ($scope.uiState) ? $scope.uiState.get('vis.params.sort') : {};
+  const uiStateSort = ($scope.uiState) ? $scope.uiState.get('vis.params.sort') : {};
   assign($scope.vis.params.sort, uiStateSort);
 
   $scope.sort = $scope.vis.params.sort;
diff --git a/src/core_plugins/tests_bundle/find_source_files.js b/src/core_plugins/tests_bundle/find_source_files.js
index c6b6151166cda..1a2938bbacd5d 100644
--- a/src/core_plugins/tests_bundle/find_source_files.js
+++ b/src/core_plugins/tests_bundle/find_source_files.js
@@ -5,7 +5,7 @@ import { resolve } from 'path';
 import { map, fromNode } from 'bluebird';
 import glob from 'glob-all';
 
-let findSourceFiles = async (patterns, cwd = fromRoot('.')) => {
+const findSourceFiles = async (patterns, cwd = fromRoot('.')) => {
   patterns = [].concat(patterns || []);
 
   const matches = await fromNode(cb => {
diff --git a/src/core_plugins/tests_bundle/index.js b/src/core_plugins/tests_bundle/index.js
index 34fe685e4602b..46f52ca91131b 100644
--- a/src/core_plugins/tests_bundle/index.js
+++ b/src/core_plugins/tests_bundle/index.js
@@ -16,7 +16,7 @@ export default (kibana) => {
     uiExports: {
       bundle: async (UiBundle, env, apps, plugins) => {
         let modules = [];
-        let config = kibana.config;
+        const config = kibana.config;
 
         const testGlobs = ['src/ui/public/**/*.js'];
         const testingPluginIds = config.get('tests_bundle.pluginId');
@@ -28,7 +28,7 @@ export default (kibana) => {
             if (!plugin) throw new Error('Invalid testingPluginId :: unknown plugin ' + pluginId);
 
             // add the modules from all of this plugins apps
-            for (let app of plugin.apps) {
+            for (const app of plugin.apps) {
               modules = union(modules, app.getModules());
             }
 
@@ -37,7 +37,7 @@ export default (kibana) => {
         } else {
 
           // add the modules from all of the apps
-          for (let app of apps) {
+          for (const app of apps) {
             modules = union(modules, app.getModules());
           }
 
@@ -47,7 +47,7 @@ export default (kibana) => {
         }
 
         const testFiles = await findSourceFiles(testGlobs);
-        for (let f of testFiles) modules.push(f);
+        for (const f of testFiles) modules.push(f);
 
         if (config.get('tests_bundle.instrument')) {
           env.addPostLoader({
diff --git a/src/fixtures/agg_resp/geohash_grid.js b/src/fixtures/agg_resp/geohash_grid.js
index 33a446ff360b2..b627b180964c1 100644
--- a/src/fixtures/agg_resp/geohash_grid.js
+++ b/src/fixtures/agg_resp/geohash_grid.js
@@ -17,7 +17,7 @@ export default function GeoHashGridAggResponseFixture() {
   //   },
   // });
 
-  let geoHashCharts = _.union(
+  const geoHashCharts = _.union(
     _.range(48, 57), // 0-9
     _.range(65, 90), // A-Z
     _.range(97, 122) // a-z
@@ -25,15 +25,15 @@ export default function GeoHashGridAggResponseFixture() {
 
   let totalDocCount = 0;
 
-  let tags = _.times(_.random(4, 20), function (i) {
+  const tags = _.times(_.random(4, 20), function (i) {
     // random number of tags
     let docCount = 0;
-    let buckets = _.times(_.random(40, 200), function () {
+    const buckets = _.times(_.random(40, 200), function () {
       return _.sample(geoHashCharts, 3).join('');
     })
     .sort()
     .map(function (geoHash) {
-      let count = _.random(1, 5000);
+      const count = _.random(1, 5000);
 
       totalDocCount += count;
       docCount += count;
diff --git a/src/fixtures/fake_chart_events.js b/src/fixtures/fake_chart_events.js
index 383a61c900815..9e4db976c64e6 100644
--- a/src/fixtures/fake_chart_events.js
+++ b/src/fixtures/fake_chart_events.js
@@ -1,4 +1,4 @@
-let results = {};
+const results = {};
 
 results.timeSeries = {
   data: {
diff --git a/src/fixtures/fake_hierarchical_data.js b/src/fixtures/fake_hierarchical_data.js
index 2b1096cc9c271..d7d734214d4fd 100644
--- a/src/fixtures/fake_hierarchical_data.js
+++ b/src/fixtures/fake_hierarchical_data.js
@@ -1,4 +1,4 @@
-let data = {  };
+const data = {  };
 
 data.metricOnly = {
   hits: { total: 1000, hits: [], max_score: 0 },
diff --git a/src/fixtures/fake_row.js b/src/fixtures/fake_row.js
index 032fe0f1a9235..c7acfd4446774 100644
--- a/src/fixtures/fake_row.js
+++ b/src/fixtures/fake_row.js
@@ -1,5 +1,5 @@
 import _ from 'lodash';
-let longString = Array(200).join('_');
+const longString = Array(200).join('_');
 
 export default function (id, mapping) {
   function fakeVals(type) {
diff --git a/src/fixtures/logstash_fields.js b/src/fixtures/logstash_fields.js
index e4f993da81470..f8e6288cd9751 100644
--- a/src/fixtures/logstash_fields.js
+++ b/src/fixtures/logstash_fields.js
@@ -1,5 +1,5 @@
 function stubbedLogstashFields() {
-  let sourceData = [
+  const sourceData = [
     { name: 'bytes',              type: 'number',     indexed: true,  analyzed: true, sortable:  true,  filterable: true,   count: 10 },
     { name: 'ssl',                type: 'boolean',    indexed: true,  analyzed: true, sortable:  true,  filterable: true,   count: 20 },
     { name: '@timestamp',         type: 'date',       indexed: true,  analyzed: true, sortable:  true,  filterable: true,   count: 30 },
diff --git a/src/fixtures/mock_courier.js b/src/fixtures/mock_courier.js
index ef68696693551..942475fccb4e5 100644
--- a/src/fixtures/mock_courier.js
+++ b/src/fixtures/mock_courier.js
@@ -3,11 +3,11 @@ import sinon from 'auto-release-sinon';
 import FixturesStubbedLogstashIndexPatternProvider from 'fixtures/stubbed_logstash_index_pattern';
 
 export default function (Private, Promise) {
-  let indexPatterns = Private(FixturesStubbedLogstashIndexPatternProvider);
-  let getIndexPatternStub = sinon.stub();
+  const indexPatterns = Private(FixturesStubbedLogstashIndexPatternProvider);
+  const getIndexPatternStub = sinon.stub();
   getIndexPatternStub.returns(Promise.resolve(indexPatterns));
 
-  let courier = {
+  const courier = {
     indexPatterns: { get: getIndexPatternStub },
     getStub: getIndexPatternStub
   };
diff --git a/src/fixtures/mock_ui_state.js b/src/fixtures/mock_ui_state.js
index 5f5b90e38eb3d..7614896cceb6f 100644
--- a/src/fixtures/mock_ui_state.js
+++ b/src/fixtures/mock_ui_state.js
@@ -1,5 +1,5 @@
 import _ from 'lodash';
-let keys = {};
+const keys = {};
 export default {
   get: function (path, def) {
     return keys[path] == null ? def : keys[path];
diff --git a/src/fixtures/stubbed_doc_source_response.js b/src/fixtures/stubbed_doc_source_response.js
index 5bed6d41af348..99055142e5bb1 100644
--- a/src/fixtures/stubbed_doc_source_response.js
+++ b/src/fixtures/stubbed_doc_source_response.js
@@ -1,7 +1,7 @@
 import FixturesLogstashFieldsProvider from 'fixtures/logstash_fields';
 
 function stubbedDocSourceResponse(Private) {
-  let mockLogstashFields = Private(FixturesLogstashFieldsProvider);
+  const mockLogstashFields = Private(FixturesLogstashFieldsProvider);
 
   return function (id, index) {
     index = index || '.kibana';
diff --git a/src/fixtures/stubbed_logstash_index_pattern.js b/src/fixtures/stubbed_logstash_index_pattern.js
index 8377132b6d8ea..daa6b37dc607d 100644
--- a/src/fixtures/stubbed_logstash_index_pattern.js
+++ b/src/fixtures/stubbed_logstash_index_pattern.js
@@ -3,21 +3,21 @@ import TestUtilsStubIndexPatternProvider from 'test_utils/stub_index_pattern';
 import IndexPatternsFieldTypesProvider from 'ui/index_patterns/_field_types';
 import FixturesLogstashFieldsProvider from 'fixtures/logstash_fields';
 export default function stubbedLogstashIndexPatternService(Private) {
-  let StubIndexPattern = Private(TestUtilsStubIndexPatternProvider);
-  let fieldTypes = Private(IndexPatternsFieldTypesProvider);
-  let mockLogstashFields = Private(FixturesLogstashFieldsProvider);
+  const StubIndexPattern = Private(TestUtilsStubIndexPatternProvider);
+  const fieldTypes = Private(IndexPatternsFieldTypesProvider);
+  const mockLogstashFields = Private(FixturesLogstashFieldsProvider);
 
 
-  let fields = mockLogstashFields.map(function (field) {
+  const fields = mockLogstashFields.map(function (field) {
     field.displayName = field.name;
-    let type = fieldTypes.byName[field.type];
+    const type = fieldTypes.byName[field.type];
     if (!type) throw new TypeError('unknown type ' + field.type);
     if (!_.has(field, 'sortable')) field.sortable = type.sortable;
     if (!_.has(field, 'filterable')) field.filterable = type.filterable;
     return field;
   });
 
-  let indexPattern = new StubIndexPattern('logstash-*', 'time', fields);
+  const indexPattern = new StubIndexPattern('logstash-*', 'time', fields);
   indexPattern.id = 'logstash-*';
 
   return indexPattern;
diff --git a/src/fixtures/stubbed_search_source.js b/src/fixtures/stubbed_search_source.js
index 118aaede15047..284a0bf00bbea 100644
--- a/src/fixtures/stubbed_search_source.js
+++ b/src/fixtures/stubbed_search_source.js
@@ -4,7 +4,7 @@ import FixturesStubbedLogstashIndexPatternProvider from 'fixtures/stubbed_logsta
 
 export default function stubSearchSource(Private, $q, Promise) {
   let deferedResult = $q.defer();
-  let indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
+  const indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
 
   return {
     sort: sinon.spy(),
diff --git a/src/fixtures/vislib/_vis_fixture.js b/src/fixtures/vislib/_vis_fixture.js
index 8f06190120053..8fbc2f0f44ac0 100644
--- a/src/fixtures/vislib/_vis_fixture.js
+++ b/src/fixtures/vislib/_vis_fixture.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import $ from 'jquery';
 import VislibVisProvider from 'ui/vislib/vis';
 
-let $visCanvas = $('<div>')
+const $visCanvas = $('<div>')
   .attr('id', 'vislib-vis-fixtures')
   .css({
     height: '500px',
@@ -16,7 +16,7 @@ let $visCanvas = $('<div>')
   .appendTo('body');
 
 let count = 0;
-let visHeight = $visCanvas.height();
+const visHeight = $visCanvas.height();
 
 $visCanvas.new = function () {
   count += 1;
@@ -32,7 +32,7 @@ afterEach(function () {
 
 module.exports = function VislibFixtures(Private) {
   return function (visLibParams) {
-    let Vis = Private(VislibVisProvider);
+    const Vis = Private(VislibVisProvider);
     return new Vis($visCanvas.new(), _.defaults({}, visLibParams || {}, {
       shareYAxis: true,
       addTooltip: true,
diff --git a/src/optimize/babel_options.build.js b/src/optimize/babel_options.build.js
index 885a318ab84d1..ec3f11f6f1528 100644
--- a/src/optimize/babel_options.build.js
+++ b/src/optimize/babel_options.build.js
@@ -1,5 +1,5 @@
 import { cloneDeep } from 'lodash';
-let fromRoot = require('path').resolve.bind(null, __dirname, '../../');
+const fromRoot = require('path').resolve.bind(null, __dirname, '../../');
 
 if (!process.env.BABEL_CACHE_PATH) {
   process.env.BABEL_CACHE_PATH = fromRoot('optimize/.babelcache.json');
diff --git a/src/optimize/babel_options.js b/src/optimize/babel_options.js
index e562700da3708..903701133ae59 100644
--- a/src/optimize/babel_options.js
+++ b/src/optimize/babel_options.js
@@ -1,8 +1,8 @@
 // this file is not transpiled
 'use strict'; // eslint-disable-line strict
 
-let cloneDeep = require('lodash').cloneDeep;
-let fromRoot = require('path').resolve.bind(null, __dirname, '../../');
+const cloneDeep = require('lodash').cloneDeep;
+const fromRoot = require('path').resolve.bind(null, __dirname, '../../');
 
 if (!process.env.BABEL_CACHE_PATH) {
   process.env.BABEL_CACHE_PATH = fromRoot('optimize/.babelcache.json');
diff --git a/src/optimize/base_optimizer.js b/src/optimize/base_optimizer.js
index 5e0e79d3d72a2..66f3117934da3 100644
--- a/src/optimize/base_optimizer.js
+++ b/src/optimize/base_optimizer.js
@@ -12,7 +12,7 @@ import { inherits } from 'util';
 import { defaults, transform } from 'lodash';
 import { resolve } from 'path';
 import { writeFile } from 'fs';
-let babelExclude = [/[\/\\](webpackShims|node_modules|bower_components)[\/\\]/];
+const babelExclude = [/[\/\\](webpackShims|node_modules|bower_components)[\/\\]/];
 import pkg from '../../package.json';
 
 class BaseOptimizer {
@@ -47,14 +47,14 @@ class BaseOptimizer {
   async initCompiler() {
     if (this.compiler) return this.compiler;
 
-    let compilerConfig = this.getConfig();
+    const compilerConfig = this.getConfig();
     this.compiler = webpack(compilerConfig);
 
     this.compiler.plugin('done', stats => {
       if (!this.profile) return;
 
-      let path = resolve(this.env.workingDir, 'stats.json');
-      let content = JSON.stringify(stats.toJson());
+      const path = resolve(this.env.workingDir, 'stats.json');
+      const content = JSON.stringify(stats.toJson());
       writeFile(path, content, function (err) {
         if (err) throw err;
       });
@@ -64,8 +64,8 @@ class BaseOptimizer {
   }
 
   getConfig() {
-    let mapQ = this.sourceMaps ? '?sourceMap' : '';
-    let mapQPre = mapQ ? mapQ + '&' : '?';
+    const mapQ = this.sourceMaps ? '?sourceMap' : '';
+    const mapQPre = mapQ ? mapQ + '&' : '?';
 
     return {
       context: fromRoot('.'),
@@ -177,7 +177,7 @@ class BaseOptimizer {
   }
 
   failedStatsToError(stats) {
-    let statFormatOpts = {
+    const statFormatOpts = {
       hash: false,  // add the hash of the compilation
       version: false,  // add webpack version information
       timings: false,  // add timing information
@@ -196,7 +196,7 @@ class BaseOptimizer {
       children: false,
     };
 
-    let details = stats.toString(defaults({ colors: true }, statFormatOpts));
+    const details = stats.toString(defaults({ colors: true }, statFormatOpts));
 
     return Boom.create(
       500,
diff --git a/src/optimize/fs_optimizer.js b/src/optimize/fs_optimizer.js
index 67e03c66c64a8..3e11b34acaed1 100644
--- a/src/optimize/fs_optimizer.js
+++ b/src/optimize/fs_optimizer.js
@@ -12,7 +12,7 @@ module.exports = class FsOptimizer extends BaseOptimizer {
   async run() {
     if (!this.compiler) await this.init();
 
-    let stats = await fromNode(cb => {
+    const stats = await fromNode(cb => {
       this.compiler.run((err, stats) => {
         if (err || !stats) return cb(err);
 
diff --git a/src/optimize/index.js b/src/optimize/index.js
index a753ea40f8381..fa0028ffe4204 100644
--- a/src/optimize/index.js
+++ b/src/optimize/index.js
@@ -10,17 +10,17 @@ module.exports = async (kbnServer, server, config) => {
   // on the watch setup managed by the cli. It proxies all bundles/* requests to
   // the other server. The server on 5602 is long running, in order to prevent
   // complete rebuilds of the optimize content.
-  let lazy = config.get('optimize.lazy');
+  const lazy = config.get('optimize.lazy');
   if (lazy) {
     return await kbnServer.mixin(require('./lazy/lazy'));
   }
 
-  let bundles = kbnServer.bundles;
+  const bundles = kbnServer.bundles;
   server.exposeStaticDir('/bundles/{path*}', bundles.env.workingDir);
   await bundles.writeEntryFiles();
 
   // in prod, only bundle when someing is missing or invalid
-  let invalidBundles = config.get('optimize.useBundleCache') ? await bundles.getInvalidBundles() : bundles;
+  const invalidBundles = config.get('optimize.useBundleCache') ? await bundles.getInvalidBundles() : bundles;
 
   // we might not have any work to do
   if (!invalidBundles.getIds().length) {
@@ -32,7 +32,7 @@ module.exports = async (kbnServer, server, config) => {
   }
 
   // only require the FsOptimizer when we need to
-  let optimizer = new FsOptimizer({
+  const optimizer = new FsOptimizer({
     env: bundles.env,
     bundles: bundles,
     profile: config.get('optimize.profile'),
@@ -46,9 +46,9 @@ module.exports = async (kbnServer, server, config) => {
     `Optimizing and caching ${bundles.desc()}. This may take a few minutes`
   );
 
-  let start = Date.now();
+  const start = Date.now();
   await optimizer.run();
-  let seconds = ((Date.now() - start) / 1000).toFixed(2);
+  const seconds = ((Date.now() - start) / 1000).toFixed(2);
 
   server.log(['info', 'optimize'], `Optimization of ${bundles.desc()} complete in ${seconds} seconds`);
 };
diff --git a/src/optimize/lazy/lazy_optimizer.js b/src/optimize/lazy/lazy_optimizer.js
index ca7b052e392f6..62c4e2cec0e06 100644
--- a/src/optimize/lazy/lazy_optimizer.js
+++ b/src/optimize/lazy/lazy_optimizer.js
@@ -41,7 +41,7 @@ module.exports = class LazyOptimizer extends BaseOptimizer {
         return;
       }
 
-      let err = this.failedStatsToError(stats);
+      const err = this.failedStatsToError(stats);
       this.logRunFailure(err);
       this.build.failure(err);
       this.watching.invalidate();
@@ -54,7 +54,7 @@ module.exports = class LazyOptimizer extends BaseOptimizer {
       }
     });
 
-    let buildPromise = this.build.get();
+    const buildPromise = this.build.get();
     if (this.prebuild) await buildPromise;
 
     this.initializing = false;
@@ -75,7 +75,7 @@ module.exports = class LazyOptimizer extends BaseOptimizer {
       method: 'GET',
       handler: async (request, reply) => {
         try {
-          let path = await this.getPath(request.params.asset);
+          const path = await this.getPath(request.params.asset);
           return reply.file(path);
         } catch (error) {
           console.log(error.stack);
diff --git a/src/optimize/lazy/optmzr_role.js b/src/optimize/lazy/optmzr_role.js
index 8c6a653fe0937..30f5f30ac73de 100644
--- a/src/optimize/lazy/optmzr_role.js
+++ b/src/optimize/lazy/optmzr_role.js
@@ -3,7 +3,7 @@ import LazyOptimizer from './lazy_optimizer';
 import { fromRoot } from '../../utils';
 
 export default async (kbnServer, kibanaHapiServer, config) => {
-  let server = new LazyServer(
+  const server = new LazyServer(
     config.get('optimize.lazyHost'),
     config.get('optimize.lazyPort'),
     new LazyOptimizer({
@@ -20,7 +20,7 @@ export default async (kbnServer, kibanaHapiServer, config) => {
 
   let ready = false;
 
-  let sendReady = () => {
+  const sendReady = () => {
     if (!process.connected) return;
     process.send(['WORKER_BROADCAST', { optimizeReady: ready }]);
   };
diff --git a/src/optimize/lazy/proxy_role.js b/src/optimize/lazy/proxy_role.js
index b9b0f26ed6a63..9ea0bceeec7c3 100644
--- a/src/optimize/lazy/proxy_role.js
+++ b/src/optimize/lazy/proxy_role.js
@@ -18,11 +18,11 @@ module.exports = (kbnServer, server, config) => {
   });
 
   return fromNode(cb => {
-    let timeout = setTimeout(() => {
+    const timeout = setTimeout(() => {
       cb(new Error('Server timedout waiting for the optimizer to become ready'));
     }, config.get('optimize.lazyProxyTimeout'));
 
-    let waiting = once(() => {
+    const waiting = once(() => {
       server.log(['info', 'optimize'], 'Waiting for optimizer completion');
     });
 
diff --git a/src/optimize/lazy/weird_control_flow.js b/src/optimize/lazy/weird_control_flow.js
index ae37cce688283..b6ca267cdc720 100644
--- a/src/optimize/lazy/weird_control_flow.js
+++ b/src/optimize/lazy/weird_control_flow.js
@@ -51,7 +51,7 @@ module.exports = class WeirdControlFlow {
   }
 
   _flush(args) {
-    for (let fn of this.handlers.splice(0)) {
+    for (const fn of this.handlers.splice(0)) {
       fn.apply(null, args);
     }
   }
diff --git a/src/server/config/__tests__/config.js b/src/server/config/__tests__/config.js
index 0dc60f98f6004..ab2cc65bed201 100644
--- a/src/server/config/__tests__/config.js
+++ b/src/server/config/__tests__/config.js
@@ -14,7 +14,7 @@ import Joi from 'joi';
  *
  */
 
-let data = {
+const data = {
   test: {
     hosts: ['host-01', 'host-02'],
     client: {
@@ -25,7 +25,7 @@ let data = {
   }
 };
 
-let schema = Joi.object({
+const schema = Joi.object({
   test: Joi.object({
     enable: Joi.boolean().default(true),
     hosts: Joi.array().items(Joi.string()),
@@ -44,39 +44,39 @@ describe('lib/config/config', function () {
     describe('constructor', function () {
 
       it('should not allow any config if the schema is not passed', function () {
-        let config = new Config();
-        let run = function () {
+        const config = new Config();
+        const run = function () {
           config.set('something.enable', true);
         };
         expect(run).to.throwException();
       });
 
       it('should allow keys in the schema', function () {
-        let config = new Config(schema);
-        let run = function () {
+        const config = new Config(schema);
+        const run = function () {
           config.set('test.client.host', 'http://localhost');
         };
         expect(run).to.not.throwException();
       });
 
       it('should not allow keys not in the schema', function () {
-        let config = new Config(schema);
-        let run = function () {
+        const config = new Config(schema);
+        const run = function () {
           config.set('paramNotDefinedInTheSchema', true);
         };
         expect(run).to.throwException();
       });
 
       it('should not allow child keys not in the schema', function () {
-        let config = new Config(schema);
-        let run = function () {
+        const config = new Config(schema);
+        const run = function () {
           config.set('test.client.paramNotDefinedInTheSchema', true);
         };
         expect(run).to.throwException();
       });
 
       it('should set defaults', function () {
-        let config = new Config(schema);
+        const config = new Config(schema);
         expect(config.get('test.enable')).to.be(true);
         expect(config.get('test.client.type')).to.be('datastore');
       });
@@ -92,7 +92,7 @@ describe('lib/config/config', function () {
 
       it('should reset the config object with new values', function () {
         config.set(data);
-        let newData = config.get();
+        const newData = config.get();
         newData.test.enable = false;
         config.resetTo(newData);
         expect(config.get()).to.eql(newData);
@@ -134,21 +134,21 @@ describe('lib/config/config', function () {
       });
 
       it('should use an object to set config values', function () {
-        let hosts = ['host-01', 'host-02'];
+        const hosts = ['host-01', 'host-02'];
         config.set({ test: { enable: false, hosts: hosts } });
         expect(config.get('test.enable')).to.be(false);
         expect(config.get('test.hosts')).to.eql(hosts);
       });
 
       it('should use a flatten object to set config values', function () {
-        let hosts = ['host-01', 'host-02'];
+        const hosts = ['host-01', 'host-02'];
         config.set({ 'test.enable': false, 'test.hosts': hosts });
         expect(config.get('test.enable')).to.be(false);
         expect(config.get('test.hosts')).to.eql(hosts);
       });
 
       it('should override values with just the values present', function () {
-        let newData = _.cloneDeep(data);
+        const newData = _.cloneDeep(data);
         config.set(data);
         newData.test.enable = false;
         config.set({ test: { enable: false } });
@@ -156,7 +156,7 @@ describe('lib/config/config', function () {
       });
 
       it('should thow an exception when setting a value with the wrong type', function (done) {
-        let run = function () {
+        const run = function () {
           config.set('test.enable', 'something');
         };
         expect(run).to.throwException(function (err) {
@@ -179,7 +179,7 @@ describe('lib/config/config', function () {
       });
 
       it('should return the whole config object when called without a key', function () {
-        let newData = _.cloneDeep(data);
+        const newData = _.cloneDeep(data);
         newData.test.enable = true;
         expect(config.get()).to.eql(newData);
       });
@@ -194,14 +194,14 @@ describe('lib/config/config', function () {
       });
 
       it('should throw exception for unknown config values', function () {
-        let run = function () {
+        const run = function () {
           config.get('test.does.not.exist');
         };
         expect(run).to.throwException(/Unknown config key: test.does.not.exist/);
       });
 
       it('should not throw exception for undefined known config values', function () {
-        let run = function getUndefValue() {
+        const run = function getUndefValue() {
           config.get('test.undefValue');
         };
         expect(run).to.not.throwException();
@@ -216,13 +216,13 @@ describe('lib/config/config', function () {
       });
 
       it('should allow you to extend the schema at the top level', function () {
-        let newSchema = Joi.object({ test: Joi.boolean().default(true) }).default();
+        const newSchema = Joi.object({ test: Joi.boolean().default(true) }).default();
         config.extendSchema('myTest', newSchema);
         expect(config.get('myTest.test')).to.be(true);
       });
 
       it('should allow you to extend the schema with a prefix', function () {
-        let newSchema = Joi.object({ test: Joi.boolean().default(true) }).default();
+        const newSchema = Joi.object({ test: Joi.boolean().default(true) }).default();
         config.extendSchema('prefix.myTest', newSchema);
         expect(config.get('prefix')).to.eql({ myTest: { test: true }});
         expect(config.get('prefix.myTest')).to.eql({ test: true });
@@ -230,8 +230,8 @@ describe('lib/config/config', function () {
       });
 
       it('should NOT allow you to extend the schema if somethign else is there', function () {
-        let newSchema = Joi.object({ test: Joi.boolean().default(true) }).default();
-        let run = function () {
+        const newSchema = Joi.object({ test: Joi.boolean().default(true) }).default();
+        const run = function () {
           config.extendSchema('test', newSchema);
         };
         expect(run).to.throwException();
@@ -241,7 +241,7 @@ describe('lib/config/config', function () {
 
     describe('#removeSchema(key)', function () {
       it('should completely remove the key', function () {
-        let config = new Config(Joi.object().keys({
+        const config = new Config(Joi.object().keys({
           a: Joi.number().default(1)
         }));
 
@@ -251,7 +251,7 @@ describe('lib/config/config', function () {
       });
 
       it('only removes existing keys', function () {
-        let config = new Config(Joi.object());
+        const config = new Config(Joi.object());
 
         expect(() => config.removeSchema('b')).to.throwException('Unknown schema');
       });
diff --git a/src/server/config/__tests__/explode_by.js b/src/server/config/__tests__/explode_by.js
index 3514413e575b6..52ab03e00d047 100644
--- a/src/server/config/__tests__/explode_by.js
+++ b/src/server/config/__tests__/explode_by.js
@@ -4,7 +4,7 @@ import expect from 'expect.js';
 describe('explode_by(dot, flatObject)', function () {
 
   it('should explode a flatten object with dots', function () {
-    let flatObject = {
+    const flatObject = {
       'test.enable': true,
       'test.hosts': ['host-01', 'host-02']
     };
@@ -17,7 +17,7 @@ describe('explode_by(dot, flatObject)', function () {
   });
 
   it('should explode a flatten object with slashes', function () {
-    let flatObject = {
+    const flatObject = {
       'test/enable': true,
       'test/hosts': ['host-01', 'host-02']
     };
diff --git a/src/server/config/__tests__/flatten_with.js b/src/server/config/__tests__/flatten_with.js
index 9dc40fc08097e..78864e490bc30 100644
--- a/src/server/config/__tests__/flatten_with.js
+++ b/src/server/config/__tests__/flatten_with.js
@@ -4,7 +4,7 @@ import expect from 'expect.js';
 describe('flatten_with(dot, nestedObj)', function () {
 
   it('should flatten object with dot', function () {
-    let nestedObj = {
+    const nestedObj = {
       test: {
         enable: true,
         hosts: ['host-01', 'host-02'],
diff --git a/src/server/config/__tests__/override.js b/src/server/config/__tests__/override.js
index 18b3117dcbe56..055e09d2f0f9f 100644
--- a/src/server/config/__tests__/override.js
+++ b/src/server/config/__tests__/override.js
@@ -4,7 +4,7 @@ import expect from 'expect.js';
 describe('override(target, source)', function () {
 
   it('should override the values form source to target', function () {
-    let target = {
+    const target = {
       test: {
         enable: true,
         host: ['host-01', 'host-02'],
@@ -13,7 +13,7 @@ describe('override(target, source)', function () {
         }
       }
     };
-    let source = { test: { client: { type: 'nosql' } } };
+    const source = { test: { client: { type: 'nosql' } } };
     expect(override(target, source)).to.eql({
       test: {
         enable: true,
diff --git a/src/server/config/complete.js b/src/server/config/complete.js
index be44448733782..aca586e81f9db 100644
--- a/src/server/config/complete.js
+++ b/src/server/config/complete.js
@@ -4,8 +4,8 @@ export default function (kbnServer, server, config) {
     return kbnServer.config;
   });
 
-  let tmpl = 'Settings for "<%= key %>" were not applied, check for spelling errors and ensure the plugin is loaded.';
-  for (let [key, val] of config.getPendingSets()) {
+  const tmpl = 'Settings for "<%= key %>" were not applied, check for spelling errors and ensure the plugin is loaded.';
+  for (const [key, val] of config.getPendingSets()) {
     server.log(['warning', 'config'], { key, val, tmpl });
   }
 };
diff --git a/src/server/config/config.js b/src/server/config/config.js
index 28c8ea4158138..db6b3520b776c 100644
--- a/src/server/config/config.js
+++ b/src/server/config/config.js
@@ -42,7 +42,7 @@ module.exports = class Config {
     _.set(this[schemaExts], key, extension);
     this[schema] = null;
 
-    let initialVals = _.get(this[pendingSets], key);
+    const initialVals = _.get(this[pendingSets], key);
     if (initialVals) {
       this.set(key, initialVals);
       unset(this[pendingSets], key);
@@ -86,11 +86,11 @@ module.exports = class Config {
     if (_.isObject(env)) env = env.name;
     if (!env) env = process.env.NODE_ENV || 'production';
 
-    let dev = env === 'development';
-    let prod = env === 'production';
+    const dev = env === 'development';
+    const prod = env === 'production';
 
     // pass the environment as context so that it can be refed in config
-    let context = {
+    const context = {
       env: env,
       prod: prod,
       dev: dev,
@@ -107,7 +107,7 @@ module.exports = class Config {
       );
     }
 
-    let results = Joi.validate(newVals, this.getSchema(), { context });
+    const results = Joi.validate(newVals, this.getSchema(), { context });
 
     if (results.error) {
       throw results.error;
@@ -121,7 +121,7 @@ module.exports = class Config {
       return clone(this[vals]);
     }
 
-    let value = _.get(this[vals], key);
+    const value = _.get(this[vals], key);
     if (value === undefined) {
       if (!this.has(key)) {
         throw new Error('Unknown config key: ' + key);
@@ -138,7 +138,7 @@ module.exports = class Config {
       // Only go deep on inner objects with children
       if (_.size(schema._inner.children)) {
         for (let i = 0; i < schema._inner.children.length; i++) {
-          let child = schema._inner.children[i];
+          const child = schema._inner.children[i];
           // If the child is an object recurse through it's children and return
           // true if there's a match
           if (child.schema._type === 'object') {
diff --git a/src/server/config/explode_by.js b/src/server/config/explode_by.js
index 50e2b2e82615f..a2e632ddf2a68 100644
--- a/src/server/config/explode_by.js
+++ b/src/server/config/explode_by.js
@@ -1,10 +1,10 @@
 import _ from 'lodash';
 module.exports = function (dot, flatObject) {
-  let fullObject = {};
+  const fullObject = {};
   _.each(flatObject, function (value, key) {
-    let keys = key.split(dot);
+    const keys = key.split(dot);
     (function walk(memo, keys, value) {
-      let _key = keys.shift();
+      const _key = keys.shift();
       if (keys.length === 0) {
         memo[_key] = value;
       } else {
diff --git a/src/server/config/flatten_with.js b/src/server/config/flatten_with.js
index 1401e12f0fb85..ede084f56a3fc 100644
--- a/src/server/config/flatten_with.js
+++ b/src/server/config/flatten_with.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 module.exports = function (dot, nestedObj, flattenArrays) {
-  let stack = []; // track key stack
-  let flatObj = {};
+  const stack = []; // track key stack
+  const flatObj = {};
   (function flattenObj(obj) {
     _.keys(obj).forEach(function (key) {
       stack.push(key);
diff --git a/src/server/config/override.js b/src/server/config/override.js
index ef850a32754ae..3354fd5956fe7 100644
--- a/src/server/config/override.js
+++ b/src/server/config/override.js
@@ -3,8 +3,8 @@ import flattenWith from './flatten_with';
 import explodeBy from './explode_by';
 
 module.exports = function (target, source) {
-  let _target = flattenWith('.', target);
-  let _source = flattenWith('.', source);
+  const _target = flattenWith('.', target);
+  const _source = flattenWith('.', source);
   return explodeBy('.', _.defaults(_source, _target));
 };
 
diff --git a/src/server/http/index.js b/src/server/http/index.js
index b6440bec66044..8ddb933f5cd5c 100644
--- a/src/server/http/index.js
+++ b/src/server/http/index.js
@@ -65,7 +65,7 @@ module.exports = async function (kbnServer, server, config) {
 
   // attach the app name to the server, so we can be sure we are actually talking to kibana
   server.ext('onPreResponse', function (req, reply) {
-    let response = req.response;
+    const response = req.response;
 
     if (response.isBoom) {
       response.output.headers['kbn-name'] = kbnServer.name;
@@ -93,7 +93,7 @@ module.exports = async function (kbnServer, server, config) {
     method: 'GET',
     path: '/{p*}',
     handler: function (req, reply) {
-      let path = req.path;
+      const path = req.path;
       if (path === '/' || path.charAt(path.length - 1) !== '/') {
         return reply(Boom.notFound());
       }
diff --git a/src/server/kbn_server.js b/src/server/kbn_server.js
index 8ad9d9c0709d8..3a7af43975953 100644
--- a/src/server/kbn_server.js
+++ b/src/server/kbn_server.js
@@ -6,7 +6,7 @@ import { fromRoot, pkg } from '../utils';
 import Config from './config/config';
 import loggingConfiguration from './logging/configuration';
 
-let rootDir = fromRoot('.');
+const rootDir = fromRoot('.');
 
 module.exports = class KbnServer {
   constructor(settings) {
@@ -66,7 +66,7 @@ module.exports = class KbnServer {
    * @return {Promise} - promise that is resolved when the final mixin completes.
    */
   async mixin(...fns) {
-    for (let fn of compact(flatten(fns))) {
+    for (const fn of compact(flatten(fns))) {
       await fn.call(this, this, this.server, this.config);
     }
   }
@@ -78,7 +78,7 @@ module.exports = class KbnServer {
    * @return undefined
    */
   async listen() {
-    let { server, config } = this;
+    const { server, config } = this;
 
     await this.ready();
     await fromNode(cb => server.start(cb));
diff --git a/src/server/logging/__tests__/apply_filters_to_keys.js b/src/server/logging/__tests__/apply_filters_to_keys.js
index 0175b90ff221b..02c3efab19b43 100644
--- a/src/server/logging/__tests__/apply_filters_to_keys.js
+++ b/src/server/logging/__tests__/apply_filters_to_keys.js
@@ -3,7 +3,7 @@ import expect from 'expect.js';
 
 describe('applyFiltersToKeys(obj, actionsByKey)', function () {
   it('applies for each key+prop in actionsByKey', function () {
-    let data = applyFiltersToKeys({
+    const data = applyFiltersToKeys({
       a: {
         b: {
           c: 1
diff --git a/src/server/logging/apply_filters_to_keys.js b/src/server/logging/apply_filters_to_keys.js
index bc85f2fd1f555..19dc6e5d154d8 100644
--- a/src/server/logging/apply_filters_to_keys.js
+++ b/src/server/logging/apply_filters_to_keys.js
@@ -7,7 +7,7 @@ function replacer(match, group) {
 }
 
 function apply(obj, key, action) {
-  for (let k in obj)  {
+  for (const k in obj)  {
     if (obj.hasOwnProperty(k)) {
       let val = obj[k];
       if (k === key) {
@@ -21,9 +21,9 @@ function apply(obj, key, action) {
           obj[k] = ('' + val).replace(/./g, 'X');
         }
         else if (/\/.+\//.test(action)) {
-          let matches = action.match(/\/(.+)\//);
+          const matches = action.match(/\/(.+)\//);
           if (matches) {
-            let regex = new RegExp(matches[1]);
+            const regex = new RegExp(matches[1]);
             obj[k] = ('' + val).replace(regex, replacer);
           }
         }
diff --git a/src/server/logging/configuration.js b/src/server/logging/configuration.js
index 2a894a0d97e44..be66a2e738c8b 100644
--- a/src/server/logging/configuration.js
+++ b/src/server/logging/configuration.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import logReporter from './log_reporter';
 
 export default function loggingConfiguration(config) {
-  let events = config.get('logging.events');
+  const events = config.get('logging.events');
 
   if (config.get('logging.silent')) {
     _.defaults(events, {});
diff --git a/src/server/logging/log_format.js b/src/server/logging/log_format.js
index 7d11c59abd265..7a077ecdd5c27 100644
--- a/src/server/logging/log_format.js
+++ b/src/server/logging/log_format.js
@@ -18,7 +18,7 @@ function serializeError(err) {
   };
 }
 
-let levelColor = function (code) {
+const levelColor = function (code) {
   if (code < 299) return ansicolors.green(code);
   if (code < 399) return ansicolors.yellow(code);
   if (code < 499) return ansicolors.magenta(code);
@@ -41,13 +41,13 @@ module.exports = class TransformObjStream extends Stream.Transform {
   }
 
   _transform(event, enc, next) {
-    let data = this.filter(this.readEvent(event));
+    const data = this.filter(this.readEvent(event));
     this.push(this.format(data) + '\n');
     next();
   }
 
   readEvent(event) {
-    let data = {
+    const data = {
       type: event.event,
       '@timestamp': moment.utc(event.timestamp).format(),
       tags: [].concat(event.tags || []),
@@ -82,7 +82,7 @@ module.exports = class TransformObjStream extends Stream.Transform {
         contentLength: contentLength
       };
 
-      let query = querystring.stringify(event.query);
+      const query = querystring.stringify(event.query);
       if (query) data.req.url += '?' + query;
 
 
diff --git a/src/server/logging/log_format_json.js b/src/server/logging/log_format_json.js
index 7df528ab968bb..440982bbd3ea7 100644
--- a/src/server/logging/log_format_json.js
+++ b/src/server/logging/log_format_json.js
@@ -1,7 +1,7 @@
 import LogFormat from './log_format';
 import stringify from 'json-stringify-safe';
 
-let stripColors = function (string) {
+const stripColors = function (string) {
   return string.replace(/\u001b[^m]+m/g, '');
 };
 
diff --git a/src/server/logging/log_format_string.js b/src/server/logging/log_format_string.js
index 189738a1b4c52..b333510f53ace 100644
--- a/src/server/logging/log_format_string.js
+++ b/src/server/logging/log_format_string.js
@@ -4,7 +4,7 @@ import moment from 'moment';
 
 import LogFormat from './log_format';
 
-let statuses = [
+const statuses = [
   'err',
   'info',
   'error',
@@ -14,7 +14,7 @@ let statuses = [
   'debug'
 ];
 
-let typeColors = {
+const typeColors = {
   log: 'blue',
   req: 'green',
   res: 'green',
@@ -34,22 +34,22 @@ let typeColors = {
   listening: 'magenta'
 };
 
-let color = _.memoize(function (name) {
+const color = _.memoize(function (name) {
   return ansicolors[typeColors[name]] || _.identity;
 });
 
-let type = _.memoize(function (t) {
+const type = _.memoize(function (t) {
   return color(t)(_.pad(t, 7).slice(0, 7));
 });
 
-let workerType = process.env.kbnWorkerType ? `${type(process.env.kbnWorkerType)} ` : '';
+const workerType = process.env.kbnWorkerType ? `${type(process.env.kbnWorkerType)} ` : '';
 
 module.exports = class KbnLoggerJsonFormat extends LogFormat {
   format(data) {
-    let time = color('time')(moment(data.timestamp).format('HH:mm:ss.SSS'));
-    let msg = data.error ? color('error')(data.error.stack) : color('message')(data.message);
+    const time = color('time')(moment(data.timestamp).format('HH:mm:ss.SSS'));
+    const msg = data.error ? color('error')(data.error.stack) : color('message')(data.message);
 
-    let tags = _(data.tags)
+    const tags = _(data.tags)
     .sortBy(function (tag) {
       if (color(tag) === _.identity) return `2${tag}`;
       if (_.includes(statuses, tag)) return `0${tag}`;
diff --git a/src/server/pid/index.js b/src/server/pid/index.js
index 7d7c1dbdea0fb..a2dc452480e09 100644
--- a/src/server/pid/index.js
+++ b/src/server/pid/index.js
@@ -2,19 +2,19 @@ import _ from 'lodash';
 import Boom from 'boom';
 import Promise from 'bluebird';
 import { unlinkSync as unlink } from 'fs';
-let writeFile = Promise.promisify(require('fs').writeFile);
+const writeFile = Promise.promisify(require('fs').writeFile);
 
 module.exports = Promise.method(function (kbnServer, server, config) {
-  let path = config.get('pid.file');
+  const path = config.get('pid.file');
   if (!path) return;
 
-  let pid = String(process.pid);
+  const pid = String(process.pid);
 
   return writeFile(path, pid, { flag: 'wx' })
   .catch(function (err) {
     if (err.code !== 'EEXIST') throw err;
 
-    let log = {
+    const log = {
       tmpl: 'pid file already exists at <%= path %>',
       path: path,
       pid: pid
@@ -36,7 +36,7 @@ module.exports = Promise.method(function (kbnServer, server, config) {
       pid: pid
     });
 
-    let clean = _.once(function (code) {
+    const clean = _.once(function (code) {
       unlink(path);
     });
 
diff --git a/src/server/plugins/initialize.js b/src/server/plugins/initialize.js
index 402b750fbcc03..262c2a9d0b6d2 100644
--- a/src/server/plugins/initialize.js
+++ b/src/server/plugins/initialize.js
@@ -7,7 +7,7 @@ module.exports = async function (kbnServer, server, config) {
     return [];
   }
 
-  let { plugins } = kbnServer;
+  const { plugins } = kbnServer;
 
   // extend plugin apis with additional context
   plugins.getPluginApis().forEach(api => {
diff --git a/src/server/plugins/plugin.js b/src/server/plugins/plugin.js
index bd44048bd1ad3..3c874470100a5 100644
--- a/src/server/plugins/plugin.js
+++ b/src/server/plugins/plugin.js
@@ -90,8 +90,8 @@ module.exports = class Plugin {
   }
 
   async readConfig() {
-    let schema = await this.getConfigSchema(Joi);
-    let { config } = this.kbnServer;
+    const schema = await this.getConfigSchema(Joi);
+    const { config } = this.kbnServer;
     config.extendSchema(this.configPrefix, schema || defaultConfigSchema);
 
     if (config.get([...toPath(this.configPrefix), 'enabled'])) {
@@ -107,8 +107,8 @@ module.exports = class Plugin {
   }
 
   async init() {
-    let { id, version, kbnServer, configPrefix } = this;
-    let { config } = kbnServer;
+    const { id, version, kbnServer, configPrefix } = this;
+    const { config } = kbnServer;
 
     // setup the hapi register function and get on with it
     const asyncRegister = async (server, options) => {
diff --git a/src/server/plugins/plugin_collection.js b/src/server/plugins/plugin_collection.js
index 6019fd3baf60b..a7ed9689ae472 100644
--- a/src/server/plugins/plugin_collection.js
+++ b/src/server/plugins/plugin_collection.js
@@ -4,8 +4,8 @@ import { inspect } from 'util';
 import { get, indexBy } from 'lodash';
 import Collection from '../../utils/collection';
 
-let byIdCache = Symbol('byIdCache');
-let pluginApis = Symbol('pluginApis');
+const byIdCache = Symbol('byIdCache');
+const pluginApis = Symbol('pluginApis');
 
 module.exports = class Plugins extends Collection {
 
@@ -16,24 +16,24 @@ module.exports = class Plugins extends Collection {
   }
 
   async new(path) {
-    let api = new PluginApi(this.kbnServer, path);
+    const api = new PluginApi(this.kbnServer, path);
     this[pluginApis].add(api);
 
-    let output = [].concat(require(path)(api) || []);
-    let config = this.kbnServer.config;
+    const output = [].concat(require(path)(api) || []);
+    const config = this.kbnServer.config;
 
     if (!output.length) return;
 
     // clear the byIdCache
     this[byIdCache] = null;
 
-    for (let product of output) {
+    for (const product of output) {
 
       if (product instanceof api.Plugin) {
-        let plugin = product;
+        const plugin = product;
         this.add(plugin);
 
-        let enabled = await plugin.readConfig();
+        const enabled = await plugin.readConfig();
         if (!enabled) this.delete(plugin);
         continue;
       }
diff --git a/src/server/plugins/plugin_init.js b/src/server/plugins/plugin_init.js
index 8f5e9e3184478..7823b4669f42e 100644
--- a/src/server/plugins/plugin_init.js
+++ b/src/server/plugins/plugin_init.js
@@ -1,10 +1,10 @@
 import { includes } from 'lodash';
 
 export default async (plugins) => {
-  let path = [];
+  const path = [];
 
   const initialize = async function (id, fn) {
-    let plugin = plugins.byId[id];
+    const plugin = plugins.byId[id];
 
     if (includes(path, id)) {
       throw new Error(`circular dependencies found: "${path.concat(id).join(' -> ')}"`);
@@ -12,7 +12,7 @@ export default async (plugins) => {
 
     path.push(id);
 
-    for (let reqId of plugin.requiredIds) {
+    for (const reqId of plugin.requiredIds) {
       if (!plugins.byId[reqId]) {
         throw new Error(`Unmet requirement "${reqId}" for plugin "${id}"`);
       }
@@ -25,11 +25,11 @@ export default async (plugins) => {
   };
 
   const collection = plugins.toArray();
-  for (let {id} of collection) {
+  for (const {id} of collection) {
     await initialize(id, 'preInit');
   }
 
-  for (let {id} of collection) {
+  for (const {id} of collection) {
     await initialize(id, 'init');
   }
 };
diff --git a/src/server/plugins/scan.js b/src/server/plugins/scan.js
index baa5147e44530..4ac6b3e5563ff 100644
--- a/src/server/plugins/scan.js
+++ b/src/server/plugins/scan.js
@@ -6,13 +6,13 @@ import { each } from 'bluebird';
 import PluginCollection from './plugin_collection';
 module.exports = async (kbnServer, server, config) => {
 
-  let plugins = kbnServer.plugins = new PluginCollection(kbnServer);
+  const plugins = kbnServer.plugins = new PluginCollection(kbnServer);
 
-  let scanDirs = [].concat(config.get('plugins.scanDirs') || []);
-  let pluginPaths = [].concat(config.get('plugins.paths') || []);
+  const scanDirs = [].concat(config.get('plugins.scanDirs') || []);
+  const pluginPaths = [].concat(config.get('plugins.paths') || []);
 
-  let debug = _.bindKey(server, 'log', ['plugins', 'debug']);
-  let warning = _.bindKey(server, 'log', ['plugins', 'warning']);
+  const debug = _.bindKey(server, 'log', ['plugins', 'debug']);
+  const warning = _.bindKey(server, 'log', ['plugins', 'warning']);
 
   // scan all scanDirs to find pluginPaths
   await each(scanDirs, async dir => {
@@ -36,15 +36,15 @@ module.exports = async (kbnServer, server, config) => {
     await each(filenames, async name => {
       if (name[0] === '.') return;
 
-      let path = resolve(dir, name);
-      let stats = await fromNode(cb => stat(path, cb));
+      const path = resolve(dir, name);
+      const stats = await fromNode(cb => stat(path, cb));
       if (stats.isDirectory()) {
         pluginPaths.push(path);
       }
     });
   });
 
-  for (let path of pluginPaths) {
+  for (const path of pluginPaths) {
     let modulePath;
     try {
       modulePath = require.resolve(path);
diff --git a/src/server/status/__tests__/server_status.js b/src/server/status/__tests__/server_status.js
index 3d08250fbf81f..a1379d9373eaf 100644
--- a/src/server/status/__tests__/server_status.js
+++ b/src/server/status/__tests__/server_status.js
@@ -26,7 +26,7 @@ describe('ServerStatus class', function () {
 
   describe('#createForPlugin(plugin)', function () {
     it('should create a new status by plugin', function () {
-      let status = serverStatus.createForPlugin(plugin);
+      const status = serverStatus.createForPlugin(plugin);
       expect(status).to.be.a(Status);
     });
   });
@@ -45,7 +45,7 @@ describe('ServerStatus class', function () {
 
   describe('#getForPluginId(plugin)', function () {
     it('exposes plugin status for the plugin', function () {
-      let status = serverStatus.createForPlugin(plugin);
+      const status = serverStatus.createForPlugin(plugin);
       expect(serverStatus.getForPluginId(plugin.id)).to.be(status);
     });
 
@@ -57,7 +57,7 @@ describe('ServerStatus class', function () {
 
   describe('#getState(id)', function () {
     it('should expose the state of a status by id', function () {
-      let status = serverStatus.create('someid');
+      const status = serverStatus.create('someid');
       status.green();
       expect(serverStatus.getState('someid')).to.be('green');
     });
@@ -65,7 +65,7 @@ describe('ServerStatus class', function () {
 
   describe('#getStateForPluginId(plugin)', function () {
     it('should expose the state of a plugin by id', function () {
-      let status = serverStatus.createForPlugin(plugin);
+      const status = serverStatus.createForPlugin(plugin);
       status.green();
       expect(serverStatus.getStateForPluginId(plugin.id)).to.be('green');
     });
@@ -73,11 +73,11 @@ describe('ServerStatus class', function () {
 
   describe('#overall()', function () {
     it('considers each status to produce a summary', function () {
-      let status = serverStatus.createForPlugin(plugin);
+      const status = serverStatus.createForPlugin(plugin);
 
       expect(serverStatus.overall().state).to.be('uninitialized');
 
-      let match = function (overall, state) {
+      const match = function (overall, state) {
         expect(overall).to.have.property('state', state.id);
         expect(overall).to.have.property('title', state.title);
         expect(overall).to.have.property('icon', state.icon);
@@ -102,15 +102,15 @@ describe('ServerStatus class', function () {
       const pluginOne = {id: 'one', version: '1.0.0'};
       const pluginTwo = {id: 'two', version: '2.0.0'};
 
-      let service = serverStatus.create('some service');
-      let p1 = serverStatus.createForPlugin(pluginOne);
-      let p2 = serverStatus.createForPlugin(pluginTwo);
+      const service = serverStatus.create('some service');
+      const p1 = serverStatus.createForPlugin(pluginOne);
+      const p2 = serverStatus.createForPlugin(pluginTwo);
 
       service.green();
       p1.yellow();
       p2.red();
 
-      let json = JSON.parse(JSON.stringify(serverStatus));
+      const json = JSON.parse(JSON.stringify(serverStatus));
       expect(json).to.have.property('overall');
       expect(json.overall.state).to.eql(serverStatus.overall().state);
       expect(json.statuses).to.have.length(3);
diff --git a/src/server/status/__tests__/status.js b/src/server/status/__tests__/status.js
index 2dfe037791027..810a84cabe30e 100644
--- a/src/server/status/__tests__/status.js
+++ b/src/server/status/__tests__/status.js
@@ -19,7 +19,7 @@ describe('Status class', function () {
   });
 
   it('emits change when the status is set', function (done) {
-    let status = serverStatus.createForPlugin(plugin);
+    const status = serverStatus.createForPlugin(plugin);
 
     status.once('change', function (prevState, prevMsg, newState, newMsg) {
       expect(newState).to.be('green');
@@ -42,8 +42,8 @@ describe('Status class', function () {
   });
 
   it('should only trigger the change listener when something changes', function () {
-    let status = serverStatus.createForPlugin(plugin);
-    let stub = sinon.stub();
+    const status = serverStatus.createForPlugin(plugin);
+    const stub = sinon.stub();
     status.on('change', stub);
     status.green('Ready');
     status.green('Ready');
@@ -52,18 +52,18 @@ describe('Status class', function () {
   });
 
   it('should create a JSON representation of the status', function () {
-    let status = serverStatus.createForPlugin(plugin);
+    const status = serverStatus.createForPlugin(plugin);
     status.green('Ready');
 
-    let json = status.toJSON();
+    const json = status.toJSON();
     expect(json.id).to.eql(status.id);
     expect(json.state).to.eql('green');
     expect(json.message).to.eql('Ready');
   });
 
   it('should call on handler if status is already matched', function (done) {
-    let status = serverStatus.createForPlugin(plugin);
-    let msg = 'Test Ready';
+    const status = serverStatus.createForPlugin(plugin);
+    const msg = 'Test Ready';
     status.green(msg);
 
     status.on('green', function (prev, prevMsg) {
@@ -76,8 +76,8 @@ describe('Status class', function () {
   });
 
   it('should call once handler if status is already matched', function (done) {
-    let status = serverStatus.createForPlugin(plugin);
-    let msg = 'Test Ready';
+    const status = serverStatus.createForPlugin(plugin);
+    const msg = 'Test Ready';
     status.green(msg);
 
     status.once('green', function (prev, prevMsg) {
@@ -91,16 +91,16 @@ describe('Status class', function () {
 
   function testState(color) {
     it(`should change the state to ${color} when #${color}() is called`, function () {
-      let status = serverStatus.createForPlugin(plugin);
-      let message = 'testing ' + color;
+      const status = serverStatus.createForPlugin(plugin);
+      const message = 'testing ' + color;
       status[color](message);
       expect(status).to.have.property('state', color);
       expect(status).to.have.property('message', message);
     });
 
     it(`should trigger the "change" listner when #${color}() is called`, function (done) {
-      let status = serverStatus.createForPlugin(plugin);
-      let message = 'testing ' + color;
+      const status = serverStatus.createForPlugin(plugin);
+      const message = 'testing ' + color;
       status.on('change', function (prev, prevMsg) {
         expect(status.state).to.be(color);
         expect(status.message).to.be(message);
@@ -113,8 +113,8 @@ describe('Status class', function () {
     });
 
     it(`should trigger the "${color}" listner when #${color}() is called`, function (done) {
-      let status = serverStatus.createForPlugin(plugin);
-      let message = 'testing ' + color;
+      const status = serverStatus.createForPlugin(plugin);
+      const message = 'testing ' + color;
       status.on(color, function (prev, prevMsg) {
         expect(status.state).to.be(color);
         expect(status.message).to.be(message);
diff --git a/src/server/status/metrics.js b/src/server/status/metrics.js
index 28b99011bc988..d00a8eb540d04 100644
--- a/src/server/status/metrics.js
+++ b/src/server/status/metrics.js
@@ -6,13 +6,13 @@ module.exports = function (kbnServer, server, config) {
   kbnServer.metrics = new Samples(12);
 
   server.plugins['even-better'].monitor.on('ops', function (event) {
-    let now = Date.now();
-    let secSinceLast = (now - lastReport) / 1000;
+    const now = Date.now();
+    const secSinceLast = (now - lastReport) / 1000;
     lastReport = now;
 
-    let port = config.get('server.port');
-    let requests = _.get(event, ['requests', port, 'total'], 0);
-    let requestsPerSecond = requests / secSinceLast;
+    const port = config.get('server.port');
+    const requests = _.get(event, ['requests', port, 'total'], 0);
+    const requestsPerSecond = requests / secSinceLast;
 
     kbnServer.metrics.add({
       heapTotal: _.get(event, 'psmem.heapTotal'),
diff --git a/src/server/status/samples.js b/src/server/status/samples.js
index fd2bc4aa27c84..20164c07b7834 100644
--- a/src/server/status/samples.js
+++ b/src/server/status/samples.js
@@ -7,8 +7,8 @@ function Samples(max) {
 }
 
 Samples.prototype.add = function (sample) {
-  let vals = this.vals;
-  let length = this.length = Math.min(this.length + 1, this.max);
+  const vals = this.vals;
+  const length = this.length = Math.min(this.length + 1, this.max);
 
   _.forOwn(sample, function (val, name) {
     if (val == null) val = null;
diff --git a/src/server/status/server_status.js b/src/server/status/server_status.js
index 88c44354f2e71..ac9b4fa855e2e 100644
--- a/src/server/status/server_status.js
+++ b/src/server/status/server_status.js
@@ -24,7 +24,7 @@ module.exports = class ServerStatus {
   }
 
   each(fn) {
-    let self = this;
+    const self = this;
     _.forOwn(self._created, function (status, i, list) {
       if (status.state !== 'disabled') {
         fn.call(self, status, i, list);
@@ -55,15 +55,15 @@ module.exports = class ServerStatus {
   }
 
   overall() {
-    let state = _(this._created)
+    const state = _(this._created)
     .map(function (status) {
       return states.get(status.state);
     })
     .sortBy('severity')
     .pop();
 
-    let statuses = _.where(this._created, { state: state.id });
-    let since = _.get(_.sortBy(statuses, 'since'), [0, 'since']);
+    const statuses = _.where(this._created, { state: state.id });
+    const since = _.get(_.sortBy(statuses, 'since'), [0, 'since']);
 
     return {
       state: state.id,
@@ -83,7 +83,7 @@ module.exports = class ServerStatus {
   }
 
   toString() {
-    let overall = this.overall();
+    const overall = this.overall();
     return `${overall.title} – ${overall.nickname}`;
   }
 
diff --git a/src/server/status/status.js b/src/server/status/status.js
index 573eb041a2a6b..f8848f680b50c 100644
--- a/src/server/status/status.js
+++ b/src/server/status/status.js
@@ -65,8 +65,8 @@ states.all.forEach(function (state) {
   Status.prototype[state.id] = function (message) {
     if (this.state === 'disabled') return;
 
-    let previous = this.state;
-    let previousMsg = this.message;
+    const previous = this.state;
+    const previousMsg = this.message;
 
     this.error = null;
     this.message = message || state.title;
diff --git a/src/test_utils/simulate_keys.js b/src/test_utils/simulate_keys.js
index 8282d8e5cc9e3..b9c55f92e35a7 100644
--- a/src/test_utils/simulate_keys.js
+++ b/src/test_utils/simulate_keys.js
@@ -2,8 +2,8 @@ import $ from 'jquery';
 import _ from 'lodash';
 import Promise from 'bluebird';
 import keyMap from 'ui/utils/key_map';
-let reverseKeyMap = _.mapValues(_.invert(keyMap), _.ary(_.parseInt, 1));
-let KeyboardEvent = window.KeyboardEvent;
+const reverseKeyMap = _.mapValues(_.invert(keyMap), _.ary(_.parseInt, 1));
+const KeyboardEvent = window.KeyboardEvent;
 
 /**
  * Simulate keyboard events in an element. This allows testing the way that
@@ -35,7 +35,7 @@ let KeyboardEvent = window.KeyboardEvent;
  * @async
  */
 export default function ($el, sequence) {
-  let modifierState = {
+  const modifierState = {
     ctrlKey: false,
     shiftKey: false,
     altKey: false,
@@ -45,7 +45,7 @@ export default function ($el, sequence) {
   return doList(_.clone(sequence));
 
   function setModifier(key, state) {
-    let name = key + 'Key';
+    const name = key + 'Key';
     if (modifierState.hasOwnProperty(name)) {
       modifierState[name] = !!state;
     }
@@ -91,14 +91,14 @@ export default function ($el, sequence) {
   }
 
   function fire(type, key, repeat) {
-    let keyCode = reverseKeyMap[key];
+    const keyCode = reverseKeyMap[key];
     if (!keyCode) throw new TypeError('invalid key "' + key + '"');
 
     if (type === 'keydown') setModifier(key, true);
     if (type === 'keyup') setModifier(key, false);
 
-    let $target = _.isFunction($el) ? $el() : $el;
-    let $event = new $.Event(type, _.defaults({ keyCode: keyCode }, modifierState));
+    const $target = _.isFunction($el) ? $el() : $el;
+    const $event = new $.Event(type, _.defaults({ keyCode: keyCode }, modifierState));
     $target.trigger($event);
   }
 };
diff --git a/src/test_utils/stub_index_pattern.js b/src/test_utils/stub_index_pattern.js
index 84f33eb229438..81f1481dd717b 100644
--- a/src/test_utils/stub_index_pattern.js
+++ b/src/test_utils/stub_index_pattern.js
@@ -9,10 +9,10 @@ import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import IndexPatternsFlattenHitProvider from 'ui/index_patterns/_flatten_hit';
 import IndexPatternsFieldProvider from 'ui/index_patterns/_field';
 export default function (Private) {
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
-  let flattenHit = Private(IndexPatternsFlattenHitProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
+  const flattenHit = Private(IndexPatternsFlattenHitProvider);
 
-  let Field = Private(IndexPatternsFieldProvider);
+  const Field = Private(IndexPatternsFieldProvider);
 
   function StubIndexPattern(pattern, timeField, fields) {
     this.id = pattern;
diff --git a/src/ui/__tests__/ui_exports.js b/src/ui/__tests__/ui_exports.js
index e5f6996af5fee..dcc87ccacb0a5 100644
--- a/src/ui/__tests__/ui_exports.js
+++ b/src/ui/__tests__/ui_exports.js
@@ -7,7 +7,7 @@ import * as kbnTestServer from '../../../test/utils/kbn_server';
 describe('UiExports', function () {
   describe('#find()', function () {
     it('finds exports based on the passed export names', function () {
-      let uiExports = new UiExports({});
+      const uiExports = new UiExports({});
       uiExports.aliases.foo = ['a', 'b', 'c'];
       uiExports.aliases.bar = ['d', 'e', 'f'];
 
@@ -17,7 +17,7 @@ describe('UiExports', function () {
     });
 
     it('allows query types that match nothing', function () {
-      let uiExports = new UiExports({});
+      const uiExports = new UiExports({});
       uiExports.aliases.foo = ['a', 'b', 'c'];
 
       expect(uiExports.find(['foo'])).to.eql(['a', 'b', 'c']);
diff --git a/src/ui/index.js b/src/ui/index.js
index ada8fa2a0f069..bf4946fdb19ba 100644
--- a/src/ui/index.js
+++ b/src/ui/index.js
@@ -25,17 +25,17 @@ export default async (kbnServer, server, config) => {
   bundlerEnv.addContext('buildNum', config.get('pkg.buildNum'));
   uiExports.addConsumer(bundlerEnv);
 
-  for (let plugin of kbnServer.plugins) {
+  for (const plugin of kbnServer.plugins) {
     uiExports.consumePlugin(plugin);
   }
 
   const bundles = kbnServer.bundles = new UiBundleCollection(bundlerEnv, config.get('optimize.bundleFilter'));
 
-  for (let app of uiExports.getAllApps()) {
+  for (const app of uiExports.getAllApps()) {
     bundles.addApp(app);
   }
 
-  for (let gen of uiExports.getBundleProviders()) {
+  for (const gen of uiExports.getBundleProviders()) {
     const bundle = await gen(UiBundle, bundlerEnv, uiExports.getAllApps(), kbnServer.plugins);
     if (bundle) bundles.add(bundle);
   }
diff --git a/src/ui/public/agg_response/geo_json/__tests__/geo_json.js b/src/ui/public/agg_response/geo_json/__tests__/geo_json.js
index 94bb16a66cb98..0d7b18f02abea 100644
--- a/src/ui/public/agg_response/geo_json/__tests__/geo_json.js
+++ b/src/ui/public/agg_response/geo_json/__tests__/geo_json.js
@@ -17,8 +17,8 @@ describe('GeoJson Agg Response Converter', function () {
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function (Private) {
-    let Vis = Private(VisProvider);
-    let indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
+    const Vis = Private(VisProvider);
+    const indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
 
     esResponse = Private(FixturesAggRespGeohashGridProvider);
     tabify = Private(AggResponseTabifyTabifyProvider);
@@ -60,8 +60,8 @@ describe('GeoJson Agg Response Converter', function () {
 
     describe('with table ' + JSON.stringify(tableOpts), function () {
       it('outputs a chart', function () {
-        let table = makeTable();
-        let chart = makeSingleChart(table);
+        const table = makeTable();
+        const chart = makeSingleChart(table);
         expect(chart).to.only.have.keys(
           'title',
           'tooltipFormatter',
@@ -78,9 +78,9 @@ describe('GeoJson Agg Response Converter', function () {
       });
 
       it('outputs geohash points as features in a feature collection', function () {
-        let table = makeTable();
-        let chart = makeSingleChart(table);
-        let geoJson = chart.geoJson;
+        const table = makeTable();
+        const chart = makeSingleChart(table);
+        const geoJson = chart.geoJson;
 
         expect(geoJson.type).to.be('FeatureCollection');
         expect(geoJson.features).to.be.an('array');
@@ -88,8 +88,8 @@ describe('GeoJson Agg Response Converter', function () {
       });
 
       it('exports a bunch of properties about the geo hash grid', function () {
-        let geoJson = makeGeoJson();
-        let props = geoJson.properties;
+        const geoJson = makeGeoJson();
+        const props = geoJson.properties;
 
         // props
         expect(props).to.be.an('object');
@@ -122,7 +122,7 @@ describe('GeoJson Agg Response Converter', function () {
 
           it('should be geoJson format', function () {
             table.rows.forEach(function (row, i) {
-              let feature = chart.geoJson.features[i];
+              const feature = chart.geoJson.features[i];
               expect(feature).to.have.property('geometry');
               expect(feature.geometry).to.be.an('object');
               expect(feature).to.have.property('properties');
@@ -132,7 +132,7 @@ describe('GeoJson Agg Response Converter', function () {
 
           it('should have valid geometry data', function () {
             table.rows.forEach(function (row, i) {
-              let geometry = chart.geoJson.features[i].geometry;
+              const geometry = chart.geoJson.features[i].geometry;
               expect(geometry.type).to.be('Point');
               expect(geometry).to.have.property('coordinates');
               expect(geometry.coordinates).to.be.an('array');
@@ -144,8 +144,8 @@ describe('GeoJson Agg Response Converter', function () {
 
           it('should have value properties data', function () {
             table.rows.forEach(function (row, i) {
-              let props = chart.geoJson.features[i].properties;
-              let keys = ['value', 'geohash', 'aggConfigResult', 'rectangle', 'center'];
+              const props = chart.geoJson.features[i].properties;
+              const keys = ['value', 'geohash', 'aggConfigResult', 'rectangle', 'center'];
               expect(props).to.be.an('object');
               expect(props).to.only.have.keys(keys);
               expect(props.geohash).to.be.a('string');
@@ -155,15 +155,15 @@ describe('GeoJson Agg Response Converter', function () {
 
           it('should use latLng in properties and lngLat in geometry', function () {
             table.rows.forEach(function (row, i) {
-              let geometry = chart.geoJson.features[i].geometry;
-              let props = chart.geoJson.features[i].properties;
+              const geometry = chart.geoJson.features[i].geometry;
+              const props = chart.geoJson.features[i].properties;
               expect(props.center).to.eql(geometry.coordinates.slice(0).reverse());
             });
           });
 
           it('should handle both AggConfig and non-AggConfig results', function () {
             table.rows.forEach(function (row, i) {
-              let props = chart.geoJson.features[i].properties;
+              const props = chart.geoJson.features[i].properties;
               if (tableOpts.asAggConfigResults) {
                 expect(props.aggConfigResult).to.be(row[metricColI]);
                 expect(props.value).to.be(row[metricColI].value);
diff --git a/src/ui/public/agg_response/geo_json/_tooltip_formatter.js b/src/ui/public/agg_response/geo_json/_tooltip_formatter.js
index f444d5b27d0d5..23db29ff6622d 100644
--- a/src/ui/public/agg_response/geo_json/_tooltip_formatter.js
+++ b/src/ui/public/agg_response/geo_json/_tooltip_formatter.js
@@ -3,19 +3,19 @@ import _ from 'lodash';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function TileMapTooltipFormatter($compile, $rootScope, Private) {
 
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
-  let $tooltipScope = $rootScope.$new();
-  let $el = $('<div>').html(require('ui/agg_response/geo_json/_tooltip.html'));
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
+  const $tooltipScope = $rootScope.$new();
+  const $el = $('<div>').html(require('ui/agg_response/geo_json/_tooltip.html'));
   $compile($el)($tooltipScope);
 
   return function tooltipFormatter(feature) {
     if (!feature) return '';
 
-    let value = feature.properties.value;
-    let acr = feature.properties.aggConfigResult;
-    let vis = acr.aggConfig.vis;
+    const value = feature.properties.value;
+    const acr = feature.properties.aggConfigResult;
+    const vis = acr.aggConfig.vis;
 
-    let metricAgg = acr.aggConfig;
+    const metricAgg = acr.aggConfig;
     let geoFormat = _.get(vis.aggs, 'byTypeName.geohash_grid[0].format');
     if (!geoFormat) geoFormat = fieldFormats.getDefaultInstance('geo_point');
 
diff --git a/src/ui/public/agg_response/geo_json/geo_json.js b/src/ui/public/agg_response/geo_json/geo_json.js
index aac0fba222985..fe7018aee29a5 100644
--- a/src/ui/public/agg_response/geo_json/geo_json.js
+++ b/src/ui/public/agg_response/geo_json/geo_json.js
@@ -3,7 +3,7 @@ import rowsToFeatures from 'ui/agg_response/geo_json/rows_to_features';
 import AggResponseGeoJsonTooltipFormatterProvider from 'ui/agg_response/geo_json/_tooltip_formatter';
 export default function TileMapConverterFn(Private, timefilter, $compile, $rootScope) {
 
-  let tooltipFormatter = Private(AggResponseGeoJsonTooltipFormatterProvider);
+  const tooltipFormatter = Private(AggResponseGeoJsonTooltipFormatterProvider);
 
   return function (vis, table) {
 
@@ -13,13 +13,13 @@ export default function TileMapConverterFn(Private, timefilter, $compile, $rootS
       });
     }
 
-    let geoI = columnIndex('segment');
-    let metricI = columnIndex('metric');
-    let geoAgg = _.get(table.columns, [geoI, 'aggConfig']);
-    let metricAgg = _.get(table.columns, [metricI, 'aggConfig']);
+    const geoI = columnIndex('segment');
+    const metricI = columnIndex('metric');
+    const geoAgg = _.get(table.columns, [geoI, 'aggConfig']);
+    const metricAgg = _.get(table.columns, [metricI, 'aggConfig']);
 
-    let features = rowsToFeatures(table, geoI, metricI);
-    let values = features.map(function (feature) {
+    const features = rowsToFeatures(table, geoI, metricI);
+    const values = features.map(function (feature) {
       return feature.properties.value;
     });
 
diff --git a/src/ui/public/agg_response/geo_json/rows_to_features.js b/src/ui/public/agg_response/geo_json/rows_to_features.js
index 634bfd26b5335..38e2757a50466 100644
--- a/src/ui/public/agg_response/geo_json/rows_to_features.js
+++ b/src/ui/public/agg_response/geo_json/rows_to_features.js
@@ -12,19 +12,19 @@ function unwrap(val) {
 
 function convertRowsToFeatures(table, geoI, metricI) {
   return _.transform(table.rows, function (features, row) {
-    let geohash = unwrap(row[geoI]);
+    const geohash = unwrap(row[geoI]);
     if (!geohash) return;
 
     // fetch latLn of northwest and southeast corners, and center point
-    let location = decodeGeoHash(geohash);
+    const location = decodeGeoHash(geohash);
 
-    let centerLatLng = [
+    const centerLatLng = [
       location.latitude[2],
       location.longitude[2]
     ];
 
     // order is nw, ne, se, sw
-    let rectangle = [
+    const rectangle = [
       [location.latitude[0], location.longitude[0]],
       [location.latitude[0], location.longitude[1]],
       [location.latitude[1], location.longitude[1]],
diff --git a/src/ui/public/agg_response/hierarchical/__tests__/build_hierarchical_data.js b/src/ui/public/agg_response/hierarchical/__tests__/build_hierarchical_data.js
index a5e5555c81243..fcf91a9518d74 100644
--- a/src/ui/public/agg_response/hierarchical/__tests__/build_hierarchical_data.js
+++ b/src/ui/public/agg_response/hierarchical/__tests__/build_hierarchical_data.js
@@ -35,7 +35,7 @@ describe('buildHierarchicalData', function () {
     let results;
 
     beforeEach(function () {
-      let id = 1;
+      const id = 1;
       vis = new Vis(indexPattern, {
         type: 'pie',
         aggs: [
@@ -48,7 +48,7 @@ describe('buildHierarchicalData', function () {
     });
 
     it('should set the slices with one child to a consistent label', function () {
-      let checkLabel = 'Count';
+      const checkLabel = 'Count';
       expect(results).to.have.property('slices');
       expect(results.slices).to.have.property('children');
       expect(results.slices.children).to.have.length(1);
@@ -68,7 +68,7 @@ describe('buildHierarchicalData', function () {
 
     it('should set the rows', function () {
       let id = 1;
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'pie',
         aggs: [
           { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
@@ -79,13 +79,13 @@ describe('buildHierarchicalData', function () {
       });
       // We need to set the aggs to a known value.
       _.each(vis.aggs, function (agg) { agg.id = 'agg_' + id++; });
-      let results = buildHierarchicalData(vis, fixtures.threeTermBuckets);
+      const results = buildHierarchicalData(vis, fixtures.threeTermBuckets);
       expect(results).to.have.property('rows');
     });
 
     it('should set the columns', function () {
       let id = 1;
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'pie',
         aggs: [
           { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
@@ -96,7 +96,7 @@ describe('buildHierarchicalData', function () {
       });
       // We need to set the aggs to a known value.
       _.each(vis.aggs, function (agg) { agg.id = 'agg_' + id++; });
-      let results = buildHierarchicalData(vis, fixtures.threeTermBuckets);
+      const results = buildHierarchicalData(vis, fixtures.threeTermBuckets);
       expect(results).to.have.property('columns');
     });
 
@@ -281,7 +281,7 @@ describe('buildHierarchicalData', function () {
     });
 
     it('should set the hits attribute for the results', function () {
-      let errCall = Notifier.prototype.error.getCall(0);
+      const errCall = Notifier.prototype.error.getCall(0);
       expect(errCall).to.be.ok();
       expect(errCall.args[0]).to.contain('not supported');
 
diff --git a/src/ui/public/agg_response/hierarchical/__tests__/collect_branch.js b/src/ui/public/agg_response/hierarchical/__tests__/collect_branch.js
index d153e7d4afc34..43ec8c84bbdf4 100644
--- a/src/ui/public/agg_response/hierarchical/__tests__/collect_branch.js
+++ b/src/ui/public/agg_response/hierarchical/__tests__/collect_branch.js
@@ -4,7 +4,7 @@ import collectBranch from 'ui/agg_response/hierarchical/_collect_branch';
 import expect from 'expect.js';
 describe('collectBranch()', function () {
   let results;
-  let convert = function (name) {
+  const convert = function (name) {
     return 'converted:' + name;
   };
 
diff --git a/src/ui/public/agg_response/hierarchical/__tests__/create_raw_data.js b/src/ui/public/agg_response/hierarchical/__tests__/create_raw_data.js
index f42e4442c4fd1..0a99fd9142198 100644
--- a/src/ui/public/agg_response/hierarchical/__tests__/create_raw_data.js
+++ b/src/ui/public/agg_response/hierarchical/__tests__/create_raw_data.js
@@ -37,7 +37,7 @@ describe('buildHierarchicalData()', function () {
           { type: 'terms', schema: 'segment', params: { field: 'geo.src' }}
         ]
       });
-      let buckets = arrayToLinkedList(vis.aggs.bySchemaGroup.buckets);
+      const buckets = arrayToLinkedList(vis.aggs.bySchemaGroup.buckets);
       // We need to set the aggs to a known value.
       _.each(vis.aggs, function (agg) { agg.id = 'agg_' + id++; });
       results = createRawData(vis, fixtures.threeTermBuckets);
@@ -48,7 +48,7 @@ describe('buildHierarchicalData()', function () {
       expect(results.columns).to.have.length(6);
       _.each(results.columns, function (column) {
         expect(column).to.have.property('aggConfig');
-        let agg = column.aggConfig;
+        const agg = column.aggConfig;
         expect(column).to.have.property('categoryName', agg.schema.name);
         expect(column).to.have.property('id', agg.id);
         expect(column).to.have.property('aggType', agg.type);
diff --git a/src/ui/public/agg_response/hierarchical/__tests__/extract_buckets.js b/src/ui/public/agg_response/hierarchical/__tests__/extract_buckets.js
index 8d2a45c3a1f45..59c20a8e518df 100644
--- a/src/ui/public/agg_response/hierarchical/__tests__/extract_buckets.js
+++ b/src/ui/public/agg_response/hierarchical/__tests__/extract_buckets.js
@@ -7,14 +7,14 @@ describe('buildHierarchicalData()', function () {
 
     it('should normalize a bucket object into an array', function () {
 
-      let bucket = {
+      const bucket = {
         buckets: {
           foo: { doc_count: 1 },
           bar: { doc_count: 2 }
         }
       };
 
-      let buckets = extractBuckets(bucket);
+      const buckets = extractBuckets(bucket);
       expect(buckets).to.be.an(Array);
       expect(buckets).to.have.length(2);
       expect(buckets[0]).to.have.property('key', 'foo');
@@ -24,19 +24,19 @@ describe('buildHierarchicalData()', function () {
     });
 
     it('should return an empty array for undefined buckets', function () {
-      let buckets = extractBuckets();
+      const buckets = extractBuckets();
       expect(buckets).to.be.an(Array);
       expect(buckets).to.have.length(0);
     });
 
     it('should return the bucket array', function () {
-      let bucket =  {
+      const bucket =  {
         buckets: [
           { key: 'foo', doc_count: 1 },
           { key: 'bar', doc_count: 2 }
         ]
       };
-      let buckets = extractBuckets(bucket);
+      const buckets = extractBuckets(bucket);
       expect(buckets).to.be.an(Array);
       expect(buckets).to.be(bucket.buckets);
     });
diff --git a/src/ui/public/agg_response/hierarchical/__tests__/transform_aggregation.js b/src/ui/public/agg_response/hierarchical/__tests__/transform_aggregation.js
index 97adf8ea4073b..d927ef738f4d7 100644
--- a/src/ui/public/agg_response/hierarchical/__tests__/transform_aggregation.js
+++ b/src/ui/public/agg_response/hierarchical/__tests__/transform_aggregation.js
@@ -42,17 +42,17 @@ describe('buildHierarchicalData()', function () {
     });
 
     it('relies on metricAgg#getValue() for the size of the children', function () {
-      let aggData = {
+      const aggData = {
         buckets: [
           { key: 'foo' },
           { key: 'bar' }
         ]
       };
 
-      let football = {};
+      const football = {};
       fixture.metric.getValue = _.constant(football);
 
-      let children = transform(fixture.agg, fixture.metric, aggData);
+      const children = transform(fixture.agg, fixture.metric, aggData);
       expect(children).to.be.an(Array);
       expect(children).to.have.length(2);
       expect(children[0]).to.have.property('size', football);
@@ -60,7 +60,7 @@ describe('buildHierarchicalData()', function () {
     });
 
     it('should create two levels of metrics', function () {
-      let children = transform(fixture.agg, fixture.metric, fixture.aggData);
+      const children = transform(fixture.agg, fixture.metric, fixture.aggData);
       fixture.metric.getValue = function (b) { return b.doc_count; };
 
       expect(children).to.be.an(Array);
diff --git a/src/ui/public/agg_response/hierarchical/_build_split.js b/src/ui/public/agg_response/hierarchical/_build_split.js
index f4eb0fdf764ab..4cb52e7418a45 100644
--- a/src/ui/public/agg_response/hierarchical/_build_split.js
+++ b/src/ui/public/agg_response/hierarchical/_build_split.js
@@ -1,10 +1,10 @@
 import collectKeys from 'ui/agg_response/hierarchical/_collect_keys';
 import AggResponseHierarchicalTransformAggregationProvider from 'ui/agg_response/hierarchical/_transform_aggregation';
 export default function biuldSplitProvider(Private) {
-  let transformer = Private(AggResponseHierarchicalTransformAggregationProvider);
+  const transformer = Private(AggResponseHierarchicalTransformAggregationProvider);
   return function (agg, metric, aggData) {
     // Ceate the split structure
-    let split = { label: '', slices: { children: [] } };
+    const split = { label: '', slices: { children: [] } };
 
     // Transform the aggData into splits
     split.slices.children = transformer(agg, metric, aggData);
diff --git a/src/ui/public/agg_response/hierarchical/_collect_branch.js b/src/ui/public/agg_response/hierarchical/_collect_branch.js
index 5ad6518388278..743ff469532f1 100644
--- a/src/ui/public/agg_response/hierarchical/_collect_branch.js
+++ b/src/ui/public/agg_response/hierarchical/_collect_branch.js
@@ -3,13 +3,13 @@ define(function () {
     // walk up the branch for each parent
     function walk(item, memo) {
       // record the the depth
-      let depth = item.depth - 1;
+      const depth = item.depth - 1;
 
       // Using the aggConfig determine what the field name is. If the aggConfig
       // doesn't exist (which means it's an _all agg) then use the level for
       // the field name
-      let col = item.aggConfig;
-      let field = (col && col.params && col.params.field && col.params.field.displayName)
+      const col = item.aggConfig;
+      const field = (col && col.params && col.params.field && col.params.field.displayName)
         || (col && col.label)
         || ('level ' + item.depth);
 
diff --git a/src/ui/public/agg_response/hierarchical/_collect_keys.js b/src/ui/public/agg_response/hierarchical/_collect_keys.js
index 1b9a542462c75..aa43871365ea6 100644
--- a/src/ui/public/agg_response/hierarchical/_collect_keys.js
+++ b/src/ui/public/agg_response/hierarchical/_collect_keys.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 export default function collectKeys(children) {
-  let nextChildren = _.pluck(children, 'children');
-  let keys = _.pluck(children, 'name');
+  const nextChildren = _.pluck(children, 'children');
+  const keys = _.pluck(children, 'name');
   return _(nextChildren)
   .map(collectKeys)
   .flattenDeep()
diff --git a/src/ui/public/agg_response/hierarchical/_create_raw_data.js b/src/ui/public/agg_response/hierarchical/_create_raw_data.js
index 93b9c1b519bfe..ccf9077b1994b 100644
--- a/src/ui/public/agg_response/hierarchical/_create_raw_data.js
+++ b/src/ui/public/agg_response/hierarchical/_create_raw_data.js
@@ -3,12 +3,12 @@ import extractBuckets from 'ui/agg_response/hierarchical/_extract_buckets';
 export default function (vis, resp) {
 
   // Create the initial results structure
-  let results = { rows: [] };
+  const results = { rows: [] };
 
   // Create a reference to the buckets and metrics
-  let metrics = vis.aggs.bySchemaGroup.metrics;
-  let buckets = vis.aggs.bySchemaGroup.buckets;
-  let aggs = [];
+  const metrics = vis.aggs.bySchemaGroup.metrics;
+  const buckets = vis.aggs.bySchemaGroup.buckets;
+  const aggs = [];
 
   if (buckets) {
     _.each(buckets, function (bucket) {
@@ -37,7 +37,7 @@ export default function (vis, resp) {
 
   // if there are no buckets then we need to just set the value and return
   if (!buckets) {
-    let value = resp.aggregations
+    const value = resp.aggregations
       && resp.aggregations[metrics[0].id]
       && resp.aggregations[metrics[0].id].value
       || resp.hits.total;
@@ -60,7 +60,7 @@ export default function (vis, resp) {
     // iterate through all the buckets
     _.each(extractBuckets(data[agg.id], agg), function (bucket) {
 
-      let _record = _.flattenDeep([record, bucket.key]);
+      const _record = _.flattenDeep([record, bucket.key]);
       _.each(metrics, function (metric) {
         let value = bucket.doc_count;
         if (bucket[metric.id] && !_.isUndefined(bucket[metric.id].value)) {
@@ -73,7 +73,7 @@ export default function (vis, resp) {
       // buckets. If it does then we need to keep on walking the tree.
       // This is where the recursion happens.
       if (agg._next) {
-        let nextBucket = bucket[agg._next.id];
+        const nextBucket = bucket[agg._next.id];
         if (nextBucket && nextBucket.buckets) {
           walkBuckets(agg._next, bucket, _record);
         }
diff --git a/src/ui/public/agg_response/hierarchical/_extract_buckets.js b/src/ui/public/agg_response/hierarchical/_extract_buckets.js
index e80f408664535..b496bece578aa 100644
--- a/src/ui/public/agg_response/hierarchical/_extract_buckets.js
+++ b/src/ui/public/agg_response/hierarchical/_extract_buckets.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 export default function (bucket, agg) {
   if (bucket && _.isPlainObject(bucket.buckets)) {
     return _.map(bucket.buckets, function (value, key) {
-      let item = _.cloneDeep(value);
+      const item = _.cloneDeep(value);
       item.key = agg ? agg.getKey(value, key) : key;
       return item;
     });
diff --git a/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js b/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js
index f4acab3927a57..113cf8259f4c7 100644
--- a/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js
+++ b/src/ui/public/agg_response/hierarchical/_hierarchical_tooltip_formatter.js
@@ -3,19 +3,19 @@ import $ from 'jquery';
 import collectBranch from 'ui/agg_response/hierarchical/_collect_branch';
 import numeral from 'numeral';
 export default function HierarchicalTooltipFormaterProvider($rootScope, $compile, $sce) {
-  let $tooltip = $(require('ui/agg_response/hierarchical/_tooltip.html'));
-  let $tooltipScope = $rootScope.$new();
+  const $tooltip = $(require('ui/agg_response/hierarchical/_tooltip.html'));
+  const $tooltipScope = $rootScope.$new();
 
   $compile($tooltip)($tooltipScope);
 
   return function (columns) {
     return function (event) {
-      let datum = event.datum;
+      const datum = event.datum;
 
       // Collect the current leaf and parents into an array of values
       $tooltipScope.rows = collectBranch(datum);
 
-      let metricCol = $tooltipScope.metricCol = _.find(columns, { categoryName: 'metric' });
+      const metricCol = $tooltipScope.metricCol = _.find(columns, { categoryName: 'metric' });
 
       // Map those values to what the tooltipSource.rows format.
       _.forEachRight($tooltipScope.rows, function (row, i, rows) {
diff --git a/src/ui/public/agg_response/hierarchical/_transform_aggregation.js b/src/ui/public/agg_response/hierarchical/_transform_aggregation.js
index a176f2d3e0154..fda5791ab8559 100644
--- a/src/ui/public/agg_response/hierarchical/_transform_aggregation.js
+++ b/src/ui/public/agg_response/hierarchical/_transform_aggregation.js
@@ -4,14 +4,14 @@ import AggConfigResult from 'ui/vis/agg_config_result';
 export default function transformAggregationProvider(Private) {
   return function transformAggregation(agg, metric, aggData, parent) {
     return _.map(extractBuckets(aggData, agg), function (bucket) {
-      let aggConfigResult = new AggConfigResult(
+      const aggConfigResult = new AggConfigResult(
         agg,
         parent && parent.aggConfigResult,
         metric.getValue(bucket),
         agg.getKey(bucket)
       );
 
-      let branch = {
+      const branch = {
         name: agg.fieldFormatter()(bucket.key),
         size: aggConfigResult.value,
         aggConfig: agg,
@@ -27,7 +27,7 @@ export default function transformAggregationProvider(Private) {
       // If the next bucket exists and it has children the we need to
       // transform it as well. This is where the recursion happens.
       if (agg._next) {
-        let nextBucket = bucket[agg._next.id];
+        const nextBucket = bucket[agg._next.id];
         if (nextBucket && nextBucket.buckets) {
           branch.children = transformAggregation(agg._next, metric, nextBucket, branch);
         }
diff --git a/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js b/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js
index 32c782bf6622e..b851054598ba4 100644
--- a/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js
+++ b/src/ui/public/agg_response/hierarchical/build_hierarchical_data.js
@@ -6,11 +6,11 @@ import AggConfigResult from 'ui/vis/agg_config_result';
 import AggResponseHierarchicalBuildSplitProvider from 'ui/agg_response/hierarchical/_build_split';
 import AggResponseHierarchicalHierarchicalTooltipFormatterProvider from 'ui/agg_response/hierarchical/_hierarchical_tooltip_formatter';
 export default function buildHierarchicalDataProvider(Private, Notifier) {
-  let buildSplit = Private(AggResponseHierarchicalBuildSplitProvider);
-  let tooltipFormatter = Private(AggResponseHierarchicalHierarchicalTooltipFormatterProvider);
+  const buildSplit = Private(AggResponseHierarchicalBuildSplitProvider);
+  const tooltipFormatter = Private(AggResponseHierarchicalHierarchicalTooltipFormatterProvider);
 
 
-  let notify = new Notifier({
+  const notify = new Notifier({
     location: 'Pie chart response converter'
   });
 
@@ -21,19 +21,19 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
 
     // Find the metric so it's easier to reference.
     // TODO: Change this to support multiple metrics.
-    let metric = vis.aggs.bySchemaGroup.metrics[0];
+    const metric = vis.aggs.bySchemaGroup.metrics[0];
 
     // Link each agg to the next agg. This will be
     // to identify the next bucket aggregation
     buckets = arrayToLinkedList(buckets);
 
     // Create the raw data to be used in the spy panel
-    let raw = createRawData(vis, resp);
+    const raw = createRawData(vis, resp);
 
     // If buckets is falsy then we should just return the aggs
     if (!buckets) {
-      let label = 'Count';
-      let value = resp.aggregations
+      const label = 'Count';
+      const value = resp.aggregations
         && resp.aggregations[metric.id]
         && resp.aggregations[metric.id].value
         || resp.hits.total;
@@ -50,8 +50,8 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
       };
     }
 
-    let firstAgg = buckets[0];
-    let aggData = resp.aggregations[firstAgg.id];
+    const firstAgg = buckets[0];
+    const aggData = resp.aggregations[firstAgg.id];
 
     if (!firstAgg._next && firstAgg.schema.name === 'split') {
       notify.error('Splitting charts without splitting slices is not supported. Pretending that we are just splitting slices.');
@@ -59,7 +59,7 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
 
     // start with splitting slices
     if (!firstAgg._next || firstAgg.schema.name === 'segment') {
-      let split = buildSplit(firstAgg, metric, aggData);
+      const split = buildSplit(firstAgg, metric, aggData);
       split.hits = resp.hits.total;
       split.raw = raw;
       split.tooltipFormatter = tooltipFormatter(raw.columns);
@@ -67,17 +67,17 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
     }
 
     // map the split aggregations into rows.
-    let rows = _.map(extractBuckets(aggData, firstAgg), function (bucket) {
-      let agg = firstAgg._next;
-      let split = buildSplit(agg, metric, bucket[agg.id]);
+    const rows = _.map(extractBuckets(aggData, firstAgg), function (bucket) {
+      const agg = firstAgg._next;
+      const split = buildSplit(agg, metric, bucket[agg.id]);
       // Since splits display labels we need to set it.
       split.label = firstAgg.fieldFormatter()(agg.getKey(bucket));
 
-      let displayName = firstAgg.fieldDisplayName();
+      const displayName = firstAgg.fieldDisplayName();
       if (!_.isEmpty(displayName)) split.label += ': ' + displayName;
 
       split.tooltipFormatter = tooltipFormatter(raw.columns);
-      let aggConfigResult = new AggConfigResult(firstAgg, null, null, firstAgg.getKey(bucket));
+      const aggConfigResult = new AggConfigResult(firstAgg, null, null, firstAgg.getKey(bucket));
       split.split = { aggConfig: firstAgg, aggConfigResult: aggConfigResult, key: bucket.key };
       _.each(split.slices.children, function (child) {
         child.aggConfigResult.$parent = aggConfigResult;
@@ -85,7 +85,7 @@ export default function buildHierarchicalDataProvider(Private, Notifier) {
       return split;
     });
 
-    let result = { hits: resp.hits.total, raw: raw };
+    const result = { hits: resp.hits.total, raw: raw };
     if (firstAgg.params.row) {
       result.rows = rows;
     } else {
diff --git a/src/ui/public/agg_response/point_series/__tests__/_add_to_siri.js b/src/ui/public/agg_response/point_series/__tests__/_add_to_siri.js
index 4e9c563f78dbf..c07780bfbf0a2 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_add_to_siri.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_add_to_siri.js
@@ -10,9 +10,9 @@ describe('addToSiri', function () {
   }));
 
   it('creates a new series the first time it sees an id', function () {
-    let series = new Map();
-    let point = {};
-    let id = 'id';
+    const series = new Map();
+    const point = {};
+    const id = 'id';
     addToSiri(series, point, id);
 
     expect(series.has(id)).to.be(true);
@@ -23,13 +23,13 @@ describe('addToSiri', function () {
   });
 
   it('adds points to existing series if id has been seen', function () {
-    let series = new Map();
-    let id = 'id';
+    const series = new Map();
+    const id = 'id';
 
-    let point = {};
+    const point = {};
     addToSiri(series, point, id);
 
-    let point2 = {};
+    const point2 = {};
     addToSiri(series, point2, id);
 
     expect(series.has(id)).to.be(true);
@@ -41,10 +41,10 @@ describe('addToSiri', function () {
   });
 
   it('allows overriding the series label', function () {
-    let series = new Map();
-    let id = 'id';
-    let label = 'label';
-    let point = {};
+    const series = new Map();
+    const id = 'id';
+    const label = 'label';
+    const point = {};
     addToSiri(series, point, id, label);
 
     expect(series.has(id)).to.be(true);
diff --git a/src/ui/public/agg_response/point_series/__tests__/_fake_x_aspect.js b/src/ui/public/agg_response/point_series/__tests__/_fake_x_aspect.js
index 501631e1c921a..1b1661186b2be 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_fake_x_aspect.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_fake_x_aspect.js
@@ -22,8 +22,8 @@ describe('makeFakeXAspect', function () {
   }));
 
   it('creates an object that looks like an aspect', function () {
-    let vis = new Vis(indexPattern, { type: 'histogram' });
-    let aspect = makeFakeXAspect(vis);
+    const vis = new Vis(indexPattern, { type: 'histogram' });
+    const aspect = makeFakeXAspect(vis);
 
     expect(aspect)
       .to.have.property('i', -1)
diff --git a/src/ui/public/agg_response/point_series/__tests__/_get_aspects.js b/src/ui/public/agg_response/point_series/__tests__/_get_aspects.js
index e1bf5ce07a702..ef4e7079c9e81 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_get_aspects.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_get_aspects.js
@@ -27,7 +27,7 @@ describe('getAspects', function () {
   let vis;
   let table;
 
-  let date = _.memoize(function (n) {
+  const date = _.memoize(function (n) {
     return moment().startOf('day').add(n, 'hour').valueOf();
   });
 
@@ -50,7 +50,7 @@ describe('getAspects', function () {
 
   function init(group, x, y) {
     // map args to indicies that should be removed
-    let filter = filterByIndex([
+    const filter = filterByIndex([
       x > 0,
       x > 1,
       group > 0,
@@ -92,7 +92,7 @@ describe('getAspects', function () {
       ].map(filter)
     };
 
-    let aggs = vis.aggs.splice(0, vis.aggs.length);
+    const aggs = vis.aggs.splice(0, vis.aggs.length);
     filter(aggs).forEach(function (filter) {
       vis.aggs.push(filter);
     });
@@ -101,7 +101,7 @@ describe('getAspects', function () {
   it('produces an aspect object for each of the aspect types found in the columns', function () {
     init(1, 1, 1);
 
-    let aspects = getAspects(vis, table);
+    const aspects = getAspects(vis, table);
     validate(aspects.x, 0);
     validate(aspects.series, 1);
     validate(aspects.y, 2);
@@ -110,7 +110,7 @@ describe('getAspects', function () {
   it('uses arrays only when there are more than one aspect of a specific type', function () {
     init(0, 1, 2);
 
-    let aspects = getAspects(vis, table);
+    const aspects = getAspects(vis, table);
 
     validate(aspects.x, 0);
     expect(aspects.series == null).to.be(true);
@@ -139,7 +139,7 @@ describe('getAspects', function () {
   it('creates a fake x aspect if the column does not exist', function () {
     init(0, 0, 1);
 
-    let aspects = getAspects(vis, table);
+    const aspects = getAspects(vis, table);
 
     expect(aspects.x)
       .to.be.an('object')
diff --git a/src/ui/public/agg_response/point_series/__tests__/_get_point.js b/src/ui/public/agg_response/point_series/__tests__/_get_point.js
index 1017a5f020cd1..30088025961d8 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_get_point.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_get_point.js
@@ -7,8 +7,8 @@ describe('getPoint', function () {
 
   let getPoint;
 
-  let truthFormatted = { fieldFormatter: _.constant(_.constant(true)) };
-  let identFormatted = { fieldFormatter: _.constant(_.identity) };
+  const truthFormatted = { fieldFormatter: _.constant(_.constant(true)) };
+  const identFormatted = { fieldFormatter: _.constant(_.identity) };
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function (Private) {
@@ -29,9 +29,9 @@ describe('getPoint', function () {
     });
 
     it('properly unwraps and scales values', function () {
-      let row = [ { value: 1 }, { value: 2 }, { value: 3 } ];
-      let zAspect = { i: 2 };
-      let point = getPoint(xAspect, seriesAspect, yScale, row, yAspect, zAspect);
+      const row = [ { value: 1 }, { value: 2 }, { value: 3 } ];
+      const zAspect = { i: 2 };
+      const point = getPoint(xAspect, seriesAspect, yScale, row, yAspect, zAspect);
 
       expect(point)
         .to.have.property('x', 1)
@@ -42,8 +42,8 @@ describe('getPoint', function () {
     });
 
     it('ignores points with a y value of NaN', function () {
-      let row = [ { value: 1 }, { value: 'NaN' }];
-      let point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
+      const row = [ { value: 1 }, { value: 'NaN' }];
+      const point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
       expect(point).to.be(void 0);
     });
   });
@@ -62,8 +62,8 @@ describe('getPoint', function () {
     });
 
     it('properly unwraps and scales values', function () {
-      let seriesAspect = { i: 1, agg: identFormatted };
-      let point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
+      const seriesAspect = { i: 1, agg: identFormatted };
+      const point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
 
       expect(point)
         .to.have.property('x', 1)
@@ -73,8 +73,8 @@ describe('getPoint', function () {
     });
 
     it('properly formats series values', function () {
-      let seriesAspect = { i: 1, agg: truthFormatted };
-      let point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
+      const seriesAspect = { i: 1, agg: truthFormatted };
+      const point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
 
       expect(point)
         .to.have.property('x', 1)
@@ -84,8 +84,8 @@ describe('getPoint', function () {
     });
 
     it ('adds the aggConfig to the points', function () {
-      let seriesAspect = { i: 1, agg:  truthFormatted};
-      let point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
+      const seriesAspect = { i: 1, agg:  truthFormatted};
+      const point = getPoint(xAspect, seriesAspect, yScale, row, yAspect);
 
       expect(point).to.have.property('aggConfig', truthFormatted);
     });
diff --git a/src/ui/public/agg_response/point_series/__tests__/_get_series.js b/src/ui/public/agg_response/point_series/__tests__/_get_series.js
index b09fd319624fd..834df70375610 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_get_series.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_get_series.js
@@ -5,7 +5,7 @@ import AggResponsePointSeriesGetSeriesProvider from 'ui/agg_response/point_serie
 describe('getSeries', function () {
   let getSeries;
 
-  let agg = { fieldFormatter: _.constant(_.identity) };
+  const agg = { fieldFormatter: _.constant(_.identity) };
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function (Private) {
@@ -19,7 +19,7 @@ describe('getSeries', function () {
   }
 
   it('produces a single series with points for each row', function () {
-    let rows = [
+    const rows = [
       [1, 2, 3],
       [1, 2, 3],
       [1, 2, 3],
@@ -27,7 +27,7 @@ describe('getSeries', function () {
       [1, 2, 3]
     ].map(wrapRows);
 
-    let chart = {
+    const chart = {
       aspects: {
         x: { i: 0 },
         y: { i: 1 },
@@ -35,13 +35,13 @@ describe('getSeries', function () {
       }
     };
 
-    let series = getSeries(rows, chart);
+    const series = getSeries(rows, chart);
 
     expect(series)
       .to.be.an('array')
       .and.to.have.length(1);
 
-    let siri = series[0];
+    const siri = series[0];
     expect(siri)
       .to.be.an('object')
       .and.have.property('label', '')
@@ -60,7 +60,7 @@ describe('getSeries', function () {
   });
 
   it('produces multiple series if there are multiple y aspects', function () {
-    let rows = [
+    const rows = [
       [1, 2, 3],
       [1, 2, 3],
       [1, 2, 3],
@@ -68,7 +68,7 @@ describe('getSeries', function () {
       [1, 2, 3]
     ].map(wrapRows);
 
-    let chart = {
+    const chart = {
       aspects: {
         x: { i: 0 },
         y: [
@@ -78,7 +78,7 @@ describe('getSeries', function () {
       }
     };
 
-    let series = getSeries(rows, chart);
+    const series = getSeries(rows, chart);
 
     expect(series)
       .to.be.an('array')
@@ -103,7 +103,7 @@ describe('getSeries', function () {
   });
 
   it('produces multiple series if there is a series aspect', function () {
-    let rows = [
+    const rows = [
       ['0', 3],
       ['1', 3],
       ['1', 'NaN'],
@@ -114,7 +114,7 @@ describe('getSeries', function () {
       ['1', 3]
     ].map(wrapRows);
 
-    let chart = {
+    const chart = {
       aspects: {
         x: { i: -1 },
         series: { i: 0, agg: agg },
@@ -122,7 +122,7 @@ describe('getSeries', function () {
       }
     };
 
-    let series = getSeries(rows, chart);
+    const series = getSeries(rows, chart);
 
     expect(series)
       .to.be.an('array')
@@ -147,7 +147,7 @@ describe('getSeries', function () {
   });
 
   it('produces multiple series if there is a series aspect and multipl y aspects', function () {
-    let rows = [
+    const rows = [
       ['0', 3, 4],
       ['1', 3, 4],
       ['0', 3, 4],
@@ -156,7 +156,7 @@ describe('getSeries', function () {
       ['1', 3, 4]
     ].map(wrapRows);
 
-    let chart = {
+    const chart = {
       aspects: {
         x: { i: -1 },
         series: { i: 0, agg: agg },
@@ -167,7 +167,7 @@ describe('getSeries', function () {
       }
     };
 
-    let series = getSeries(rows, chart);
+    const series = getSeries(rows, chart);
 
     expect(series)
       .to.be.an('array')
@@ -197,7 +197,7 @@ describe('getSeries', function () {
   });
 
   it('produces a series list in the same order as its corresponding metric column', function () {
-    let rows = [
+    const rows = [
       ['0', 3, 4],
       ['1', 3, 4],
       ['0', 3, 4],
@@ -206,7 +206,7 @@ describe('getSeries', function () {
       ['1', 3, 4]
     ].map(wrapRows);
 
-    let chart = {
+    const chart = {
       aspects: {
         x: { i: -1 },
         series: { i: 0, agg: agg },
@@ -217,7 +217,7 @@ describe('getSeries', function () {
       }
     };
 
-    let series = getSeries(rows, chart);
+    const series = getSeries(rows, chart);
     expect(series[0]).to.have.property('label', '0: 0');
     expect(series[1]).to.have.property('label', '0: 1');
     expect(series[2]).to.have.property('label', '1: 0');
@@ -230,7 +230,7 @@ describe('getSeries', function () {
       y.i = i;
     });
 
-    let series2 = getSeries(rows, chart);
+    const series2 = getSeries(rows, chart);
     expect(series2[0]).to.have.property('label', '0: 1');
     expect(series2[1]).to.have.property('label', '0: 0');
     expect(series2[2]).to.have.property('label', '1: 1');
diff --git a/src/ui/public/agg_response/point_series/__tests__/_init_x_axis.js b/src/ui/public/agg_response/point_series/__tests__/_init_x_axis.js
index 974afab294831..9c2cfb9ef0890 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_init_x_axis.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_init_x_axis.js
@@ -11,7 +11,7 @@ describe('initXAxis', function () {
     initXAxis = Private(AggResponsePointSeriesInitXAxisProvider);
   }));
 
-  let baseChart = {
+  const baseChart = {
     aspects: {
       x: {
         agg: {
@@ -27,7 +27,7 @@ describe('initXAxis', function () {
   };
 
   it('sets the xAxisFormatter if the agg is not ordered', function () {
-    let chart = _.cloneDeep(baseChart);
+    const chart = _.cloneDeep(baseChart);
     initXAxis(chart);
     expect(chart)
       .to.have.property('xAxisLabel', 'label')
@@ -35,7 +35,7 @@ describe('initXAxis', function () {
   });
 
   it('makes the chart ordered if the agg is ordered', function () {
-    let chart = _.cloneDeep(baseChart);
+    const chart = _.cloneDeep(baseChart);
     chart.aspects.x.agg.type.ordered = true;
 
     initXAxis(chart);
@@ -50,7 +50,7 @@ describe('initXAxis', function () {
   });
 
   it('reads the interval param from the x agg', function () {
-    let chart = _.cloneDeep(baseChart);
+    const chart = _.cloneDeep(baseChart);
     chart.aspects.x.agg.type.ordered = true;
     chart.aspects.x.agg.write = _.constant({ params: { interval: 10 } });
 
diff --git a/src/ui/public/agg_response/point_series/__tests__/_init_y_axis.js b/src/ui/public/agg_response/point_series/__tests__/_init_y_axis.js
index 97f1c98e12487..f545e3db6e0f5 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_init_y_axis.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_init_y_axis.js
@@ -19,7 +19,7 @@ describe('initYAxis', function () {
     };
   }
 
-  let baseChart = {
+  const baseChart = {
     aspects: {
       y: [
         { agg: agg(), col: { title: 'y1' } },
@@ -33,17 +33,17 @@ describe('initYAxis', function () {
   };
 
   describe('with a single y aspect', function () {
-    let singleYBaseChart = _.cloneDeep(baseChart);
+    const singleYBaseChart = _.cloneDeep(baseChart);
     singleYBaseChart.aspects.y = singleYBaseChart.aspects.y[0];
 
     it('sets the yAxisFormatter the the field formats convert fn', function () {
-      let chart = _.cloneDeep(singleYBaseChart);
+      const chart = _.cloneDeep(singleYBaseChart);
       initYAxis(chart);
       expect(chart).to.have.property('yAxisFormatter', chart.aspects.y.agg.fieldFormatter());
     });
 
     it('sets the yAxisLabel', function () {
-      let chart = _.cloneDeep(singleYBaseChart);
+      const chart = _.cloneDeep(singleYBaseChart);
       initYAxis(chart);
       expect(chart).to.have.property('yAxisLabel', 'y1');
     });
@@ -51,7 +51,7 @@ describe('initYAxis', function () {
 
   describe('with mutliple y aspects', function () {
     it('sets the yAxisFormatter the the field formats convert fn for the first y aspect', function () {
-      let chart = _.cloneDeep(baseChart);
+      const chart = _.cloneDeep(baseChart);
       initYAxis(chart);
 
       expect(chart).to.have.property('yAxisFormatter');
@@ -61,7 +61,7 @@ describe('initYAxis', function () {
     });
 
     it('does not set the yAxisLabel, it does not make sense to put multiple labels on the same axis', function () {
-      let chart = _.cloneDeep(baseChart);
+      const chart = _.cloneDeep(baseChart);
       initYAxis(chart);
       expect(chart).to.have.property('yAxisLabel', '');
     });
diff --git a/src/ui/public/agg_response/point_series/__tests__/_main.js b/src/ui/public/agg_response/point_series/__tests__/_main.js
index 8eba049940350..3ba9cdced82c8 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_main.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_main.js
@@ -25,20 +25,20 @@ describe('pointSeriesChartDataFromTable', function () {
   }));
 
   it('handles a table with just a count', function () {
-    let vis = new Vis(indexPattern, { type: 'histogram' });
-    let agg = vis.aggs[0];
-    let result = new AggConfigResult(vis.aggs[0], void 0, 100, 100);
+    const vis = new Vis(indexPattern, { type: 'histogram' });
+    const agg = vis.aggs[0];
+    const result = new AggConfigResult(vis.aggs[0], void 0, 100, 100);
 
-    let table = new Table();
+    const table = new Table();
     table.columns = [ { aggConfig: agg } ];
     table.rows.push([ result ]);
 
-    let chartData = pointSeriesChartDataFromTable(vis, table);
+    const chartData = pointSeriesChartDataFromTable(vis, table);
 
     expect(chartData).to.be.an('object');
     expect(chartData.series).to.be.an('array');
     expect(chartData.series).to.have.length(1);
-    let series = chartData.series[0];
+    const series = chartData.series[0];
     expect(series.values).to.have.length(1);
     expect(series.values[0])
       .to.have.property('x', '_all')
@@ -47,7 +47,7 @@ describe('pointSeriesChartDataFromTable', function () {
   });
 
   it('handles a table with x and y column', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         { type: 'count', schema: 'metric' },
@@ -55,32 +55,32 @@ describe('pointSeriesChartDataFromTable', function () {
       ]
     });
 
-    let y = {
+    const y = {
       agg: vis.aggs[0],
       col: { aggConfig: vis.aggs[0] },
       at: function (i) { return 100 * i; }
     };
 
-    let x = {
+    const x = {
       agg: vis.aggs[1],
       col: { aggConfig: vis.aggs[1] },
       at: function (i) { return moment().startOf('day').add(i, 'day').valueOf(); }
     };
 
-    let rowCount = 3;
-    let table = new Table();
+    const rowCount = 3;
+    const table = new Table();
     table.columns = [ x.col, y.col ];
     _.times(rowCount, function (i) {
-      let date = new AggConfigResult(x.agg, void 0, x.at(i));
+      const date = new AggConfigResult(x.agg, void 0, x.at(i));
       table.rows.push([date, new AggConfigResult(y.agg, date, y.at(i))]);
     });
 
-    let chartData = pointSeriesChartDataFromTable(vis, table);
+    const chartData = pointSeriesChartDataFromTable(vis, table);
 
     expect(chartData).to.be.an('object');
     expect(chartData.series).to.be.an('array');
     expect(chartData.series).to.have.length(1);
-    let series = chartData.series[0];
+    const series = chartData.series[0];
     expect(series.values).to.have.length(rowCount);
     series.values.forEach(function (point, i) {
       expect(point)
@@ -100,7 +100,7 @@ describe('pointSeriesChartDataFromTable', function () {
   });
 
   it('handles a table with an x and two y aspects', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
@@ -109,40 +109,40 @@ describe('pointSeriesChartDataFromTable', function () {
       ]
     });
 
-    let avg = {
+    const avg = {
       agg: vis.aggs[0],
       col: { title: 'average', aggConfig: vis.aggs[0] },
       at: function (i) { return 75.444 * (i + 1); }
     };
 
-    let date = {
+    const date = {
       agg: vis.aggs[1],
       col: { title: 'date', aggConfig: vis.aggs[1] },
       at: function (i) { return moment().startOf('day').add(i, 'day').valueOf(); }
     };
 
-    let max = {
+    const max = {
       agg: vis.aggs[2],
       col: { title: 'maximum', aggConfig: vis.aggs[2] },
       at: function (i) { return 100 * (i + 1); }
     };
 
-    let rowCount = 3;
-    let table = new Table();
+    const rowCount = 3;
+    const table = new Table();
     table.columns = [ date.col, avg.col, max.col ];
     _.times(rowCount, function (i) {
-      let dateResult = new AggConfigResult(date.agg, void 0, date.at(i));
-      let avgResult = new AggConfigResult(avg.agg, dateResult, avg.at(i));
-      let maxResult = new AggConfigResult(max.agg, dateResult, max.at(i));
+      const dateResult = new AggConfigResult(date.agg, void 0, date.at(i));
+      const avgResult = new AggConfigResult(avg.agg, dateResult, avg.at(i));
+      const maxResult = new AggConfigResult(max.agg, dateResult, max.at(i));
       table.rows.push([dateResult, avgResult, maxResult]);
     });
 
-    let chartData = pointSeriesChartDataFromTable(vis, table);
+    const chartData = pointSeriesChartDataFromTable(vis, table);
     expect(chartData).to.be.an('object');
     expect(chartData.series).to.be.an('array');
     expect(chartData.series).to.have.length(2);
     chartData.series.forEach(function (siri, i) {
-      let metric = i === 0 ? avg : max;
+      const metric = i === 0 ? avg : max;
 
       expect(siri).to.have.property('label', metric.col.label);
       expect(siri.values).to.have.length(rowCount);
@@ -170,7 +170,7 @@ describe('pointSeriesChartDataFromTable', function () {
   });
 
   it('handles a table with an x, a series, and two y aspects', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         { type: 'terms', schema: 'group', params: { field: 'extension' } },
@@ -180,53 +180,53 @@ describe('pointSeriesChartDataFromTable', function () {
       ]
     });
 
-    let extensions = ['php', 'jpg', 'gif', 'css'];
-    let term = {
+    const extensions = ['php', 'jpg', 'gif', 'css'];
+    const term = {
       agg: vis.aggs[0],
       col: { title: 'extensions', aggConfig: vis.aggs[0] },
       at: function (i) { return extensions[i % extensions.length]; }
     };
 
-    let avg = {
+    const avg = {
       agg: vis.aggs[1],
       col: { title: 'average', aggConfig: vis.aggs[1] },
       at: function (i) { return 75.444 * (i + 1); }
     };
 
-    let date = {
+    const date = {
       agg: vis.aggs[2],
       col: { title: 'date', aggConfig: vis.aggs[2] },
       at: function (i) { return moment().startOf('day').add(i, 'day').valueOf(); }
     };
 
-    let max = {
+    const max = {
       agg: vis.aggs[3],
       col: { title: 'maximum', aggConfig: vis.aggs[3] },
       at: function (i) { return 100 * (i + 1); }
     };
 
-    let metricCount = 2;
-    let rowsPerSegment = 2;
-    let rowCount = extensions.length * rowsPerSegment;
-    let table = new Table();
+    const metricCount = 2;
+    const rowsPerSegment = 2;
+    const rowCount = extensions.length * rowsPerSegment;
+    const table = new Table();
     table.columns = [ date.col, term.col, avg.col, max.col ];
     _.times(rowCount, function (i) {
-      let dateResult = new AggConfigResult(date.agg, void 0, date.at(i));
-      let termResult = new AggConfigResult(term.agg, dateResult, term.at(i));
-      let avgResult = new AggConfigResult(avg.agg, termResult, avg.at(i));
-      let maxResult = new AggConfigResult(max.agg, termResult, max.at(i));
+      const dateResult = new AggConfigResult(date.agg, void 0, date.at(i));
+      const termResult = new AggConfigResult(term.agg, dateResult, term.at(i));
+      const avgResult = new AggConfigResult(avg.agg, termResult, avg.at(i));
+      const maxResult = new AggConfigResult(max.agg, termResult, max.at(i));
       table.rows.push([dateResult, termResult, avgResult, maxResult]);
     });
 
-    let chartData = pointSeriesChartDataFromTable(vis, table);
+    const chartData = pointSeriesChartDataFromTable(vis, table);
     expect(chartData).to.be.an('object');
     expect(chartData.series).to.be.an('array');
     // one series for each extension, and then one for each metric inside
     expect(chartData.series).to.have.length(extensions.length * metricCount);
     chartData.series.forEach(function (siri, i) {
       // figure out the metric used to create this series
-      let metricAgg = siri.values[0].aggConfigResult.aggConfig;
-      let metric = avg.agg === metricAgg ? avg : max;
+      const metricAgg = siri.values[0].aggConfigResult.aggConfig;
+      const metric = avg.agg === metricAgg ? avg : max;
 
       expect(siri.values).to.have.length(rowsPerSegment);
       siri.values.forEach(function (point) {
diff --git a/src/ui/public/agg_response/point_series/__tests__/_ordered_date_axis.js b/src/ui/public/agg_response/point_series/__tests__/_ordered_date_axis.js
index db7763ca82772..1c3dc596f9fe5 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_ordered_date_axis.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_ordered_date_axis.js
@@ -6,7 +6,7 @@ import ngMock from 'ng_mock';
 import AggResponsePointSeriesOrderedDateAxisProvider from 'ui/agg_response/point_series/_ordered_date_axis';
 describe('orderedDateAxis', function () {
 
-  let baseArgs = {
+  const baseArgs = {
     vis: {
       indexPattern: {
         timeFieldName: '@timestamp'
@@ -37,7 +37,7 @@ describe('orderedDateAxis', function () {
 
   describe('xAxisFormatter', function () {
     it('sets the xAxisFormatter', function () {
-      let args = _.cloneDeep(baseArgs);
+      const args = _.cloneDeep(baseArgs);
       orderedDateAxis(args.vis, args.chart);
 
       expect(args.chart).to.have.property('xAxisFormatter');
@@ -45,10 +45,10 @@ describe('orderedDateAxis', function () {
     });
 
     it('formats values using moment, and returns strings', function () {
-      let args = _.cloneDeep(baseArgs);
+      const args = _.cloneDeep(baseArgs);
       orderedDateAxis(args.vis, args.chart);
 
-      let val = '2014-08-06T12:34:01';
+      const val = '2014-08-06T12:34:01';
       expect(args.chart.xAxisFormatter(val))
         .to.be(moment(val).format('hh:mm:ss'));
     });
@@ -56,7 +56,7 @@ describe('orderedDateAxis', function () {
 
   describe('ordered object', function () {
     it('sets date: true', function () {
-      let args = _.cloneDeep(baseArgs);
+      const args = _.cloneDeep(baseArgs);
       orderedDateAxis(args.vis, args.chart);
 
       expect(args.chart)
@@ -67,21 +67,21 @@ describe('orderedDateAxis', function () {
     });
 
     it('relies on agg.buckets for the interval', function () {
-      let args = _.cloneDeep(baseArgs);
-      let spy = sinon.spy(args.chart.aspects.x.agg.buckets, 'getInterval');
+      const args = _.cloneDeep(baseArgs);
+      const spy = sinon.spy(args.chart.aspects.x.agg.buckets, 'getInterval');
       orderedDateAxis(args.vis, args.chart);
       expect(spy).to.have.property('callCount', 1);
     });
 
     it('sets the min/max when the buckets are bounded', function () {
-      let args = _.cloneDeep(baseArgs);
+      const args = _.cloneDeep(baseArgs);
       orderedDateAxis(args.vis, args.chart);
       expect(moment.isMoment(args.chart.ordered.min)).to.be(true);
       expect(moment.isMoment(args.chart.ordered.max)).to.be(true);
     });
 
     it('does not set the min/max when the buckets are unbounded', function () {
-      let args = _.cloneDeep(baseArgs);
+      const args = _.cloneDeep(baseArgs);
       args.chart.aspects.x.agg.buckets.getBounds = _.constant();
       orderedDateAxis(args.vis, args.chart);
       expect(args.chart.ordered).to.not.have.property('min');
diff --git a/src/ui/public/agg_response/point_series/__tests__/_tooltip_formatter.js b/src/ui/public/agg_response/point_series/__tests__/_tooltip_formatter.js
index 73c9e796f252b..5a54de473e578 100644
--- a/src/ui/public/agg_response/point_series/__tests__/_tooltip_formatter.js
+++ b/src/ui/public/agg_response/point_series/__tests__/_tooltip_formatter.js
@@ -23,7 +23,7 @@ describe('tooltipFormatter', function () {
     return $row.eq(i).text().trim();
   }
 
-  let baseEvent = {
+  const baseEvent = {
     datum: {
       aggConfigResult: {
         aggConfig: agg('inner'),
@@ -42,20 +42,20 @@ describe('tooltipFormatter', function () {
   };
 
   it('returns html based on the mouse event', function () {
-    let event = _.cloneDeep(baseEvent);
-    let $el = $(tooltipFormatter(event));
-    let $rows = $el.find('tr');
+    const event = _.cloneDeep(baseEvent);
+    const $el = $(tooltipFormatter(event));
+    const $rows = $el.find('tr');
     expect($rows.size()).to.be(3);
 
-    let $row1 = $rows.eq(0).find('td');
+    const $row1 = $rows.eq(0).find('td');
     expect(cell($row1, 0)).to.be('inner');
     expect(cell($row1, 1)).to.be('(3)');
 
-    let $row2 = $rows.eq(1).find('td');
+    const $row2 = $rows.eq(1).find('td');
     expect(cell($row2, 0)).to.be('middle');
     expect(cell($row2, 1)).to.be('(2)');
 
-    let $row3 = $rows.eq(2).find('td');
+    const $row3 = $rows.eq(2).find('td');
     expect(cell($row3, 0)).to.be('top');
     expect(cell($row3, 1)).to.be('(1)');
   });
diff --git a/src/ui/public/agg_response/point_series/_fake_x_aspect.js b/src/ui/public/agg_response/point_series/_fake_x_aspect.js
index 5f9516a421cc2..aa4f2b6ca56ae 100644
--- a/src/ui/public/agg_response/point_series/_fake_x_aspect.js
+++ b/src/ui/public/agg_response/point_series/_fake_x_aspect.js
@@ -2,10 +2,10 @@ import VisAggConfigProvider from 'ui/vis/agg_config';
 import AggTypesAggTypeProvider from 'ui/agg_types/agg_type';
 
 export default function PointSeriesFakeXAxis(Private) {
-  let AggConfig = Private(VisAggConfigProvider);
-  let AggType = Private(AggTypesAggTypeProvider);
+  const AggConfig = Private(VisAggConfigProvider);
+  const AggType = Private(AggTypesAggTypeProvider);
 
-  let allAgg = new AggType({
+  const allAgg = new AggType({
     name: 'all',
     title: 'All docs',
     ordered: false,
@@ -13,7 +13,7 @@ export default function PointSeriesFakeXAxis(Private) {
   });
 
   return function makeFakeXAxis(vis) {
-    let fake = new AggConfig(vis, {
+    const fake = new AggConfig(vis, {
       type: allAgg,
       schema: vis.type.schemas.all.byName.segment
     });
diff --git a/src/ui/public/agg_response/point_series/_get_aspects.js b/src/ui/public/agg_response/point_series/_get_aspects.js
index f4978de298858..648a7f752b6ce 100644
--- a/src/ui/public/agg_response/point_series/_get_aspects.js
+++ b/src/ui/public/agg_response/point_series/_get_aspects.js
@@ -1,9 +1,9 @@
 import _ from 'lodash';
 import AggResponsePointSeriesFakeXAspectProvider from 'ui/agg_response/point_series/_fake_x_aspect';
 export default function PointSeriesGetAspects(Private) {
-  let fakeXAspect = Private(AggResponsePointSeriesFakeXAspectProvider);
+  const fakeXAspect = Private(AggResponsePointSeriesFakeXAspectProvider);
 
-  let map = {
+  const map = {
     segment: 'x',
     metric: 'y',
     radius: 'z',
@@ -12,12 +12,12 @@ export default function PointSeriesGetAspects(Private) {
   };
 
   function columnToAspect(aspects, col, i) {
-    let schema = col.aggConfig.schema.name;
+    const schema = col.aggConfig.schema.name;
 
-    let name = map[schema];
+    const name = map[schema];
     if (!name) throw new TypeError('unknown schema name "' + schema + '"');
 
-    let aspect = {
+    const aspect = {
       i: i,
       col: col,
       agg: col.aggConfig
@@ -36,7 +36,7 @@ export default function PointSeriesGetAspects(Private) {
    *                    may be undefined, a single aspect, or an array of aspects.
    */
   return function getAspects(vis, table) {
-    let aspects = _(table.columns)
+    const aspects = _(table.columns)
     // write each column into the aspects under it's group
     .transform(columnToAspect, {})
     // unwrap groups that only have one value, and validate groups that have more
diff --git a/src/ui/public/agg_response/point_series/_get_point.js b/src/ui/public/agg_response/point_series/_get_point.js
index 266ba41ce5c81..538a468ae2498 100644
--- a/src/ui/public/agg_response/point_series/_get_point.js
+++ b/src/ui/public/agg_response/point_series/_get_point.js
@@ -5,10 +5,10 @@ export default function PointSeriesGetPoint() {
   }
 
   return function getPoint(x, series, yScale, row, y, z) {
-    let zRow = z && row[z.i];
-    let xRow = row[x.i];
+    const zRow = z && row[z.i];
+    const xRow = row[x.i];
 
-    let point = {
+    const point = {
       x: unwrap(xRow, '_all'),
       xi: xRow && xRow.$order,
       y: unwrap(row[y.i]),
diff --git a/src/ui/public/agg_response/point_series/_get_series.js b/src/ui/public/agg_response/point_series/_get_series.js
index 817ec2712d96f..65e607d1ad7cc 100644
--- a/src/ui/public/agg_response/point_series/_get_series.js
+++ b/src/ui/public/agg_response/point_series/_get_series.js
@@ -2,30 +2,30 @@ import _ from 'lodash';
 import AggResponsePointSeriesGetPointProvider from 'ui/agg_response/point_series/_get_point';
 import AggResponsePointSeriesAddToSiriProvider from 'ui/agg_response/point_series/_add_to_siri';
 export default function PointSeriesGetSeries(Private) {
-  let getPoint = Private(AggResponsePointSeriesGetPointProvider);
-  let addToSiri = Private(AggResponsePointSeriesAddToSiriProvider);
+  const getPoint = Private(AggResponsePointSeriesGetPointProvider);
+  const addToSiri = Private(AggResponsePointSeriesAddToSiriProvider);
 
   return function getSeries(rows, chart) {
-    let aspects = chart.aspects;
-    let multiY = _.isArray(aspects.y);
-    let yScale = chart.yScale;
-    let partGetPoint = _.partial(getPoint, aspects.x, aspects.series, yScale);
+    const aspects = chart.aspects;
+    const multiY = _.isArray(aspects.y);
+    const yScale = chart.yScale;
+    const partGetPoint = _.partial(getPoint, aspects.x, aspects.series, yScale);
 
     let series = _(rows)
     .transform(function (series, row) {
       if (!multiY) {
-        let point = partGetPoint(row, aspects.y, aspects.z);
+        const point = partGetPoint(row, aspects.y, aspects.z);
         if (point) addToSiri(series, point, point.series);
         return;
       }
 
       aspects.y.forEach(function (y) {
-        let point = partGetPoint(row, y, aspects.z);
+        const point = partGetPoint(row, y, aspects.z);
         if (!point) return;
 
-        let prefix = point.series ? point.series + ': ' : '';
-        let seriesId = prefix + y.agg.id;
-        let seriesLabel = prefix + y.col.title;
+        const prefix = point.series ? point.series + ': ' : '';
+        const seriesId = prefix + y.agg.id;
+        const seriesLabel = prefix + y.col.title;
 
         addToSiri(series, point, seriesId, seriesLabel);
       });
@@ -36,11 +36,11 @@ export default function PointSeriesGetSeries(Private) {
 
     if (multiY) {
       series = _.sortBy(series, function (siri) {
-        let firstVal = siri.values[0];
+        const firstVal = siri.values[0];
         let y;
 
         if (firstVal) {
-          let agg = firstVal.aggConfigResult.aggConfig;
+          const agg = firstVal.aggConfigResult.aggConfig;
           y = _.find(aspects.y, function (y) {
             return y.agg === agg;
           });
diff --git a/src/ui/public/agg_response/point_series/_init_x_axis.js b/src/ui/public/agg_response/point_series/_init_x_axis.js
index 2a3584c3834f7..b4e271d33f08c 100644
--- a/src/ui/public/agg_response/point_series/_init_x_axis.js
+++ b/src/ui/public/agg_response/point_series/_init_x_axis.js
@@ -1,14 +1,14 @@
 define(function () {
   return function PointSeriesInitX() {
     return function initXAxis(chart) {
-      let x = chart.aspects.x;
+      const x = chart.aspects.x;
       chart.xAxisFormatter = x.agg ? x.agg.fieldFormatter() : String;
       chart.xAxisLabel = x.col.title;
 
       if (!x.agg || !x.agg.type.ordered) return;
 
       chart.ordered = {};
-      let xAggOutput = x.agg.write();
+      const xAggOutput = x.agg.write();
       if (xAggOutput.params.interval) {
         chart.ordered.interval = xAggOutput.params.interval;
       }
diff --git a/src/ui/public/agg_response/point_series/_init_y_axis.js b/src/ui/public/agg_response/point_series/_init_y_axis.js
index edd3060fc85c2..2f2d2039deb19 100644
--- a/src/ui/public/agg_response/point_series/_init_y_axis.js
+++ b/src/ui/public/agg_response/point_series/_init_y_axis.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 export default function PointSeriesInitYAxis() {
 
   return function initYAxis(chart) {
-    let y = chart.aspects.y;
-    let x = chart.aspects.x;
+    const y = chart.aspects.y;
+    const x = chart.aspects.x;
 
     if (_.isArray(y)) {
       // TODO: vis option should allow choosing this format
@@ -14,7 +14,7 @@ export default function PointSeriesInitYAxis() {
       chart.yAxisLabel = y.col.title;
     }
 
-    let xAggOutput = x.agg.write();
+    const xAggOutput = x.agg.write();
     chart.yScale = xAggOutput.metricScale || null;
   };
 };
diff --git a/src/ui/public/agg_response/point_series/_ordered_date_axis.js b/src/ui/public/agg_response/point_series/_ordered_date_axis.js
index 08b1d962252f2..1a72b4d6e6e3a 100644
--- a/src/ui/public/agg_response/point_series/_ordered_date_axis.js
+++ b/src/ui/public/agg_response/point_series/_ordered_date_axis.js
@@ -2,9 +2,9 @@ import moment from 'moment';
 export default function PointSeriesOrderedDateAxis(timefilter) {
 
   return function orderedDateAxis(vis, chart) {
-    let xAgg = chart.aspects.x.agg;
-    let buckets = xAgg.buckets;
-    let format = buckets.getScaledDateFormat();
+    const xAgg = chart.aspects.x.agg;
+    const buckets = xAgg.buckets;
+    const format = buckets.getScaledDateFormat();
 
     chart.xAxisFormatter = function (val) {
       return moment(val).format(format);
@@ -15,8 +15,8 @@ export default function PointSeriesOrderedDateAxis(timefilter) {
       interval: buckets.getInterval(),
     };
 
-    let axisOnTimeField = xAgg.fieldIsTimeField();
-    let bounds = buckets.getBounds();
+    const axisOnTimeField = xAgg.fieldIsTimeField();
+    const bounds = buckets.getBounds();
     if (bounds && axisOnTimeField) {
       chart.ordered.min = bounds.min;
       chart.ordered.max = bounds.max;
diff --git a/src/ui/public/agg_response/point_series/_tooltip_formatter.js b/src/ui/public/agg_response/point_series/_tooltip_formatter.js
index 715d692127d1e..c6e12fd7bf5b8 100644
--- a/src/ui/public/agg_response/point_series/_tooltip_formatter.js
+++ b/src/ui/public/agg_response/point_series/_tooltip_formatter.js
@@ -1,22 +1,22 @@
 import $ from 'jquery';
 export default function PointSeriesTooltipFormatter($compile, $rootScope) {
 
-  let $tooltipScope = $rootScope.$new();
-  let $tooltip = $(require('ui/agg_response/point_series/_tooltip.html'));
+  const $tooltipScope = $rootScope.$new();
+  const $tooltip = $(require('ui/agg_response/point_series/_tooltip.html'));
   $compile($tooltip)($tooltipScope);
 
   return function tooltipFormatter(event) {
-    let datum = event.datum;
+    const datum = event.datum;
     if (!datum || !datum.aggConfigResult) return '';
 
-    let details = $tooltipScope.details = [];
+    const details = $tooltipScope.details = [];
     let result = { $parent: datum.aggConfigResult };
 
     function addDetail(result) {
-      let agg = result.aggConfig;
-      let value = result.value;
+      const agg = result.aggConfig;
+      const value = result.value;
 
-      let detail = {
+      const detail = {
         value: agg.fieldFormatter()(value),
         label: agg.makeLabel()
       };
diff --git a/src/ui/public/agg_response/point_series/point_series.js b/src/ui/public/agg_response/point_series/point_series.js
index 0a2ccd90729c4..eb057200db47d 100644
--- a/src/ui/public/agg_response/point_series/point_series.js
+++ b/src/ui/public/agg_response/point_series/point_series.js
@@ -7,23 +7,23 @@ import AggResponsePointSeriesOrderedDateAxisProvider from 'ui/agg_response/point
 import AggResponsePointSeriesTooltipFormatterProvider from 'ui/agg_response/point_series/_tooltip_formatter';
 export default function PointSeriesProvider(Private) {
 
-  let getSeries = Private(AggResponsePointSeriesGetSeriesProvider);
-  let getAspects = Private(AggResponsePointSeriesGetAspectsProvider);
-  let initYAxis = Private(AggResponsePointSeriesInitYAxisProvider);
-  let initXAxis = Private(AggResponsePointSeriesInitXAxisProvider);
-  let setupOrderedDateXAxis = Private(AggResponsePointSeriesOrderedDateAxisProvider);
-  let tooltipFormatter = Private(AggResponsePointSeriesTooltipFormatterProvider);
+  const getSeries = Private(AggResponsePointSeriesGetSeriesProvider);
+  const getAspects = Private(AggResponsePointSeriesGetAspectsProvider);
+  const initYAxis = Private(AggResponsePointSeriesInitYAxisProvider);
+  const initXAxis = Private(AggResponsePointSeriesInitXAxisProvider);
+  const setupOrderedDateXAxis = Private(AggResponsePointSeriesOrderedDateAxisProvider);
+  const tooltipFormatter = Private(AggResponsePointSeriesTooltipFormatterProvider);
 
   return function pointSeriesChartDataFromTable(vis, table) {
-    let chart = {};
-    let aspects = chart.aspects = getAspects(vis, table);
+    const chart = {};
+    const aspects = chart.aspects = getAspects(vis, table);
 
     chart.tooltipFormatter = tooltipFormatter;
 
     initXAxis(chart);
     initYAxis(chart);
 
-    let datedX = aspects.x.agg.type.ordered && aspects.x.agg.type.ordered.date;
+    const datedX = aspects.x.agg.type.ordered && aspects.x.agg.type.ordered.date;
     if (datedX) {
       setupOrderedDateXAxis(vis, chart);
     }
diff --git a/src/ui/public/agg_response/tabify/__tests__/_buckets.js b/src/ui/public/agg_response/tabify/__tests__/_buckets.js
index e2ecc8e75d55d..ef34f4d3cafbd 100644
--- a/src/ui/public/agg_response/tabify/__tests__/_buckets.js
+++ b/src/ui/public/agg_response/tabify/__tests__/_buckets.js
@@ -12,13 +12,13 @@ describe('Buckets wrapper', function () {
 
   function test(aggResp, count, keys) {
     it('reads the length', function () {
-      let buckets = new Buckets(aggResp);
+      const buckets = new Buckets(aggResp);
       expect(buckets).to.have.length(count);
     });
 
     it('itterates properly, passing in the key', function () {
-      let buckets = new Buckets(aggResp);
-      let keysSent = [];
+      const buckets = new Buckets(aggResp);
+      const keysSent = [];
       buckets.forEach(function (bucket, key) {
         keysSent.push(key);
       });
@@ -29,7 +29,7 @@ describe('Buckets wrapper', function () {
   }
 
   describe('with object style buckets', function () {
-    let aggResp = {
+    const aggResp = {
       buckets: {
         '0-100': {},
         '100-200': {},
@@ -37,14 +37,14 @@ describe('Buckets wrapper', function () {
       }
     };
 
-    let count = 3;
-    let keys = ['0-100', '100-200', '200-300'];
+    const count = 3;
+    const keys = ['0-100', '100-200', '200-300'];
 
     test(aggResp, count, keys);
   });
 
   describe('with array style buckets', function () {
-    let aggResp = {
+    const aggResp = {
       buckets: [
         { key: '0-100', value: {} },
         { key: '100-200', value: {} },
@@ -52,8 +52,8 @@ describe('Buckets wrapper', function () {
       ]
     };
 
-    let count = 3;
-    let keys = ['0-100', '100-200', '200-300'];
+    const count = 3;
+    const keys = ['0-100', '100-200', '200-300'];
 
     test(aggResp, count, keys);
   });
diff --git a/src/ui/public/agg_response/tabify/__tests__/_get_columns.js b/src/ui/public/agg_response/tabify/__tests__/_get_columns.js
index d8db8717c2dc0..e0b315d757bb3 100644
--- a/src/ui/public/agg_response/tabify/__tests__/_get_columns.js
+++ b/src/ui/public/agg_response/tabify/__tests__/_get_columns.js
@@ -16,11 +16,11 @@ describe('get columns', function () {
   }));
 
   it('should inject a count metric if no aggs exist', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'pie'
     });
     while (vis.aggs.length) vis.aggs.pop();
-    let columns = getColumns(vis);
+    const columns = getColumns(vis);
 
     expect(columns).to.have.length(1);
     expect(columns[0]).to.have.property('aggConfig');
@@ -28,14 +28,14 @@ describe('get columns', function () {
   });
 
   it('should inject a count metric if only buckets exist', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'pie',
       aggs: [
         { type: 'date_histogram', schema: 'segment',  params: { field: '@timestamp' } }
       ]
     });
 
-    let columns = getColumns(vis);
+    const columns = getColumns(vis);
 
     expect(columns).to.have.length(2);
     expect(columns[1]).to.have.property('aggConfig');
@@ -43,7 +43,7 @@ describe('get columns', function () {
   });
 
   it('should inject the metric after each bucket if the vis is hierarchical', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'pie',
       aggs: [
         { type: 'date_histogram', schema: 'segment',  params: { field: '@timestamp' } },
@@ -53,7 +53,7 @@ describe('get columns', function () {
       ]
     });
 
-    let columns = getColumns(vis);
+    const columns = getColumns(vis);
 
     expect(columns).to.have.length(8);
     columns.forEach(function (column, i) {
@@ -63,7 +63,7 @@ describe('get columns', function () {
   });
 
   it('should inject the multiple metrics after each bucket if the vis is hierarchical', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'pie',
       aggs: [
         { type: 'date_histogram', schema: 'segment',  params: { field: '@timestamp' } },
@@ -75,7 +75,7 @@ describe('get columns', function () {
       ]
     });
 
-    let columns = getColumns(vis);
+    const columns = getColumns(vis);
 
     function checkColumns(column, i) {
       expect(column).to.have.property('aggConfig');
@@ -94,13 +94,13 @@ describe('get columns', function () {
 
     expect(columns).to.have.length(12);
     for (let i = 0; i < columns.length; i += 3) {
-      let counts = { buckets: 0, metrics: 0 };
+      const counts = { buckets: 0, metrics: 0 };
       columns.slice(i, i + 3).forEach(checkColumns);
     }
   });
 
   it('should put all metrics at the end of the columns if the vis is not hierarchical', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         { type: 'date_histogram', schema: 'segment',  params: { field: '@timestamp' } },
@@ -112,7 +112,7 @@ describe('get columns', function () {
       ]
     });
 
-    let columns = getColumns(vis);
+    const columns = getColumns(vis);
     expect(columns).to.have.length(6);
 
     // sum should be last
diff --git a/src/ui/public/agg_response/tabify/__tests__/_integration.js b/src/ui/public/agg_response/tabify/__tests__/_integration.js
index ea5d6096219d6..528a732f29d09 100644
--- a/src/ui/public/agg_response/tabify/__tests__/_integration.js
+++ b/src/ui/public/agg_response/tabify/__tests__/_integration.js
@@ -26,13 +26,13 @@ describe('tabifyAggResponse Integration', function () {
   }
 
   it('transforms a simple response properly', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: []
     });
     normalizeIds(vis);
 
-    let resp = tabifyAggResponse(vis, fixtures.metricOnly, { canSplit: false });
+    const resp = tabifyAggResponse(vis, fixtures.metricOnly, { canSplit: false });
 
     expect(resp).to.not.have.property('tables');
     expect(resp).to.have.property('rows').and.property('columns');
@@ -81,7 +81,7 @@ describe('tabifyAggResponse Integration', function () {
     function expectRootGroup(rootTableGroup, expectInnerTables) {
       expect(rootTableGroup).to.have.property('tables');
 
-      let tables = rootTableGroup.tables;
+      const tables = rootTableGroup.tables;
       expect(tables).to.be.an('array').and.have.length(3);
       expectExtensionSplit(tables[0], 'png', expectInnerTables);
       expectExtensionSplit(tables[1], 'css', expectInnerTables);
@@ -155,7 +155,7 @@ describe('tabifyAggResponse Integration', function () {
       // only complete rows, and only put the metrics at the end.
 
       vis.isHierarchical = _.constant(false);
-      let tabbed = tabifyAggResponse(vis, esResp);
+      const tabbed = tabifyAggResponse(vis, esResp);
 
       expectRootGroup(tabbed, function expectTable(table, splitKey) {
         expectColumns(table, [src, os, avg]);
@@ -181,7 +181,7 @@ describe('tabifyAggResponse Integration', function () {
       // the existing bucket and it's metric
 
       vis.isHierarchical = _.constant(true);
-      let tabbed = tabifyAggResponse(vis, esResp, {
+      const tabbed = tabifyAggResponse(vis, esResp, {
         partialRows: true
       });
 
@@ -215,7 +215,7 @@ describe('tabifyAggResponse Integration', function () {
       // the end
 
       vis.isHierarchical = _.constant(true);
-      let tabbed = tabifyAggResponse(vis, esResp, {
+      const tabbed = tabifyAggResponse(vis, esResp, {
         partialRows: true,
         minimalColumns: true
       });
@@ -247,7 +247,7 @@ describe('tabifyAggResponse Integration', function () {
       // create metric columns after each bucket
 
       vis.isHierarchical = _.constant(false);
-      let tabbed = tabifyAggResponse(vis, esResp, {
+      const tabbed = tabifyAggResponse(vis, esResp, {
         minimalColumns: false
       });
 
diff --git a/src/ui/public/agg_response/tabify/__tests__/_response_writer.js b/src/ui/public/agg_response/tabify/__tests__/_response_writer.js
index 5f81ef8190d68..48275dbbf7679 100644
--- a/src/ui/public/agg_response/tabify/__tests__/_response_writer.js
+++ b/src/ui/public/agg_response/tabify/__tests__/_response_writer.js
@@ -42,15 +42,15 @@ describe('ResponseWriter class', function () {
     defineSetup(true);
 
     it('gets the columns for the vis', function () {
-      let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-      let writer = new ResponseWriter(vis);
+      const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+      const writer = new ResponseWriter(vis);
 
       expect(getColumns).to.have.property('callCount', 1);
       expect(getColumns.firstCall.args[0]).to.be(vis);
     });
 
     it('collects the aggConfigs from each column in aggStack', function () {
-      let aggs = [
+      const aggs = [
         { type: 'date_histogram', schema: 'segment', params: { field: '@timestamp' } },
         { type: 'terms', schema: 'segment', params: { field: 'extension' } },
         { type: 'avg', schema: 'metric', params: { field: '@timestamp' } }
@@ -60,12 +60,12 @@ describe('ResponseWriter class', function () {
         return { aggConfig: agg };
       }));
 
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: aggs
       });
 
-      let writer = new ResponseWriter(vis);
+      const writer = new ResponseWriter(vis);
       expect(writer.aggStack).to.be.an('array');
       expect(writer.aggStack).to.have.length(aggs.length);
       writer.aggStack.forEach(function (agg, i) {
@@ -74,40 +74,40 @@ describe('ResponseWriter class', function () {
     });
 
     it('sets canSplit=true by default', function () {
-      let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-      let writer = new ResponseWriter(vis);
+      const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+      const writer = new ResponseWriter(vis);
       expect(writer).to.have.property('canSplit', true);
     });
 
     it('sets canSplit=false when config says to', function () {
-      let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-      let writer = new ResponseWriter(vis, { canSplit: false });
+      const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+      const writer = new ResponseWriter(vis, { canSplit: false });
       expect(writer).to.have.property('canSplit', false);
     });
 
     describe('sets partialRows', function () {
       it('to the value of the config if set', function () {
-        let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-        let partial = Boolean(Math.round(Math.random()));
+        const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+        const partial = Boolean(Math.round(Math.random()));
 
-        let writer = new ResponseWriter(vis, { partialRows: partial });
+        const writer = new ResponseWriter(vis, { partialRows: partial });
         expect(writer).to.have.property('partialRows', partial);
       });
 
       it('to the value of vis.isHierarchical if no config', function () {
-        let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-        let hierarchical = Boolean(Math.round(Math.random()));
+        const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+        const hierarchical = Boolean(Math.round(Math.random()));
         sinon.stub(vis, 'isHierarchical').returns(hierarchical);
 
-        let writer = new ResponseWriter(vis, {});
+        const writer = new ResponseWriter(vis, {});
         expect(writer).to.have.property('partialRows', hierarchical);
       });
     });
 
     it('starts off with a root TableGroup', function () {
-      let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+      const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
 
-      let writer = new ResponseWriter(vis);
+      const writer = new ResponseWriter(vis);
       expect(writer.root).to.be.a(TableGroup);
       expect(writer.splitStack).to.be.an('array');
       expect(writer.splitStack).to.have.length(1);
@@ -120,29 +120,29 @@ describe('ResponseWriter class', function () {
 
     describe('#response()', function () {
       it('returns the root TableGroup if splitting', function () {
-        let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-        let writer = new ResponseWriter(vis);
+        const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+        const writer = new ResponseWriter(vis);
         expect(writer.response()).to.be(writer.root);
       });
 
       it('returns the first table if not splitting', function () {
-        let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-        let writer = new ResponseWriter(vis, { canSplit: false });
-        let table = writer._table();
+        const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+        const writer = new ResponseWriter(vis, { canSplit: false });
+        const table = writer._table();
         expect(writer.response()).to.be(table);
       });
 
       it('adds columns to all of the tables', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', params: { field: '_type' }, schema: 'split' },
             { type: 'count', schema: 'metric' }
           ]
         });
-        let buckets = new Buckets({ buckets: [ { key: 'nginx' }, { key: 'apache' } ] });
-        let writer = new ResponseWriter(vis);
-        let tables = [];
+        const buckets = new Buckets({ buckets: [ { key: 'nginx' }, { key: 'apache' } ] });
+        const writer = new ResponseWriter(vis);
+        const tables = [];
 
         writer.split(vis.aggs[0], buckets, function () {
           writer.cell(vis.aggs[1], 100, function () {
@@ -154,11 +154,11 @@ describe('ResponseWriter class', function () {
           expect(table.columns == null).to.be(true);
         });
 
-        let resp = writer.response();
+        const resp = writer.response();
         expect(resp).to.be.a(TableGroup);
         expect(resp.tables).to.have.length(2);
 
-        let nginx = resp.tables.shift();
+        const nginx = resp.tables.shift();
         expect(nginx).to.have.property('aggConfig', vis.aggs[0]);
         expect(nginx).to.have.property('key', 'nginx');
         expect(nginx.tables).to.have.length(1);
@@ -166,7 +166,7 @@ describe('ResponseWriter class', function () {
           expect(_.contains(tables, table)).to.be(true);
         });
 
-        let apache = resp.tables.shift();
+        const apache = resp.tables.shift();
         expect(apache).to.have.property('aggConfig', vis.aggs[0]);
         expect(apache).to.have.property('key', 'apache');
         expect(apache.tables).to.have.length(1);
@@ -184,16 +184,16 @@ describe('ResponseWriter class', function () {
 
     describe('#split()', function () {
       it('with break if the user has specified that splitting is to be disabled', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', schema: 'split', params: { field: '_type' } },
             { type: 'count', schema: 'metric' }
           ]
         });
-        let agg = vis.aggs.bySchemaName.split[0];
-        let buckets = new Buckets({ buckets: [ { key: 'apache' } ]});
-        let writer = new ResponseWriter(vis, { canSplit: false });
+        const agg = vis.aggs.bySchemaName.split[0];
+        const buckets = new Buckets({ buckets: [ { key: 'apache' } ]});
+        const writer = new ResponseWriter(vis, { canSplit: false });
 
         expect(function () {
           writer.split(agg, buckets, _.noop);
@@ -201,7 +201,7 @@ describe('ResponseWriter class', function () {
       });
 
       it('forks the acrStack and rewrites the parents', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', params: { field: 'extension' }, schema: 'segment' },
@@ -211,10 +211,10 @@ describe('ResponseWriter class', function () {
           ]
         });
 
-        let writer = new ResponseWriter(vis, { asAggConfigResults: true });
-        let extensions = new Buckets({ buckets: [ { key: 'jpg' }, { key: 'png' } ] });
-        let types = new Buckets({ buckets: [ { key: 'nginx' }, { key: 'apache' } ] });
-        let os = new Buckets({ buckets: [ { key: 'window' }, { key: 'osx' } ] });
+        const writer = new ResponseWriter(vis, { asAggConfigResults: true });
+        const extensions = new Buckets({ buckets: [ { key: 'jpg' }, { key: 'png' } ] });
+        const types = new Buckets({ buckets: [ { key: 'nginx' }, { key: 'apache' } ] });
+        const os = new Buckets({ buckets: [ { key: 'window' }, { key: 'osx' } ] });
 
         extensions.forEach(function (b, extension) {
           writer.cell(vis.aggs[0], extension, function () {
@@ -230,11 +230,11 @@ describe('ResponseWriter class', function () {
           });
         });
 
-        let tables = _.flattenDeep(_.pluck(writer.response().tables, 'tables'));
+        const tables = _.flattenDeep(_.pluck(writer.response().tables, 'tables'));
         expect(tables.length).to.be(types.length);
 
         // collect the far left acr from each table
-        let leftAcrs = _.pluck(tables, 'rows[0][0]');
+        const leftAcrs = _.pluck(tables, 'rows[0][0]');
 
         leftAcrs.forEach(function (acr, i, acrs) {
           expect(acr.aggConfig).to.be(vis.aggs[0]);
@@ -243,7 +243,7 @@ describe('ResponseWriter class', function () {
 
           // for all but the last acr, compare to the next
           if (i + 1 >= acrs.length) return;
-          let acr2 = leftAcrs[i + 1];
+          const acr2 = leftAcrs[i + 1];
 
           expect(acr.key).to.be(acr2.key);
           expect(acr.value).to.be(acr2.value);
@@ -258,8 +258,8 @@ describe('ResponseWriter class', function () {
     describe('#cell()', function () {
       it('logs a cell in the ResponseWriters row buffer, calls the block arg, then removes the value from the buffer',
       function () {
-        let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-        let writer = new ResponseWriter(vis);
+        const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+        const writer = new ResponseWriter(vis);
 
         expect(writer.rowBuffer).to.have.length(0);
         writer.cell({}, 500, function () {
@@ -272,10 +272,10 @@ describe('ResponseWriter class', function () {
 
     describe('#row()', function () {
       it('writes the ResponseWriters internal rowBuffer into a table', function () {
-        let vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
-        let writer = new ResponseWriter(vis);
+        const vis = new Vis(indexPattern, { type: 'histogram', aggs: [] });
+        const writer = new ResponseWriter(vis);
 
-        let table = writer._table();
+        const table = writer._table();
         writer.cell({}, 1, function () {
           writer.cell({}, 2, function () {
             writer.cell({}, 3, function () {
@@ -289,7 +289,7 @@ describe('ResponseWriter class', function () {
       });
 
       it('always writes to the table group at the top of the split stack', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', schema: 'split', params: { field: '_type' } },
@@ -298,20 +298,20 @@ describe('ResponseWriter class', function () {
             { type: 'count', schema: 'metric' }
           ]
         });
-        let splits = vis.aggs.bySchemaName.split;
+        const splits = vis.aggs.bySchemaName.split;
 
-        let type = splits[0];
-        let typeBuckets = new Buckets({ buckets: [ { key: 'nginx' }, { key: 'apache' } ] });
+        const type = splits[0];
+        const typeBuckets = new Buckets({ buckets: [ { key: 'nginx' }, { key: 'apache' } ] });
 
-        let ext = splits[1];
-        let extBuckets = new Buckets({ buckets: [ { key: 'jpg' }, { key: 'png' } ] });
+        const ext = splits[1];
+        const extBuckets = new Buckets({ buckets: [ { key: 'jpg' }, { key: 'png' } ] });
 
-        let os = splits[2];
-        let osBuckets = new Buckets({ buckets: [ { key: 'windows' }, { key: 'mac' } ] });
+        const os = splits[2];
+        const osBuckets = new Buckets({ buckets: [ { key: 'windows' }, { key: 'mac' } ] });
 
-        let count = vis.aggs[3];
+        const count = vis.aggs[3];
 
-        let writer = new ResponseWriter(vis);
+        const writer = new ResponseWriter(vis);
         writer.split(type, typeBuckets, function () {
           writer.split(ext, extBuckets, function () {
             writer.split(os, osBuckets, function (bucket, key) {
@@ -322,7 +322,7 @@ describe('ResponseWriter class', function () {
           });
         });
 
-        let resp = writer.response();
+        const resp = writer.response();
         let sum = 0;
         let tables = 0;
         (function recurse(t) {
@@ -347,7 +347,7 @@ describe('ResponseWriter class', function () {
       });
 
       it('writes partial rows for hierarchical vis', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'pie',
           aggs: [
             { type: 'terms', schema: 'segment', params: { field: '_type' }},
@@ -355,8 +355,8 @@ describe('ResponseWriter class', function () {
           ]
         });
 
-        let writer = new ResponseWriter(vis);
-        let table = writer._table();
+        const writer = new ResponseWriter(vis);
+        const table = writer._table();
         writer.cell(vis.aggs[0], 'apache', function () {
           writer.row();
         });
@@ -366,7 +366,7 @@ describe('ResponseWriter class', function () {
       });
 
       it('skips partial rows for non-hierarchical vis', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', schema: 'segment', params: { field: '_type' }},
@@ -374,8 +374,8 @@ describe('ResponseWriter class', function () {
           ]
         });
 
-        let writer = new ResponseWriter(vis);
-        let table = writer._table();
+        const writer = new ResponseWriter(vis);
+        const table = writer._table();
         writer.cell(vis.aggs[0], 'apache', function () {
           writer.row();
         });
diff --git a/src/ui/public/agg_response/tabify/__tests__/_table.js b/src/ui/public/agg_response/tabify/__tests__/_table.js
index 1e4a869bcc229..ef54028aa5df6 100644
--- a/src/ui/public/agg_response/tabify/__tests__/_table.js
+++ b/src/ui/public/agg_response/tabify/__tests__/_table.js
@@ -12,16 +12,16 @@ describe('Table class', function () {
   }));
 
   it('exposes rows array, but not the columns', function () {
-    let table = new Table();
+    const table = new Table();
     expect(table.rows).to.be.an('array');
     expect(table.columns == null).to.be.ok();
   });
 
   describe('#aggConfig', function () {
     it('accepts a column from the table and returns its agg config', function () {
-      let table = new Table();
-      let football = {};
-      let column = {
+      const table = new Table();
+      const football = {};
+      const column = {
         aggConfig: football
       };
 
@@ -30,7 +30,7 @@ describe('Table class', function () {
 
     it('throws a TypeError if the column is malformed', function () {
       expect(function () {
-        let notAColumn = {};
+        const notAColumn = {};
         (new Table()).aggConfig(notAColumn);
       }).to.throwException(TypeError);
     });
@@ -38,12 +38,12 @@ describe('Table class', function () {
 
   describe('#title', function () {
     it('returns nothing if the table is not part of a table group', function () {
-      let table = new Table();
+      const table = new Table();
       expect(table.title()).to.be('');
     });
 
     it('returns the title of the TableGroup if the table is part of one', function () {
-      let table = new Table();
+      const table = new Table();
       table.$parent = {
         title: 'TableGroup Title',
         tables: [table]
@@ -55,9 +55,9 @@ describe('Table class', function () {
 
   describe('#field', function () {
     it('calls the columns aggConfig#field() method', function () {
-      let table = new Table();
-      let football = {};
-      let column = {
+      const table = new Table();
+      const football = {};
+      const column = {
         aggConfig: {
           field: _.constant(football)
         }
@@ -69,9 +69,9 @@ describe('Table class', function () {
 
   describe('#fieldFormatter', function () {
     it('calls the columns aggConfig#fieldFormatter() method', function () {
-      let table = new Table();
-      let football = {};
-      let column = {
+      const table = new Table();
+      const football = {};
+      const column = {
         aggConfig: {
           fieldFormatter: _.constant(football)
         }
diff --git a/src/ui/public/agg_response/tabify/__tests__/_table_group.js b/src/ui/public/agg_response/tabify/__tests__/_table_group.js
index 5455caa143f34..d880596d45852 100644
--- a/src/ui/public/agg_response/tabify/__tests__/_table_group.js
+++ b/src/ui/public/agg_response/tabify/__tests__/_table_group.js
@@ -10,7 +10,7 @@ describe('Table Group class', function () {
   }));
 
   it('exposes tables array and empty aggConfig, key and title', function () {
-    let tableGroup = new TableGroup();
+    const tableGroup = new TableGroup();
     expect(tableGroup.tables).to.be.an('array');
     expect(tableGroup.aggConfig).to.be(null);
     expect(tableGroup.key).to.be(null);
diff --git a/src/ui/public/agg_response/tabify/_buckets.js b/src/ui/public/agg_response/tabify/_buckets.js
index 7d05c83a882b1..001147c460675 100644
--- a/src/ui/public/agg_response/tabify/_buckets.js
+++ b/src/ui/public/agg_response/tabify/_buckets.js
@@ -15,7 +15,7 @@ export default function AggResponseBucketsProvider() {
   }
 
   Buckets.prototype.forEach = function (fn) {
-    let buckets = this.buckets;
+    const buckets = this.buckets;
 
     if (this.objectMode) {
       this._keys.forEach(function (key) {
diff --git a/src/ui/public/agg_response/tabify/_get_columns.js b/src/ui/public/agg_response/tabify/_get_columns.js
index b9268891cadc3..a4f2e9041ebd9 100644
--- a/src/ui/public/agg_response/tabify/_get_columns.js
+++ b/src/ui/public/agg_response/tabify/_get_columns.js
@@ -1,10 +1,10 @@
 import _ from 'lodash';
 import VisAggConfigProvider from 'ui/vis/agg_config';
 export default function GetColumnsProvider(Private) {
-  let AggConfig = Private(VisAggConfigProvider);
+  const AggConfig = Private(VisAggConfigProvider);
 
   return function getColumns(vis, minimal) {
-    let aggs = vis.aggs.getResponseAggs();
+    const aggs = vis.aggs.getResponseAggs();
 
     if (minimal == null) minimal = !vis.isHierarchical();
 
@@ -23,10 +23,10 @@ export default function GetColumnsProvider(Private) {
     }
 
     // supposed to be bucket,...metrics,bucket,...metrics
-    let columns = [];
+    const columns = [];
 
     // seperate the metrics
-    let grouped = _.groupBy(aggs, function (agg) {
+    const grouped = _.groupBy(aggs, function (agg) {
       return agg.schema.group;
     });
 
diff --git a/src/ui/public/agg_response/tabify/_response_writer.js b/src/ui/public/agg_response/tabify/_response_writer.js
index 53f1ee01782ac..d023392815a7f 100644
--- a/src/ui/public/agg_response/tabify/_response_writer.js
+++ b/src/ui/public/agg_response/tabify/_response_writer.js
@@ -4,9 +4,9 @@ import AggResponseTabifyTableProvider from 'ui/agg_response/tabify/_table';
 import AggResponseTabifyTableGroupProvider from 'ui/agg_response/tabify/_table_group';
 import AggResponseTabifyGetColumnsProvider from 'ui/agg_response/tabify/_get_columns';
 export default function TabbedAggResponseWriterProvider(Private) {
-  let Table = Private(AggResponseTabifyTableProvider);
-  let TableGroup = Private(AggResponseTabifyTableGroupProvider);
-  let getColumns = Private(AggResponseTabifyGetColumnsProvider);
+  const Table = Private(AggResponseTabifyTableProvider);
+  const TableGroup = Private(AggResponseTabifyTableGroupProvider);
+  const getColumns = Private(AggResponseTabifyGetColumnsProvider);
 
 
   _.class(SplitAcr).inherits(AggConfigResult);
@@ -25,7 +25,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
     this.opts = opts || {};
     this.rowBuffer = [];
 
-    let visIsHier = vis.isHierarchical();
+    const visIsHier = vis.isHierarchical();
 
     // do the options allow for splitting? we will only split if true and
     // tabify calls the split method.
@@ -67,9 +67,9 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {Table/TableGroup} table - the created table
    */
   TabbedAggResponseWriter.prototype._table = function (group, agg, key) {
-    let Class = (group) ? TableGroup : Table;
-    let table = new Class();
-    let parent = this.splitStack[0];
+    const Class = (group) ? TableGroup : Table;
+    const table = new Class();
+    const parent = this.splitStack[0];
 
     if (group) {
       table.aggConfig = agg;
@@ -95,7 +95,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @param  {function} block - a function to execute for each sub bucket
    */
   TabbedAggResponseWriter.prototype.split = function (agg, buckets, block) {
-    let self = this;
+    const self = this;
 
     if (!self.canSplit) {
       throw new Error('attempted to split when splitting is disabled');
@@ -127,7 +127,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
   };
 
   TabbedAggResponseWriter.prototype._removeAggFromColumns = function (agg) {
-    let i = _.findIndex(this.columns, function (col) {
+    const i = _.findIndex(this.columns, function (col) {
       return col.aggConfig === agg;
     });
 
@@ -140,8 +140,8 @@ export default function TabbedAggResponseWriterProvider(Private) {
 
     // hierarchical vis creats additional columns for each bucket
     // we will remove those too
-    let mCol = this.columns.splice(i, 1).pop();
-    let mI = _.findIndex(this.aggStack, function (agg) {
+    const mCol = this.columns.splice(i, 1).pop();
+    const mI = _.findIndex(this.aggStack, function (agg) {
       return agg === mCol.aggConfig;
     });
 
@@ -160,8 +160,8 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {SplitAcr} - the AggConfigResult created for the split bucket
    */
   TabbedAggResponseWriter.prototype._injectParentSplit = function (agg, key) {
-    let oldList = this.acrStack;
-    let newList = this.acrStack = [];
+    const oldList = this.acrStack;
+    const newList = this.acrStack = [];
 
     // walk from right to left through the old stack
     // and move things to the new stack
@@ -175,7 +175,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
 
     // walk from right to left, emptying the previous list
     while (oldList.length) {
-      let acr = oldList.pop();
+      const acr = oldList.pop();
 
       // ignore other splits
       if (acr instanceof SplitAcr) {
@@ -189,11 +189,11 @@ export default function TabbedAggResponseWriterProvider(Private) {
         newList.unshift(injected);
       }
 
-      let newAcr = new AggConfigResult(acr.aggConfig, newList[0], acr.value, acr.aggConfig.getKey(acr));
+      const newAcr = new AggConfigResult(acr.aggConfig, newList[0], acr.value, acr.aggConfig.getKey(acr));
       newList.unshift(newAcr);
 
       // and replace the acr in the row buffer if its there
-      let rowI = this.rowBuffer.indexOf(acr);
+      const rowI = this.rowBuffer.indexOf(acr);
       if (rowI > -1) {
         this.rowBuffer[rowI] = newAcr;
       }
@@ -215,7 +215,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
       value = new AggConfigResult(agg, this.acrStack[0], value, value);
     }
 
-    let staskResult = this.asAggConfigResults && value.type === 'bucket';
+    const staskResult = this.asAggConfigResults && value.type === 'bucket';
 
     this.rowBuffer.push(value);
     if (staskResult) this.acrStack.unshift(value);
@@ -237,14 +237,14 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {undefined}
    */
   TabbedAggResponseWriter.prototype.row = function (buffer) {
-    let cells = buffer || this.rowBuffer.slice(0);
+    const cells = buffer || this.rowBuffer.slice(0);
 
     if (!this.partialRows && cells.length < this.columns.length) {
       return;
     }
 
-    let split = this.splitStack[0];
-    let table = split.tables[0] || this._table(false);
+    const split = this.splitStack[0];
+    const table = split.tables[0] || this._table(false);
 
     while (cells.length < this.columns.length) cells.push('');
     table.rows.push(cells);
@@ -257,7 +257,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
    * @return {object} - the final table-tree
    */
   TabbedAggResponseWriter.prototype.response = function () {
-    let columns = this.columns;
+    const columns = this.columns;
 
     // give the columns some metadata
     columns.map(function (col) {
@@ -272,7 +272,7 @@ export default function TabbedAggResponseWriterProvider(Private) {
 
     if (this.canSplit) return this.root;
 
-    let table = this.root.tables[0];
+    const table = this.root.tables[0];
     if (!table) return;
 
     delete table.$parent;
diff --git a/src/ui/public/agg_response/tabify/tabify.js b/src/ui/public/agg_response/tabify/tabify.js
index 722a1a12b8032..36296bf2f7377 100644
--- a/src/ui/public/agg_response/tabify/tabify.js
+++ b/src/ui/public/agg_response/tabify/tabify.js
@@ -4,15 +4,15 @@ import AggResponseTabifyResponseWriterProvider from 'ui/agg_response/tabify/_res
 import AggResponseTabifyBucketsProvider from 'ui/agg_response/tabify/_buckets';
 export default function tabifyAggResponseProvider(Private, Notifier) {
 
-  let AggConfig = Private(VisAggConfigProvider);
-  let TabbedAggResponseWriter = Private(AggResponseTabifyResponseWriterProvider);
-  let Buckets = Private(AggResponseTabifyBucketsProvider);
-  let notify = new Notifier({ location: 'agg_response/tabify'});
+  const AggConfig = Private(VisAggConfigProvider);
+  const TabbedAggResponseWriter = Private(AggResponseTabifyResponseWriterProvider);
+  const Buckets = Private(AggResponseTabifyBucketsProvider);
+  const notify = new Notifier({ location: 'agg_response/tabify'});
 
   function tabifyAggResponse(vis, esResponse, respOpts) {
-    let write = new TabbedAggResponseWriter(vis, respOpts);
+    const write = new TabbedAggResponseWriter(vis, respOpts);
 
-    let topLevelBucket = _.assign({}, esResponse.aggregations, {
+    const topLevelBucket = _.assign({}, esResponse.aggregations, {
       doc_count: esResponse.hits.total
     });
 
@@ -31,13 +31,13 @@ export default function tabifyAggResponseProvider(Private, Notifier) {
    * @returns {undefined}
    */
   function collectBucket(write, bucket, key) {
-    let agg = write.aggStack.shift();
+    const agg = write.aggStack.shift();
 
     switch (agg.schema.group) {
       case 'buckets':
-        let buckets = new Buckets(bucket[agg.id]);
+        const buckets = new Buckets(bucket[agg.id]);
         if (buckets.length) {
-          let splitting = write.canSplit && agg.schema.name === 'split';
+          const splitting = write.canSplit && agg.schema.name === 'split';
           if (splitting) {
             write.split(agg, buckets, function forEachBucket(subBucket, key) {
               collectBucket(write, subBucket, agg.getKey(subBucket), key);
@@ -63,7 +63,7 @@ export default function tabifyAggResponseProvider(Private, Notifier) {
         }
         break;
       case 'metrics':
-        let value = agg.getValue(bucket);
+        const value = agg.getValue(bucket);
         write.cell(agg, value, function () {
           if (!write.aggStack.length) {
             // row complete
@@ -82,7 +82,7 @@ export default function tabifyAggResponseProvider(Private, Notifier) {
   // write empty values for each bucket agg, then write
   // the metrics from the initial bucket using collectBucket()
   function passEmptyBuckets(write, bucket, key) {
-    let agg = write.aggStack.shift();
+    const agg = write.aggStack.shift();
 
     switch (agg.schema.group) {
       case 'metrics':
diff --git a/src/ui/public/agg_table/__tests__/_group.js b/src/ui/public/agg_table/__tests__/_group.js
index 88c7cb92092ed..31bdc70eb5aa5 100644
--- a/src/ui/public/agg_table/__tests__/_group.js
+++ b/src/ui/public/agg_table/__tests__/_group.js
@@ -34,13 +34,13 @@ describe('AggTableGroup Directive', function () {
 
 
   it('renders a simple split response properly', function () {
-    let vis = new Vis(indexPattern, 'table');
+    const vis = new Vis(indexPattern, 'table');
     $scope.group = tabifyAggResponse(vis, fixtures.metricOnly);
     $scope.sort = {
       columnIndex: null,
       direction: null
     };
-    let $el = $('<kbn-agg-table-group group="group"></kbn-agg-table-group>');
+    const $el = $('<kbn-agg-table-group group="group"></kbn-agg-table-group>');
 
     $compile($el)($scope);
     $scope.$digest();
@@ -50,7 +50,7 @@ describe('AggTableGroup Directive', function () {
   });
 
   it('renders nothing if the table list is empty', function () {
-    let $el = $('<kbn-agg-table-group group="group"></kbn-agg-table-group>');
+    const $el = $('<kbn-agg-table-group group="group"></kbn-agg-table-group>');
 
     $scope.group = {
       tables: []
@@ -59,12 +59,12 @@ describe('AggTableGroup Directive', function () {
     $compile($el)($scope);
     $scope.$digest();
 
-    let $subTables = $el.find('kbn-agg-table');
+    const $subTables = $el.find('kbn-agg-table');
     expect($subTables.size()).to.be(0);
   });
 
   it('renders a complex response properly', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'pie',
       aggs: [
         { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
@@ -77,15 +77,15 @@ describe('AggTableGroup Directive', function () {
       agg.id = 'agg_' + (i + 1);
     });
 
-    let group = $scope.group = tabifyAggResponse(vis, fixtures.threeTermBuckets);
-    let $el = $('<kbn-agg-table-group group="group"></kbn-agg-table-group>');
+    const group = $scope.group = tabifyAggResponse(vis, fixtures.threeTermBuckets);
+    const $el = $('<kbn-agg-table-group group="group"></kbn-agg-table-group>');
     $compile($el)($scope);
     $scope.$digest();
 
-    let $subTables = $el.find('kbn-agg-table');
+    const $subTables = $el.find('kbn-agg-table');
     expect($subTables.size()).to.be(3);
 
-    let $subTableHeaders = $el.find('.agg-table-group-header');
+    const $subTableHeaders = $el.find('.agg-table-group-header');
     expect($subTableHeaders.size()).to.be(3);
 
     $subTableHeaders.each(function (i) {
diff --git a/src/ui/public/agg_table/__tests__/_table.js b/src/ui/public/agg_table/__tests__/_table.js
index 062bd6ccfb37f..b6b1f5cf75821 100644
--- a/src/ui/public/agg_table/__tests__/_table.js
+++ b/src/ui/public/agg_table/__tests__/_table.js
@@ -35,10 +35,10 @@ describe('AggTable Directive', function () {
 
 
   it('renders a simple response properly', function () {
-    let vis = new Vis(indexPattern, 'table');
+    const vis = new Vis(indexPattern, 'table');
     $scope.table = tabifyAggResponse(vis, fixtures.metricOnly, { canSplit: false });
 
-    let $el = $compile('<kbn-agg-table table="table"></kbn-agg-table>')($scope);
+    const $el = $compile('<kbn-agg-table table="table"></kbn-agg-table>')($scope);
     $scope.$digest();
 
     expect($el.find('tbody').size()).to.be(1);
@@ -48,14 +48,14 @@ describe('AggTable Directive', function () {
 
   it('renders nothing if the table is empty', function () {
     $scope.table = null;
-    let $el = $compile('<kbn-agg-table table="table"></kbn-agg-table>')($scope);
+    const $el = $compile('<kbn-agg-table table="table"></kbn-agg-table>')($scope);
     $scope.$digest();
 
     expect($el.find('tbody').size()).to.be(0);
   });
 
   it('renders a complex response properly', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'pie',
       aggs: [
         { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
@@ -69,27 +69,27 @@ describe('AggTable Directive', function () {
     });
 
     $scope.table = tabifyAggResponse(vis, fixtures.threeTermBuckets, { canSplit: false });
-    let $el = $('<kbn-agg-table table="table"></kbn-agg-table>');
+    const $el = $('<kbn-agg-table table="table"></kbn-agg-table>');
     $compile($el)($scope);
     $scope.$digest();
 
     expect($el.find('tbody').size()).to.be(1);
 
-    let $rows = $el.find('tbody tr');
+    const $rows = $el.find('tbody tr');
     expect($rows.size()).to.be.greaterThan(0);
 
     function validBytes(str) {
       expect(str).to.match(/^\d+$/);
-      let bytesAsNum = _.parseInt(str);
+      const bytesAsNum = _.parseInt(str);
       expect(bytesAsNum === 0 || bytesAsNum > 1000).to.be.ok();
     }
 
     $rows.each(function (i) {
       // 6 cells in every row
-      let $cells = $(this).find('td');
+      const $cells = $(this).find('td');
       expect($cells.size()).to.be(6);
 
-      let txts = $cells.map(function () {
+      const txts = $cells.map(function () {
         return $(this).text().trim();
       });
 
@@ -109,11 +109,11 @@ describe('AggTable Directive', function () {
 
   describe('aggTable.toCsv()', function () {
     it('escapes and formats the rows and columns properly', function () {
-      let $el = $compile('<kbn-agg-table table="table">')($scope);
+      const $el = $compile('<kbn-agg-table table="table">')($scope);
       $scope.$digest();
 
-      let $tableScope = $el.isolateScope();
-      let aggTable = $tableScope.aggTable;
+      const $tableScope = $el.isolateScope();
+      const aggTable = $tableScope.aggTable;
 
       $tableScope.table = {
         columns: [
@@ -150,13 +150,13 @@ describe('AggTable Directive', function () {
     });
 
     it('calls _saveAs properly', function () {
-      let $el = $compile('<kbn-agg-table table="table">')($scope);
+      const $el = $compile('<kbn-agg-table table="table">')($scope);
       $scope.$digest();
 
-      let $tableScope = $el.isolateScope();
-      let aggTable = $tableScope.aggTable;
+      const $tableScope = $el.isolateScope();
+      const aggTable = $tableScope.aggTable;
 
-      let saveAs = sinon.stub(aggTable, '_saveAs');
+      const saveAs = sinon.stub(aggTable, '_saveAs');
       $tableScope.table = {
         columns: [
           { title: 'one' },
@@ -172,7 +172,7 @@ describe('AggTable Directive', function () {
       aggTable.exportAsCsv();
 
       expect(saveAs.callCount).to.be(1);
-      let call = saveAs.getCall(0);
+      const call = saveAs.getCall(0);
       expect(call.args[0]).to.be.a(FakeBlob);
       expect(call.args[0].slices).to.eql([
         'one,two,"with double-quotes("")"' + '\r\n' +
@@ -185,12 +185,12 @@ describe('AggTable Directive', function () {
     });
 
     it('should use the export-title attribute', function () {
-      let expected = 'export file name';
-      let $el = $compile(`<kbn-agg-table table="table" export-title="exportTitle">`)($scope);
+      const expected = 'export file name';
+      const $el = $compile(`<kbn-agg-table table="table" export-title="exportTitle">`)($scope);
       $scope.$digest();
 
-      let $tableScope = $el.isolateScope();
-      let aggTable = $tableScope.aggTable;
+      const $tableScope = $el.isolateScope();
+      const aggTable = $tableScope.aggTable;
       $tableScope.table = {
         columns: [],
         rows: []
diff --git a/src/ui/public/agg_table/agg_table.js b/src/ui/public/agg_table/agg_table.js
index a6853254ef8ec..5b05afa7f929b 100644
--- a/src/ui/public/agg_table/agg_table.js
+++ b/src/ui/public/agg_table/agg_table.js
@@ -27,7 +27,7 @@ uiModules
       return compileRecursiveDirective.compile($el);
     },
     controller: function ($scope) {
-      let self = this;
+      const self = this;
 
       self._saveAs = require('@spalger/filesaver').saveAs;
       self.csv = {
@@ -36,15 +36,15 @@ uiModules
       };
 
       self.exportAsCsv = function (formatted) {
-        let csv = new Blob([self.toCsv(formatted)], { type: 'text/plain' });
+        const csv = new Blob([self.toCsv(formatted)], { type: 'text/plain' });
         self._saveAs(csv, self.csv.filename);
       };
 
       self.toCsv = function (formatted) {
-        let rows = $scope.table.rows;
-        let columns = formatted ? $scope.formattedColumns : $scope.table.columns;
-        let nonAlphaNumRE = /[^a-zA-Z0-9]/;
-        let allDoubleQuoteRE = /"/g;
+        const rows = $scope.table.rows;
+        const columns = formatted ? $scope.formattedColumns : $scope.table.columns;
+        const nonAlphaNumRE = /[^a-zA-Z0-9]/;
+        const allDoubleQuoteRE = /"/g;
 
         function escape(val) {
           if (!formatted && _.isObject(val)) val = val.valueOf();
@@ -56,7 +56,7 @@ uiModules
         }
 
         // escape each cell in each row
-        let csvRows = rows.map(function (row) {
+        const csvRows = rows.map(function (row) {
           return row.map(escape);
         });
 
@@ -71,7 +71,7 @@ uiModules
       };
 
       $scope.$watch('table', function () {
-        let table = $scope.table;
+        const table = $scope.table;
 
         if (!table) {
           $scope.rows = null;
@@ -82,14 +82,14 @@ uiModules
         self.csv.filename = ($scope.exportTitle || table.title() || 'table') + '.csv';
         $scope.rows = table.rows;
         $scope.formattedColumns = table.columns.map(function (col, i) {
-          let agg = $scope.table.aggConfig(col);
-          let field = agg.field();
-          let formattedColumn = {
+          const agg = $scope.table.aggConfig(col);
+          const field = agg.field();
+          const formattedColumn = {
             title: col.title,
             filterable: field && field.filterable && agg.schema.group === 'buckets'
           };
 
-          let last = i === (table.columns.length - 1);
+          const last = i === (table.columns.length - 1);
 
           if (last || (agg.schema.group === 'metrics')) {
             formattedColumn.class = 'visualize-table-right';
diff --git a/src/ui/public/agg_table/agg_table_group.js b/src/ui/public/agg_table/agg_table_group.js
index 2cd1031182ba4..cff0e1180f951 100644
--- a/src/ui/public/agg_table/agg_table_group.js
+++ b/src/ui/public/agg_table/agg_table_group.js
@@ -28,10 +28,10 @@ uiModules
 
             if (!group || !group.tables.length) return;
 
-            let firstTable = group.tables[0];
-            let params = firstTable.aggConfig && firstTable.aggConfig.params;
+            const firstTable = group.tables[0];
+            const params = firstTable.aggConfig && firstTable.aggConfig.params;
             // render groups that have Table children as if they were rows, because iteration is cleaner
-            let childLayout = (params && !params.row) ? 'columns' : 'rows';
+            const childLayout = (params && !params.row) ? 'columns' : 'rows';
 
             $scope[childLayout] = group.tables;
           });
diff --git a/src/ui/public/agg_types/__tests__/agg_param_writer.js b/src/ui/public/agg_types/__tests__/agg_param_writer.js
index 58d113f2e6c5c..0de3f8b1eb5b5 100644
--- a/src/ui/public/agg_types/__tests__/agg_param_writer.js
+++ b/src/ui/public/agg_types/__tests__/agg_param_writer.js
@@ -4,10 +4,10 @@ import AggTypesIndexProvider from 'ui/agg_types/index';
 import RegistryVisTypesProvider from 'ui/registry/vis_types';
 import FixturesStubbedLogstashIndexPatternProvider from 'fixtures/stubbed_logstash_index_pattern';
 module.exports = function AggParamWriterHelper(Private) {
-  let Vis = Private(VisProvider);
-  let aggTypes = Private(AggTypesIndexProvider);
-  let visTypes = Private(RegistryVisTypesProvider);
-  let stubbedLogstashIndexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
+  const Vis = Private(VisProvider);
+  const aggTypes = Private(AggTypesIndexProvider);
+  const visTypes = Private(RegistryVisTypesProvider);
+  const stubbedLogstashIndexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
 
   /**
    * Helper object for writing aggParams. Specify an aggType and it will find a vis & schema, and
@@ -29,7 +29,7 @@ module.exports = function AggParamWriterHelper(Private) {
    * @param {string} opts.aggType - the name of the aggType we want to test. ('histogram', 'filter', etc.)
    */
   function AggParamWriter(opts) {
-    let self = this;
+    const self = this;
 
     self.aggType = opts.aggType;
     if (_.isString(self.aggType)) {
@@ -47,7 +47,7 @@ module.exports = function AggParamWriterHelper(Private) {
 
     // find a suitable vis type and schema
     _.find(visTypes, function (visType) {
-      let schema = _.find(visType.schemas.all, function (schema) {
+      const schema = _.find(visType.schemas.all, function (schema) {
         // type, type, type, type, type... :(
         return schema.group === self.aggType.type;
       });
@@ -69,7 +69,7 @@ module.exports = function AggParamWriterHelper(Private) {
   }
 
   AggParamWriter.prototype.write = function (paramValues) {
-    let self = this;
+    const self = this;
     paramValues = _.clone(paramValues);
 
     if (self.aggType.params.byName.field && !paramValues.field) {
@@ -90,7 +90,7 @@ module.exports = function AggParamWriterHelper(Private) {
       }]
     });
 
-    let aggConfig = _.find(self.vis.aggs, function (aggConfig) {
+    const aggConfig = _.find(self.vis.aggs, function (aggConfig) {
       return aggConfig.type === self.aggType;
     });
 
diff --git a/src/ui/public/agg_types/__tests__/agg_params.js b/src/ui/public/agg_types/__tests__/agg_params.js
index 1eff825ecb769..84d06c6b6471e 100644
--- a/src/ui/public/agg_types/__tests__/agg_params.js
+++ b/src/ui/public/agg_types/__tests__/agg_params.js
@@ -28,11 +28,11 @@ describe('AggParams class', function () {
 
   describe('constructor args', function () {
     it('accepts an array of param defs', function () {
-      let params = [
+      const params = [
         { name: 'one' },
         { name: 'two' }
       ];
-      let aggParams = new AggParams(params);
+      const aggParams = new AggParams(params);
 
       expect(aggParams).to.have.length(params.length);
       expect(aggParams).to.be.an(Array);
@@ -42,43 +42,43 @@ describe('AggParams class', function () {
 
   describe('AggParam creation', function () {
     it('Uses the FieldAggParam class for params with the name "field"', function () {
-      let params = [
+      const params = [
         { name: 'field' }
       ];
-      let aggParams = new AggParams(params);
+      const aggParams = new AggParams(params);
 
       expect(aggParams).to.have.length(params.length);
       expect(aggParams[0]).to.be.a(FieldAggParam);
     });
 
     it('Uses the OptionedAggParam class for params of type "optioned"', function () {
-      let params = [
+      const params = [
         {
           name: 'interval',
           type: 'optioned'
         }
       ];
-      let aggParams = new AggParams(params);
+      const aggParams = new AggParams(params);
 
       expect(aggParams).to.have.length(params.length);
       expect(aggParams[0]).to.be.a(OptionedAggParam);
     });
 
     it('Uses the RegexAggParam class for params of type "regex"', function () {
-      let params = [
+      const params = [
         {
           name: 'exclude',
           type: 'regex'
         }
       ];
-      let aggParams = new AggParams(params);
+      const aggParams = new AggParams(params);
 
       expect(aggParams).to.have.length(params.length);
       expect(aggParams[0]).to.be.a(RegexAggParam);
     });
 
     it('Always converts the params to a BaseAggParam', function () {
-      let params = [
+      const params = [
         {
           name: 'height',
           editor: '<blink>high</blink>'
@@ -92,7 +92,7 @@ describe('AggParams class', function () {
           editor: '<blink>small</blink>'
         }
       ];
-      let aggParams = new AggParams(params);
+      const aggParams = new AggParams(params);
 
       expect(BaseAggParam).to.have.property('callCount', params.length);
       expect(FieldAggParam).to.have.property('callCount', 0);
diff --git a/src/ui/public/agg_types/__tests__/agg_type.js b/src/ui/public/agg_types/__tests__/agg_type.js
index 94dbcab47d495..f8bb6616fe9aa 100644
--- a/src/ui/public/agg_types/__tests__/agg_type.js
+++ b/src/ui/public/agg_types/__tests__/agg_type.js
@@ -39,7 +39,7 @@ describe('AggType Class', function () {
     });
 
     describe('application of config properties', function () {
-      let copiedConfigProps = [
+      const copiedConfigProps = [
         'name',
         'title',
         'makeLabel',
@@ -48,11 +48,11 @@ describe('AggType Class', function () {
 
       describe('"' + copiedConfigProps.join('", "') + '"', function () {
         it('assigns the config value to itself', function () {
-          let config = _.transform(copiedConfigProps, function (config, prop) {
+          const config = _.transform(copiedConfigProps, function (config, prop) {
             config[prop] = {};
           }, {});
 
-          let aggType = new AggType(config);
+          const aggType = new AggType(config);
 
           copiedConfigProps.forEach(function (prop) {
             expect(aggType[prop]).to.be(config[prop]);
@@ -62,7 +62,7 @@ describe('AggType Class', function () {
 
       describe('makeLabel', function () {
         it('makes a function when the makeLabel config is not specified', function () {
-          let someGetter = function () {};
+          const someGetter = function () {};
 
           let aggType = new AggType({
             makeLabel: someGetter
@@ -81,7 +81,7 @@ describe('AggType Class', function () {
 
       describe('getFormat', function () {
         it('returns the formatter for the aggConfig', function () {
-          let aggType = new AggType({});
+          const aggType = new AggType({});
 
           let vis = new Vis(indexPattern, {
             type: 'histogram',
@@ -112,9 +112,9 @@ describe('AggType Class', function () {
         });
 
         it('can be overridden via config', function () {
-          let someGetter = function () {};
+          const someGetter = function () {};
 
-          let aggType = new AggType({
+          const aggType = new AggType({
             getFormat: someGetter
           });
 
@@ -128,7 +128,7 @@ describe('AggType Class', function () {
         });
 
         it('defaults to AggParams object with JSON param', function () {
-          let aggType = new AggType({
+          const aggType = new AggType({
             name: 'smart agg'
           });
 
@@ -139,7 +139,7 @@ describe('AggType Class', function () {
         });
 
         it('can disable customLabel', function () {
-          let aggType = new AggType({
+          const aggType = new AggType({
             name: 'smart agg',
             customLabels: false
           });
@@ -149,13 +149,13 @@ describe('AggType Class', function () {
         });
 
         it('passes the params arg directly to the AggParams constructor', function () {
-          let params = [
+          const params = [
             {name: 'one'},
             {name: 'two'}
           ];
-          let paramLength = params.length + 2; // json and custom label are always appended
+          const paramLength = params.length + 2; // json and custom label are always appended
 
-          let aggType = new AggType({
+          const aggType = new AggType({
             name: 'bucketeer',
             params: params
           });
@@ -169,8 +169,8 @@ describe('AggType Class', function () {
 
       describe('getResponseAggs', function () {
         it('copies the value', function () {
-          let football = {};
-          let aggType = new AggType({
+          const football = {};
+          const aggType = new AggType({
             getResponseAggs: football
           });
 
@@ -178,7 +178,7 @@ describe('AggType Class', function () {
         });
 
         it('defaults to _.noop', function () {
-          let aggType = new AggType({});
+          const aggType = new AggType({});
 
           expect(aggType.getResponseAggs).to.be(_.noop);
         });
diff --git a/src/ui/public/agg_types/__tests__/bucket_count_between.js b/src/ui/public/agg_types/__tests__/bucket_count_between.js
index 75c2a4e46fdf7..61f0828f4b14f 100644
--- a/src/ui/public/agg_types/__tests__/bucket_count_between.js
+++ b/src/ui/public/agg_types/__tests__/bucket_count_between.js
@@ -32,7 +32,7 @@ describe('bucketCountBetween util', function () {
   }));
 
   it('returns a positive number when a is before b', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         {
@@ -46,14 +46,14 @@ describe('bucketCountBetween util', function () {
       ]
     });
 
-    let a = vis.aggs.byTypeName.date_histogram[0];
-    let b = vis.aggs.byTypeName.terms[0];
-    let count = bucketCountBetween(a, b);
+    const a = vis.aggs.byTypeName.date_histogram[0];
+    const b = vis.aggs.byTypeName.terms[0];
+    const count = bucketCountBetween(a, b);
     expect(isNegative(count)).to.be(false);
   });
 
   it('returns a negative number when a is after b', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         {
@@ -67,14 +67,14 @@ describe('bucketCountBetween util', function () {
       ]
     });
 
-    let a = vis.aggs.byTypeName.terms[0];
-    let b = vis.aggs.byTypeName.date_histogram[0];
-    let count = bucketCountBetween(a, b);
+    const a = vis.aggs.byTypeName.terms[0];
+    const b = vis.aggs.byTypeName.date_histogram[0];
+    const count = bucketCountBetween(a, b);
     expect(isNegative(count)).to.be(true);
   });
 
   it('returns 0 when there are no buckets between a and b', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         {
@@ -88,13 +88,13 @@ describe('bucketCountBetween util', function () {
       ]
     });
 
-    let a = vis.aggs.byTypeName.date_histogram[0];
-    let b = vis.aggs.byTypeName.terms[0];
+    const a = vis.aggs.byTypeName.date_histogram[0];
+    const b = vis.aggs.byTypeName.terms[0];
     expect(bucketCountBetween(a, b)).to.be(0);
   });
 
   it('returns null when b is not in the aggs', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         {
@@ -104,8 +104,8 @@ describe('bucketCountBetween util', function () {
       ]
     });
 
-    let a = vis.aggs.byTypeName.date_histogram[0];
-    let b = new AggConfig(vis, {
+    const a = vis.aggs.byTypeName.date_histogram[0];
+    const b = new AggConfig(vis, {
       type: 'terms',
       schema: 'segment'
     });
@@ -114,7 +114,7 @@ describe('bucketCountBetween util', function () {
   });
 
   it('returns null when a is not in the aggs', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: [
         {
@@ -124,27 +124,27 @@ describe('bucketCountBetween util', function () {
       ]
     });
 
-    let a = new AggConfig(vis, {
+    const a = new AggConfig(vis, {
       type: 'terms',
       schema: 'segment'
     });
-    let b = vis.aggs.byTypeName.date_histogram[0];
+    const b = vis.aggs.byTypeName.date_histogram[0];
 
     expect(bucketCountBetween(a, b)).to.be(null);
   });
 
   it('returns null when a and b are not in the aggs', function () {
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       type: 'histogram',
       aggs: []
     });
 
-    let a = new AggConfig(vis, {
+    const a = new AggConfig(vis, {
       type: 'terms',
       schema: 'segment'
     });
 
-    let b = new AggConfig(vis, {
+    const b = new AggConfig(vis, {
       type: 'date_histogram',
       schema: 'segment'
     });
@@ -154,14 +154,14 @@ describe('bucketCountBetween util', function () {
 
   function countTest(pre, post) {
     return function () {
-      let schemas = visTypes.byName.histogram.schemas.buckets;
+      const schemas = visTypes.byName.histogram.schemas.buckets;
 
       // slow for this test is actually somewhere around 1/2 a sec
       this.slow(500);
 
       function randBucketAggForVis(vis) {
-        let schema = _.sample(schemas);
-        let aggType = _.sample(aggTypes.byType.buckets);
+        const schema = _.sample(schemas);
+        const aggType = _.sample(aggTypes.byType.buckets);
 
         return new AggConfig(vis, {
           schema: schema,
@@ -170,18 +170,18 @@ describe('bucketCountBetween util', function () {
       }
 
       _.times(50, function (n) {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: []
         });
 
-        let randBucketAgg = _.partial(randBucketAggForVis, vis);
+        const randBucketAgg = _.partial(randBucketAggForVis, vis);
 
-        let a = randBucketAgg();
-        let b = randBucketAgg();
+        const a = randBucketAgg();
+        const b = randBucketAgg();
 
         // create n aggs between a and b
-        let aggs = [];
+        const aggs = [];
         aggs.fill = function (n) {
           for (let i = 0; i < n; i++) {
             aggs.push(randBucketAgg());
diff --git a/src/ui/public/agg_types/__tests__/buckets/_geo_hash.js b/src/ui/public/agg_types/__tests__/buckets/_geo_hash.js
index c4b2650cd6219..e0511b95f948c 100644
--- a/src/ui/public/agg_types/__tests__/buckets/_geo_hash.js
+++ b/src/ui/public/agg_types/__tests__/buckets/_geo_hash.js
@@ -6,7 +6,7 @@ describe('Geohash Agg', function () {
 
   describe('write', function () {
 
-    let paramWriter = new AggTypesBucketsGeoHashProvider(function PrivateMock() {
+    const paramWriter = new AggTypesBucketsGeoHashProvider(function PrivateMock() {
       return function BucketMock(geohashProvider) {
         return geohashProvider.params[4];
       };
diff --git a/src/ui/public/agg_types/__tests__/buckets/_histogram.js b/src/ui/public/agg_types/__tests__/buckets/_histogram.js
index 325e91ecf56c9..ea66ce28e7a94 100644
--- a/src/ui/public/agg_types/__tests__/buckets/_histogram.js
+++ b/src/ui/public/agg_types/__tests__/buckets/_histogram.js
@@ -28,7 +28,7 @@ describe('Histogram Agg', function () {
 
     beforeEach(ngMock.module('kibana'));
     beforeEach(ngMock.inject(function (Private) {
-      let AggParamWriter = Private(AggParamWriterProvider);
+      const AggParamWriter = Private(AggParamWriterProvider);
       paramWriter = new AggParamWriter({ aggType: 'histogram' });
     }));
 
@@ -36,18 +36,18 @@ describe('Histogram Agg', function () {
       // reads aggConfig.params.interval, writes to dsl.interval
 
       it('accepts a number', function () {
-        let output = paramWriter.write({ interval: 100 });
+        const output = paramWriter.write({ interval: 100 });
         expect(output.params).to.have.property('interval', 100);
       });
 
       it('accepts a string', function () {
-        let output = paramWriter.write({ interval: '10' });
+        const output = paramWriter.write({ interval: '10' });
         expect(output.params).to.have.property('interval', 10);
       });
 
       it('fails on non-numeric values', function () {
         // template validation prevents this from users, not devs
-        let output = paramWriter.write({ interval: [] });
+        const output = paramWriter.write({ interval: [] });
         expect(isNaN(output.params.interval)).to.be.ok();
       });
     });
@@ -81,7 +81,7 @@ describe('Histogram Agg', function () {
 
     describe('extended_bounds', function () {
       it('writes when only eb.min is set', function () {
-        let output = paramWriter.write({
+        const output = paramWriter.write({
           min_doc_count: true,
           extended_bounds: { min: 0 }
         });
@@ -90,7 +90,7 @@ describe('Histogram Agg', function () {
       });
 
       it('writes when only eb.max is set', function () {
-        let output = paramWriter.write({
+        const output = paramWriter.write({
           min_doc_count: true,
           extended_bounds: { max: 0 }
         });
@@ -99,7 +99,7 @@ describe('Histogram Agg', function () {
       });
 
       it('writes when both eb.min and eb.max are set', function () {
-        let output = paramWriter.write({
+        const output = paramWriter.write({
           min_doc_count: true,
           extended_bounds: { min: 99, max: 100 }
         });
@@ -108,7 +108,7 @@ describe('Histogram Agg', function () {
       });
 
       it('does not write when nothing is set', function () {
-        let output = paramWriter.write({
+        const output = paramWriter.write({
           min_doc_count: true,
           extended_bounds: {}
         });
@@ -116,7 +116,7 @@ describe('Histogram Agg', function () {
       });
 
       it('does not write when min_doc_count is false', function () {
-        let output = paramWriter.write({
+        const output = paramWriter.write({
           min_doc_count: false,
           extended_bounds: { min: 99, max: 100 }
         });
diff --git a/src/ui/public/agg_types/__tests__/buckets/_range.js b/src/ui/public/agg_types/__tests__/buckets/_range.js
index a25c447bdd38f..a9a5744250651 100644
--- a/src/ui/public/agg_types/__tests__/buckets/_range.js
+++ b/src/ui/public/agg_types/__tests__/buckets/_range.js
@@ -9,7 +9,7 @@ import FixturesStubbedLogstashIndexPatternProvider from 'fixtures/stubbed_logsta
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 describe('Range Agg', function () {
 
-  let buckets = values(resp.aggregations[1].buckets);
+  const buckets = values(resp.aggregations[1].buckets);
 
   let range;
   let Vis;
@@ -21,7 +21,7 @@ describe('Range Agg', function () {
     Vis = Private(VisProvider);
     indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
 
-    let BytesFormat = Private(RegistryFieldFormatsProvider).byId.bytes;
+    const BytesFormat = Private(RegistryFieldFormatsProvider).byId.bytes;
 
     indexPattern.fieldFormatMap.bytes = new BytesFormat({
       pattern: '0,0.[000] b'
@@ -32,7 +32,7 @@ describe('Range Agg', function () {
 
   describe('formating', function () {
     it('formats bucket keys properly', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -49,8 +49,8 @@ describe('Range Agg', function () {
         ]
       });
 
-      let agg = vis.aggs.byTypeName.range[0];
-      let format = function (val) {
+      const agg = vis.aggs.byTypeName.range[0];
+      const format = function (val) {
         return agg.fieldFormatter()(agg.getKey(val));
       };
       expect(format(buckets[0])).to.be('-∞ to 1 KB');
diff --git a/src/ui/public/agg_types/__tests__/buckets/create_filter/date_histogram.js b/src/ui/public/agg_types/__tests__/buckets/create_filter/date_histogram.js
index 9efc4515038aa..1f092220bbedf 100644
--- a/src/ui/public/agg_types/__tests__/buckets/create_filter/date_histogram.js
+++ b/src/ui/public/agg_types/__tests__/buckets/create_filter/date_histogram.js
@@ -25,10 +25,10 @@ describe('AggConfig Filters', function () {
 
     beforeEach(ngMock.module('kibana'));
     beforeEach(ngMock.inject(function (Private, $injector) {
-      let Vis = Private(VisProvider);
-      let indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
-      let createFilter = Private(AggTypesBucketsCreateFilterDateHistogramProvider);
-      let TimeBuckets = Private(TimeBucketsProvider);
+      const Vis = Private(VisProvider);
+      const indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
+      const createFilter = Private(AggTypesBucketsCreateFilterDateHistogramProvider);
+      const TimeBuckets = Private(TimeBucketsProvider);
       intervalOptions = Private(AggTypesBucketsIntervalOptionsProvider);
 
       init = function (interval, duration) {
@@ -51,7 +51,7 @@ describe('AggConfig Filters', function () {
         bucketKey = _.sample(aggResp.aggregations['1'].buckets).key;
         bucketStart = moment(bucketKey);
 
-        let timePad = moment.duration(duration / 2);
+        const timePad = moment.duration(duration / 2);
         agg.buckets.setBounds({
           min: bucketStart.clone().subtract(timePad),
           max: bucketStart.clone().add(timePad),
@@ -68,7 +68,7 @@ describe('AggConfig Filters', function () {
       expect(filter).to.have.property('range');
       expect(filter.range).to.have.property(field.name);
 
-      let fieldParams = filter.range[field.name];
+      const fieldParams = filter.range[field.name];
       expect(fieldParams).to.have.property('gte');
       expect(fieldParams.gte).to.be.a('number');
 
@@ -98,8 +98,8 @@ describe('AggConfig Filters', function () {
 
         init(option.val, duration);
 
-        let interval = agg.buckets.getInterval();
-        let params = filter.range[field.name];
+        const interval = agg.buckets.getInterval();
+        const params = filter.range[field.name];
 
         expect(params.gte).to.be(+bucketStart);
         expect(params.lt).to.be(+bucketStart.clone().add(interval));
diff --git a/src/ui/public/agg_types/__tests__/buckets/create_filter/date_range.js b/src/ui/public/agg_types/__tests__/buckets/create_filter/date_range.js
index 117852228b6cc..5beaf4ba72409 100644
--- a/src/ui/public/agg_types/__tests__/buckets/create_filter/date_range.js
+++ b/src/ui/public/agg_types/__tests__/buckets/create_filter/date_range.js
@@ -23,7 +23,7 @@ describe('AggConfig Filters', function () {
     }));
 
     it('should return a range filter for date_range agg', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -38,8 +38,8 @@ describe('AggConfig Filters', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.date_range[0];
-      let filter = createFilter(aggConfig, 'February 1st, 2015 to February 7th, 2015');
+      const aggConfig = vis.aggs.byTypeName.date_range[0];
+      const filter = createFilter(aggConfig, 'February 1st, 2015 to February 7th, 2015');
       expect(filter).to.have.property('range');
       expect(filter).to.have.property('meta');
       expect(filter.meta).to.have.property('index', indexPattern.id);
diff --git a/src/ui/public/agg_types/__tests__/buckets/create_filter/filters.js b/src/ui/public/agg_types/__tests__/buckets/create_filter/filters.js
index 43069575965af..53c5e524f66b8 100644
--- a/src/ui/public/agg_types/__tests__/buckets/create_filter/filters.js
+++ b/src/ui/public/agg_types/__tests__/buckets/create_filter/filters.js
@@ -23,7 +23,7 @@ describe('AggConfig Filters', function () {
     }));
 
     it('should return a filters filter', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -39,8 +39,8 @@ describe('AggConfig Filters', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.filters[0];
-      let filter = createFilter(aggConfig, '_type:nginx');
+      const aggConfig = vis.aggs.byTypeName.filters[0];
+      const filter = createFilter(aggConfig, '_type:nginx');
       expect(_.omit(filter, 'meta')).to.eql(aggConfig.params.filters[1].input);
       expect(filter.meta).to.have.property('index', indexPattern.id);
 
diff --git a/src/ui/public/agg_types/__tests__/buckets/create_filter/histogram.js b/src/ui/public/agg_types/__tests__/buckets/create_filter/histogram.js
index 702cd0ea746b7..69af6d4a7cd48 100644
--- a/src/ui/public/agg_types/__tests__/buckets/create_filter/histogram.js
+++ b/src/ui/public/agg_types/__tests__/buckets/create_filter/histogram.js
@@ -23,7 +23,7 @@ describe('AggConfig Filters', function () {
     }));
 
     it('should return an range filter for histogram', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -34,8 +34,8 @@ describe('AggConfig Filters', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.histogram[0];
-      let filter = createFilter(aggConfig, 2048);
+      const aggConfig = vis.aggs.byTypeName.histogram[0];
+      const filter = createFilter(aggConfig, 2048);
       expect(filter).to.have.property('meta');
       expect(filter.meta).to.have.property('index', indexPattern.id);
       expect(filter).to.have.property('range');
diff --git a/src/ui/public/agg_types/__tests__/buckets/create_filter/ip_range.js b/src/ui/public/agg_types/__tests__/buckets/create_filter/ip_range.js
index d98e8f0727efc..8f028e9c20591 100644
--- a/src/ui/public/agg_types/__tests__/buckets/create_filter/ip_range.js
+++ b/src/ui/public/agg_types/__tests__/buckets/create_filter/ip_range.js
@@ -21,7 +21,7 @@ describe('AggConfig Filters', function () {
     }));
 
     it('should return a range filter for ip_range agg', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -40,8 +40,8 @@ describe('AggConfig Filters', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.ip_range[0];
-      let filter = createFilter(aggConfig, '0.0.0.0-1.1.1.1');
+      const aggConfig = vis.aggs.byTypeName.ip_range[0];
+      const filter = createFilter(aggConfig, '0.0.0.0-1.1.1.1');
       expect(filter).to.have.property('range');
       expect(filter).to.have.property('meta');
       expect(filter.meta).to.have.property('index', indexPattern.id);
@@ -51,7 +51,7 @@ describe('AggConfig Filters', function () {
     });
 
     it('should return a range filter for ip_range agg using a CIDR mask', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -70,8 +70,8 @@ describe('AggConfig Filters', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.ip_range[0];
-      let filter = createFilter(aggConfig, '67.129.65.201/27');
+      const aggConfig = vis.aggs.byTypeName.ip_range[0];
+      const filter = createFilter(aggConfig, '67.129.65.201/27');
       expect(filter).to.have.property('range');
       expect(filter).to.have.property('meta');
       expect(filter.meta).to.have.property('index', indexPattern.id);
diff --git a/src/ui/public/agg_types/__tests__/buckets/create_filter/range.js b/src/ui/public/agg_types/__tests__/buckets/create_filter/range.js
index b6ccd71d38cd5..023141bba6382 100644
--- a/src/ui/public/agg_types/__tests__/buckets/create_filter/range.js
+++ b/src/ui/public/agg_types/__tests__/buckets/create_filter/range.js
@@ -21,7 +21,7 @@ describe('AggConfig Filters', function () {
     }));
 
     it('should return a range filter for range agg', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -37,8 +37,8 @@ describe('AggConfig Filters', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.range[0];
-      let filter = createFilter(aggConfig, { gte: 1024, lt: 2048.0 });
+      const aggConfig = vis.aggs.byTypeName.range[0];
+      const filter = createFilter(aggConfig, { gte: 1024, lt: 2048.0 });
       expect(filter).to.have.property('range');
       expect(filter).to.have.property('meta');
       expect(filter.meta).to.have.property('index', indexPattern.id);
diff --git a/src/ui/public/agg_types/__tests__/buckets/create_filter/terms.js b/src/ui/public/agg_types/__tests__/buckets/create_filter/terms.js
index c0a67aa283655..50056b516d42e 100644
--- a/src/ui/public/agg_types/__tests__/buckets/create_filter/terms.js
+++ b/src/ui/public/agg_types/__tests__/buckets/create_filter/terms.js
@@ -21,12 +21,12 @@ describe('AggConfig Filters', function () {
     }));
 
     it('should return a match filter for terms', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [ { type: 'terms', schema: 'segment', params: { field: '_type' } } ]
       });
-      let aggConfig = vis.aggs.byTypeName.terms[0];
-      let filter = createFilter(aggConfig, 'apache');
+      const aggConfig = vis.aggs.byTypeName.terms[0];
+      const filter = createFilter(aggConfig, 'apache');
       expect(filter).to.have.property('query');
       expect(filter.query).to.have.property('match');
       expect(filter.query.match).to.have.property('_type');
diff --git a/src/ui/public/agg_types/__tests__/buckets/date_histogram/_editor.js b/src/ui/public/agg_types/__tests__/buckets/date_histogram/_editor.js
index 6d2e4834418eb..62bc7944e747b 100644
--- a/src/ui/public/agg_types/__tests__/buckets/date_histogram/_editor.js
+++ b/src/ui/public/agg_types/__tests__/buckets/date_histogram/_editor.js
@@ -17,7 +17,7 @@ describe('editor', function () {
   beforeEach(ngMock.inject(function (Private, $injector, $compile) {
     indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
 
-    let Vis = Private(VisProvider);
+    const Vis = Private(VisProvider);
 
     /**
      * Render the AggParams editor for the date histogram aggregation
@@ -38,8 +38,8 @@ describe('editor', function () {
         ]
       });
 
-      let $el = $('<vis-editor-agg-params agg="agg" group-name="groupName"></vis-editor-agg-params>');
-      let $parentScope = $injector.get('$rootScope').$new();
+      const $el = $('<vis-editor-agg-params agg="agg" group-name="groupName"></vis-editor-agg-params>');
+      const $parentScope = $injector.get('$rootScope').$new();
 
       agg = $parentScope.agg = vis.aggs.bySchemaName.segment[0];
       $parentScope.groupName = 'buckets';
@@ -48,10 +48,10 @@ describe('editor', function () {
       $scope = $el.scope();
       $scope.$digest();
 
-      let $inputs = $('vis-agg-param-editor', $el);
+      const $inputs = $('vis-agg-param-editor', $el);
       return _.transform($inputs.toArray(), function (inputs, e) {
-        let $el = $(e);
-        let $scope = $el.scope();
+        const $el = $(e);
+        const $scope = $el.scope();
 
         inputs[$scope.aggParam.name] = {
           $el: $el,
@@ -107,7 +107,7 @@ describe('editor', function () {
       expect(params.interval.modelValue().val).to.be('auto');
       expect(params.field.modelValue().name).to.be(indexPattern.timeFieldName);
 
-      let field = _.find(indexPattern.fields, function (f) {
+      const field = _.find(indexPattern.fields, function (f) {
         return f.type === 'date' && f.name !== indexPattern.timeFieldName;
       });
 
diff --git a/src/ui/public/agg_types/__tests__/buckets/date_histogram/_params.js b/src/ui/public/agg_types/__tests__/buckets/date_histogram/_params.js
index 4e6c6870f2574..5a0c06d6811b3 100644
--- a/src/ui/public/agg_types/__tests__/buckets/date_histogram/_params.js
+++ b/src/ui/public/agg_types/__tests__/buckets/date_histogram/_params.js
@@ -18,9 +18,9 @@ describe('params', function () {
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function (Private, $injector) {
-    let AggParamWriter = Private(AggParamWriterProvider);
-    let indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
-    let timefilter = $injector.get('timefilter');
+    const AggParamWriter = Private(AggParamWriterProvider);
+    const indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
+    const timefilter = $injector.get('timefilter');
 
     timeField = indexPattern.timeFieldName;
     aggTypes = Private(AggTypesIndexProvider);
@@ -31,7 +31,7 @@ describe('params', function () {
       return paramWriter.write({ interval: interval, field: timeField });
     };
 
-    let now = moment();
+    const now = moment();
     setTimeBounds = function (n, units) {
       timefilter.enabled = true;
       timefilter.getBounds = _.constant({
@@ -43,24 +43,24 @@ describe('params', function () {
 
   describe('interval', function () {
     it('accepts a valid interval', function () {
-      let output = writeInterval('d');
+      const output = writeInterval('d');
       expect(output.params).to.have.property('interval', '1d');
     });
 
     it('ignores invalid intervals', function () {
-      let output = writeInterval('foo');
+      const output = writeInterval('foo');
       expect(output.params).to.have.property('interval', '0ms');
     });
 
     it('automatically picks an interval', function () {
       setTimeBounds(15, 'm');
-      let output = writeInterval('auto');
+      const output = writeInterval('auto');
       expect(output.params.interval).to.be('30s');
     });
 
     it('scales up the interval if it will make too many buckets', function () {
       setTimeBounds(30, 'm');
-      let output = writeInterval('s');
+      const output = writeInterval('s');
       expect(output.params.interval).to.be('10s');
       expect(output.metricScaleText).to.be('second');
       expect(output.metricScale).to.be(0.1);
@@ -68,30 +68,30 @@ describe('params', function () {
 
     it('does not scale down the interval', function () {
       setTimeBounds(1, 'm');
-      let output = writeInterval('h');
+      const output = writeInterval('h');
       expect(output.params.interval).to.be('1h');
       expect(output.metricScaleText).to.be(undefined);
       expect(output.metricScale).to.be(undefined);
     });
 
     describe('only scales when all metrics are sum or count', function () {
-      let tests = [
+      const tests = [
         [ false, 'avg', 'count', 'sum' ],
         [ true, 'count', 'sum' ],
         [ false, 'count', 'cardinality' ]
       ];
 
       tests.forEach(function (test) {
-        let should = test.shift();
-        let typeNames = test.slice();
+        const should = test.shift();
+        const typeNames = test.slice();
 
         it(typeNames.join(', ') + ' should ' + (should ? '' : 'not') + ' scale', function () {
           setTimeBounds(1, 'y');
 
-          let vis = paramWriter.vis;
+          const vis = paramWriter.vis;
           vis.aggs.splice(0);
 
-          let histoConfig = new AggConfig(vis, {
+          const histoConfig = new AggConfig(vis, {
             type: aggTypes.byName.date_histogram,
             schema: 'segment',
             params: { interval: 's', field: timeField }
@@ -106,7 +106,7 @@ describe('params', function () {
             }));
           });
 
-          let output = histoConfig.write();
+          const output = histoConfig.write();
           expect(_.has(output, 'metricScale')).to.be(should);
         });
       });
@@ -115,9 +115,9 @@ describe('params', function () {
 
   describe('extended_bounds', function () {
     it('should write a long value if a moment passed in', function () {
-      let then = moment(0);
-      let now = moment(500);
-      let output = paramWriter.write({
+      const then = moment(0);
+      const now = moment(500);
+      const output = paramWriter.write({
         extended_bounds: {
           min: then,
           max: now
@@ -133,9 +133,9 @@ describe('params', function () {
     });
 
     it('should write a long if a long is passed', function () {
-      let then = 0;
-      let now = 500;
-      let output = paramWriter.write({
+      const then = 0;
+      const now = 500;
+      const output = paramWriter.write({
         extended_bounds: {
           min: then,
           max: now
diff --git a/src/ui/public/agg_types/__tests__/controls/number_list.js b/src/ui/public/agg_types/__tests__/controls/number_list.js
index 3c7204b0682b8..121501dcbfd7b 100644
--- a/src/ui/public/agg_types/__tests__/controls/number_list.js
+++ b/src/ui/public/agg_types/__tests__/controls/number_list.js
@@ -13,15 +13,15 @@ describe('NumberList directive', function () {
 
   function onlyValidValues() {
     return $el.find('[ng-model]').toArray().map(function (el) {
-      let ngModel = $(el).controller('ngModel');
+      const ngModel = $(el).controller('ngModel');
       return ngModel.$valid ? ngModel.$modelValue : undefined;
     });
   }
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function ($injector) {
-    let $compile = $injector.get('$compile');
-    let $rootScope = $injector.get('$rootScope');
+    const $compile = $injector.get('$compile');
+    const $rootScope = $injector.get('$rootScope');
 
     $scope = $rootScope.$new();
     $el = $('<kbn-number-list ng-model="vals">');
@@ -75,7 +75,7 @@ describe('NumberList directive', function () {
     it('shift-up increases by 0.1', function () {
       compile([4.8]);
 
-      let seq = [
+      const seq = [
         {
           type: 'press',
           key: 'shift',
@@ -111,7 +111,7 @@ describe('NumberList directive', function () {
     it('shift-down decreases by 0.1', function () {
       compile([5.1]);
 
-      let seq = [
+      const seq = [
         {
           type: 'press',
           key: 'shift',
@@ -135,12 +135,12 @@ describe('NumberList directive', function () {
     it('maintains valid number', function () {
       compile([9, 11, 13]);
 
-      let seq = [
+      const seq = [
         'down', // 10 (11 - 1)
         'down'  // 10 (limited by 9)
       ];
 
-      let getEl = function () { return $el.find('input').eq(1); };
+      const getEl = function () { return $el.find('input').eq(1); };
 
       return simulateKeys(getEl, seq)
       .then(function () {
diff --git a/src/ui/public/agg_types/__tests__/metrics/median.js b/src/ui/public/agg_types/__tests__/metrics/median.js
index 3524031c62029..81589c4bf6f48 100644
--- a/src/ui/public/agg_types/__tests__/metrics/median.js
+++ b/src/ui/public/agg_types/__tests__/metrics/median.js
@@ -17,7 +17,7 @@ describe('AggTypeMetricMedianProvider class', function () {
     indexPattern = Private(FixturesStubbedLogstashIndexPatternProvider);
     aggTypeMetricMedian = Private(AggTypeMetricMedianProvider);
 
-    let vis = new Vis(indexPattern, {
+    const vis = new Vis(indexPattern, {
       'title': 'New Visualization',
       'type': 'metric',
       'params': {
@@ -42,7 +42,7 @@ describe('AggTypeMetricMedianProvider class', function () {
 
     // Grab the aggConfig off the vis (we don't actually use the vis for
     // anything else)
-    let aggConfig = vis.aggs[0];
+    const aggConfig = vis.aggs[0];
     aggDsl = aggConfig.toDsl();
   }));
 
diff --git a/src/ui/public/agg_types/__tests__/metrics/std_deviation.js b/src/ui/public/agg_types/__tests__/metrics/std_deviation.js
index 90666b65e5dbd..1433ed793ccaa 100644
--- a/src/ui/public/agg_types/__tests__/metrics/std_deviation.js
+++ b/src/ui/public/agg_types/__tests__/metrics/std_deviation.js
@@ -18,37 +18,37 @@ describe('AggTypeMetricStandardDeviationProvider class', function () {
   }));
 
   it('uses the custom label if it is set', function () {
-    let vis = new Vis(indexPattern, {});
+    const vis = new Vis(indexPattern, {});
 
     // Grab the aggConfig off the vis (we don't actually use the vis for
     // anything else)
-    let aggConfig = vis.aggs[0];
+    const aggConfig = vis.aggs[0];
     aggConfig.params.customLabel = 'custom label';
     aggConfig.params.field = {
       displayName: 'memory'
     };
 
-    let responseAggs = aggTypeMetricStandardDeviation.getResponseAggs(aggConfig);
-    let lowerStdDevLabel = responseAggs[0].makeLabel();
-    let upperStdDevLabel = responseAggs[1].makeLabel();
+    const responseAggs = aggTypeMetricStandardDeviation.getResponseAggs(aggConfig);
+    const lowerStdDevLabel = responseAggs[0].makeLabel();
+    const upperStdDevLabel = responseAggs[1].makeLabel();
 
     expect(lowerStdDevLabel).to.be('Lower custom label');
     expect(upperStdDevLabel).to.be('Upper custom label');
   });
 
   it('uses the default labels if custom label is not set', function () {
-    let vis = new Vis(indexPattern, {});
+    const vis = new Vis(indexPattern, {});
 
     // Grab the aggConfig off the vis (we don't actually use the vis for
     // anything else)
-    let aggConfig = vis.aggs[0];
+    const aggConfig = vis.aggs[0];
     aggConfig.params.field = {
       displayName: 'memory'
     };
 
-    let responseAggs = aggTypeMetricStandardDeviation.getResponseAggs(aggConfig);
-    let lowerStdDevLabel = responseAggs[0].makeLabel();
-    let upperStdDevLabel = responseAggs[1].makeLabel();
+    const responseAggs = aggTypeMetricStandardDeviation.getResponseAggs(aggConfig);
+    const lowerStdDevLabel = responseAggs[0].makeLabel();
+    const upperStdDevLabel = responseAggs[1].makeLabel();
 
     expect(lowerStdDevLabel).to.be('Lower Standard Deviation of memory');
     expect(upperStdDevLabel).to.be('Upper Standard Deviation of memory');
diff --git a/src/ui/public/agg_types/__tests__/param_types/_calculate_interval.js b/src/ui/public/agg_types/__tests__/param_types/_calculate_interval.js
index 47455e418a38a..df28b1a06b2d4 100644
--- a/src/ui/public/agg_types/__tests__/param_types/_calculate_interval.js
+++ b/src/ui/public/agg_types/__tests__/param_types/_calculate_interval.js
@@ -21,15 +21,15 @@ describe('calculateInterval()', function () {
     calculateInterval = Private(AggTypesParamTypesCalculateIntervalProvider);
   }));
 
-  let testInterval = function (option, expected) {
-    let msg = 'should return ' + JSON.stringify(expected) + ' for ' + option;
+  const testInterval = function (option, expected) {
+    const msg = 'should return ' + JSON.stringify(expected) + ' for ' + option;
     it(msg, function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [ { type: 'date_histogram', schema: 'segment', params: { field: '@timestamp', interval: option } } ]
       });
-      let aggConfig = vis.aggs.byTypeName.date_histogram[0];
-      let interval = calculateInterval(aggConfig);
+      const aggConfig = vis.aggs.byTypeName.date_histogram[0];
+      const interval = calculateInterval(aggConfig);
       _.each(expected, function (val, key) {
         expect(interval).to.have.property(key, val);
       });
diff --git a/src/ui/public/agg_types/__tests__/param_types/_field.js b/src/ui/public/agg_types/__tests__/param_types/_field.js
index cc2679fc0d4b8..cf9927ef19ffa 100644
--- a/src/ui/public/agg_types/__tests__/param_types/_field.js
+++ b/src/ui/public/agg_types/__tests__/param_types/_field.js
@@ -17,7 +17,7 @@ describe('Field', function () {
 
   describe('constructor', function () {
     it('it is an instance of BaseAggParam', function () {
-      let aggParam = new FieldAggParam({
+      const aggParam = new FieldAggParam({
         name: 'field'
       });
 
diff --git a/src/ui/public/agg_types/__tests__/param_types/_optioned.js b/src/ui/public/agg_types/__tests__/param_types/_optioned.js
index 69165309fb12d..ad6db067548de 100644
--- a/src/ui/public/agg_types/__tests__/param_types/_optioned.js
+++ b/src/ui/public/agg_types/__tests__/param_types/_optioned.js
@@ -17,7 +17,7 @@ describe('Optioned', function () {
 
   describe('constructor', function () {
     it('it is an instance of BaseAggParam', function () {
-      let aggParam = new OptionedAggParam({
+      const aggParam = new OptionedAggParam({
         name: 'some_param',
         type: 'optioned'
       });
diff --git a/src/ui/public/agg_types/__tests__/param_types/_raw_json.js b/src/ui/public/agg_types/__tests__/param_types/_raw_json.js
index 86c69ee620dad..53bfd8b8a5a8f 100644
--- a/src/ui/public/agg_types/__tests__/param_types/_raw_json.js
+++ b/src/ui/public/agg_types/__tests__/param_types/_raw_json.js
@@ -6,7 +6,7 @@ import AggTypesParamTypesRawJsonProvider from 'ui/agg_types/param_types/raw_json
 
 
 module.exports = describe('JSON', function () {
-  let paramName = 'json_test';
+  const paramName = 'json_test';
   let BaseAggParam;
   let JsonAggParam;
   let aggParam;
@@ -15,7 +15,7 @@ module.exports = describe('JSON', function () {
 
   function initAggParam(config) {
     config = config || {};
-    let defaults = {
+    const defaults = {
       name: paramName,
       type: 'json'
     };
@@ -59,7 +59,7 @@ module.exports = describe('JSON', function () {
     });
 
     it('should append param when valid JSON', function () {
-      let jsonData = JSON.stringify({
+      const jsonData = JSON.stringify({
         new_param: 'should exist in output'
       });
 
@@ -75,7 +75,7 @@ module.exports = describe('JSON', function () {
     });
 
     it('should not overwrite existing params', function () {
-      let jsonData = JSON.stringify({
+      const jsonData = JSON.stringify({
         new_param: 'should exist in output',
         existing: 'should be used'
       });
@@ -88,7 +88,7 @@ module.exports = describe('JSON', function () {
     });
 
     it('should drop nulled params', function () {
-      let jsonData = JSON.stringify({
+      const jsonData = JSON.stringify({
         new_param: 'should exist in output',
         field: null
       });
diff --git a/src/ui/public/agg_types/__tests__/param_types/_regex.js b/src/ui/public/agg_types/__tests__/param_types/_regex.js
index a29c7b7d812e3..d426da4d40db2 100644
--- a/src/ui/public/agg_types/__tests__/param_types/_regex.js
+++ b/src/ui/public/agg_types/__tests__/param_types/_regex.js
@@ -23,7 +23,7 @@ describe('Regex', function () {
 
   describe('constructor', function () {
     it('should be an instance of BaseAggParam', function () {
-      let aggParam = new RegexAggParam({
+      const aggParam = new RegexAggParam({
         name: 'some_param',
         type: 'regex'
       });
@@ -36,11 +36,11 @@ describe('Regex', function () {
   describe('write results', function () {
     let aggParam;
     let aggConfig;
-    let output = { params: {} };
-    let paramName = 'exclude';
+    const output = { params: {} };
+    const paramName = 'exclude';
 
     beforeEach(function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'pie',
         aggs: [
           { type: 'terms', schema: 'split', params: { field: 'extension' }},
diff --git a/src/ui/public/agg_types/__tests__/param_types/_string.js b/src/ui/public/agg_types/__tests__/param_types/_string.js
index fde04e53a2742..01de3883c115c 100644
--- a/src/ui/public/agg_types/__tests__/param_types/_string.js
+++ b/src/ui/public/agg_types/__tests__/param_types/_string.js
@@ -5,7 +5,7 @@ import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 import AggTypesParamTypesStringProvider from 'ui/agg_types/param_types/string';
 
 module.exports = describe('String', function () {
-  let paramName = 'json_test';
+  const paramName = 'json_test';
   let BaseAggParam;
   let StringAggParam;
   let aggParam;
@@ -14,7 +14,7 @@ module.exports = describe('String', function () {
 
   function initAggParam(config) {
     config = config || {};
-    let defaults = {
+    const defaults = {
       name: paramName,
       type: 'string'
     };
@@ -42,8 +42,8 @@ module.exports = describe('String', function () {
 
   describe('write', function () {
     it('should append param by name', function () {
-      let paramName = 'testing';
-      let params = {};
+      const paramName = 'testing';
+      const params = {};
       params[paramName] = 'some input';
 
       initAggParam({ name: paramName });
@@ -55,8 +55,8 @@ module.exports = describe('String', function () {
     });
 
     it('should not be in output with empty input', function () {
-      let paramName = 'more_testing';
-      let params = {};
+      const paramName = 'more_testing';
+      const params = {};
       params[paramName] = '';
 
       initAggParam({ name: paramName });
diff --git a/src/ui/public/agg_types/__tests__/utils/_stub_agg_params.js b/src/ui/public/agg_types/__tests__/utils/_stub_agg_params.js
index c12ced529cf5f..8fdab2c7c66ad 100644
--- a/src/ui/public/agg_types/__tests__/utils/_stub_agg_params.js
+++ b/src/ui/public/agg_types/__tests__/utils/_stub_agg_params.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import sinon from 'auto-release-sinon';
 
 function ParamClassStub(parent, body) {
-  let stub = sinon.spy(body || function () {
+  const stub = sinon.spy(body || function () {
     stub.Super && stub.Super.call(this);
   });
   if (parent) _.class(stub).inherits(parent);
@@ -24,7 +24,7 @@ function ParamClassStub(parent, body) {
  * @return {undefined}
  */
 module.exports = function stubParamClasses(Private) {
-  let BaseAggParam = Private.stub(
+  const BaseAggParam = Private.stub(
     require('ui/agg_types/param_types/base'),
     new ParamClassStub(null, function (config) {
       _.assign(this, config);
diff --git a/src/ui/public/agg_types/agg_params.js b/src/ui/public/agg_types/agg_params.js
index d6c435c214b4c..22e85cf12a73a 100644
--- a/src/ui/public/agg_types/agg_params.js
+++ b/src/ui/public/agg_types/agg_params.js
@@ -10,7 +10,7 @@ import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function AggParamsFactory(Private) {
 
 
-  let paramTypeMap = {
+  const paramTypeMap = {
     field: Private(AggTypesParamTypesFieldProvider),
     optioned: Private(AggTypesParamTypesOptionedProvider),
     regex: Private(AggTypesParamTypesRegexProvider),
@@ -37,8 +37,8 @@ export default function AggParamsFactory(Private) {
     AggParams.Super.call(this, {
       index: ['name'],
       initialSet: params.map(function (config) {
-        let type = config.name === 'field' ? config.name : config.type;
-        let Class = paramTypeMap[type] || paramTypeMap._default;
+        const type = config.name === 'field' ? config.name : config.type;
+        const Class = paramTypeMap[type] || paramTypeMap._default;
         return new Class(config);
       })
     });
@@ -59,7 +59,7 @@ export default function AggParamsFactory(Private) {
    *         are dependent on the AggParam#write methods which should be studied for each AggType.
    */
   AggParams.prototype.write = function (aggConfig, locals) {
-    let output = { params: {} };
+    const output = { params: {} };
     locals = locals || {};
 
     this.forEach(function (param) {
diff --git a/src/ui/public/agg_types/agg_type.js b/src/ui/public/agg_types/agg_type.js
index 64f9db58e33e9..ae08206e14948 100644
--- a/src/ui/public/agg_types/agg_type.js
+++ b/src/ui/public/agg_types/agg_type.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 import AggTypesAggParamsProvider from 'ui/agg_types/agg_params';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function AggTypeFactory(Private) {
-  let AggParams = Private(AggTypesAggParamsProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const AggParams = Private(AggTypesAggParamsProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   /**
    * Generic AggType Constructor
@@ -142,7 +142,7 @@ export default function AggTypeFactory(Private) {
    * @return {FieldFromat}
    */
   AggType.prototype.getFormat = function (agg) {
-    let field = agg.field();
+    const field = agg.field();
     return field ? field.format : fieldFormats.getDefaultInstance('string');
   };
 
diff --git a/src/ui/public/agg_types/buckets/_bucket_agg_type.js b/src/ui/public/agg_types/buckets/_bucket_agg_type.js
index 4249ec29be71e..7f125455906e9 100644
--- a/src/ui/public/agg_types/buckets/_bucket_agg_type.js
+++ b/src/ui/public/agg_types/buckets/_bucket_agg_type.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import AggTypesAggTypeProvider from 'ui/agg_types/agg_type';
 export default function BucketAggTypeProvider(Private) {
-  let AggType = Private(AggTypesAggTypeProvider);
+  const AggType = Private(AggTypesAggTypeProvider);
 
   _.class(BucketAggType).inherits(AggType);
   function BucketAggType(config) {
diff --git a/src/ui/public/agg_types/buckets/_bucket_count_between.js b/src/ui/public/agg_types/buckets/_bucket_count_between.js
index 3fbcd3e723343..2838c8397b8e9 100644
--- a/src/ui/public/agg_types/buckets/_bucket_count_between.js
+++ b/src/ui/public/agg_types/buckets/_bucket_count_between.js
@@ -13,19 +13,19 @@ export default function BucketCountBetweenProvider() {
    * @return {null|number}
    */
   function bucketCountBetween(aggConfigA, aggConfigB) {
-    let aggs = aggConfigA.vis.aggs.getRequestAggs();
+    const aggs = aggConfigA.vis.aggs.getRequestAggs();
 
-    let aIndex = aggs.indexOf(aggConfigA);
-    let bIndex = aggs.indexOf(aggConfigB);
+    const aIndex = aggs.indexOf(aggConfigA);
+    const bIndex = aggs.indexOf(aggConfigB);
 
     if (aIndex === -1 || bIndex === -1) {
       return null;
     }
 
     // return a negative distance, if b is before a
-    let negative = (aIndex > bIndex);
+    const negative = (aIndex > bIndex);
 
-    let count = aggs
+    const count = aggs
       .slice(Math.min(aIndex, bIndex), Math.max(aIndex, bIndex))
       .reduce(function (count, cfg) {
         if (cfg === aggConfigA || cfg === aggConfigB || cfg.schema.group !== 'buckets') {
diff --git a/src/ui/public/agg_types/buckets/_interval_options.js b/src/ui/public/agg_types/buckets/_interval_options.js
index f1a8f151898d2..1a5dcd7da8dd9 100644
--- a/src/ui/public/agg_types/buckets/_interval_options.js
+++ b/src/ui/public/agg_types/buckets/_interval_options.js
@@ -3,7 +3,7 @@ import 'ui/directives/input_whole_number';
 export default function IntervalOptionsService(Private) {
 
   // shorthand
-  let ms = function (type) { return moment.duration(1, type).asMilliseconds(); };
+  const ms = function (type) { return moment.duration(1, type).asMilliseconds(); };
 
   return [
     {
diff --git a/src/ui/public/agg_types/buckets/create_filter/date_histogram.js b/src/ui/public/agg_types/buckets/create_filter/date_histogram.js
index 67b23bbf2e945..2e3f1dc1f0464 100644
--- a/src/ui/public/agg_types/buckets/create_filter/date_histogram.js
+++ b/src/ui/public/agg_types/buckets/create_filter/date_histogram.js
@@ -3,8 +3,8 @@ import buildRangeFilter from 'ui/filter_manager/lib/range';
 export default function createDateHistogramFilterProvider(Private) {
 
   return function (agg, key) {
-    let start = moment(key);
-    let interval = agg.buckets.getInterval();
+    const start = moment(key);
+    const interval = agg.buckets.getInterval();
 
     return buildRangeFilter(agg.params.field, {
       gte: start.valueOf(),
diff --git a/src/ui/public/agg_types/buckets/create_filter/date_range.js b/src/ui/public/agg_types/buckets/create_filter/date_range.js
index 89e8232b6e53e..ac44be29de4b7 100644
--- a/src/ui/public/agg_types/buckets/create_filter/date_range.js
+++ b/src/ui/public/agg_types/buckets/create_filter/date_range.js
@@ -4,9 +4,9 @@ import buildRangeFilter from 'ui/filter_manager/lib/range';
 export default function createDateRangeFilterProvider(config) {
 
   return function (agg, key) {
-    let range = dateRange.parse(key, config.get('dateFormat'));
+    const range = dateRange.parse(key, config.get('dateFormat'));
 
-    let filter = {};
+    const filter = {};
     if (range.from) filter.gte = +range.from;
     if (range.to) filter.lt = +range.to;
     if (range.to && range.from) filter.format = 'epoch_millis';
diff --git a/src/ui/public/agg_types/buckets/create_filter/filters.js b/src/ui/public/agg_types/buckets/create_filter/filters.js
index e9cbde979f2f8..da1726ffbf330 100644
--- a/src/ui/public/agg_types/buckets/create_filter/filters.js
+++ b/src/ui/public/agg_types/buckets/create_filter/filters.js
@@ -3,8 +3,8 @@ import _ from 'lodash';
 export default function CreateFilterFiltersProvider(Private) {
   return function (aggConfig, key) {
     // have the aggConfig write agg dsl params
-    let dslFilters = _.get(aggConfig.toDsl(), 'filters.filters');
-    let filter = dslFilters[key];
+    const dslFilters = _.get(aggConfig.toDsl(), 'filters.filters');
+    const filter = dslFilters[key];
 
     if (filter) {
       return buildQueryFilter(filter.query, aggConfig.vis.indexPattern.id);
diff --git a/src/ui/public/agg_types/buckets/create_filter/histogram.js b/src/ui/public/agg_types/buckets/create_filter/histogram.js
index fd6c8c1e21c16..30c828b7a4567 100644
--- a/src/ui/public/agg_types/buckets/create_filter/histogram.js
+++ b/src/ui/public/agg_types/buckets/create_filter/histogram.js
@@ -2,7 +2,7 @@ import buildRangeFilter from 'ui/filter_manager/lib/range';
 
 export default function createHistogramFilterProvider(Private) {
   return function (aggConfig, key) {
-    let value = parseInt(key, 10);
+    const value = parseInt(key, 10);
 
     return buildRangeFilter(
       aggConfig.params.field,
diff --git a/src/ui/public/agg_types/buckets/create_filter/ip_range.js b/src/ui/public/agg_types/buckets/create_filter/ip_range.js
index ea5efa64adc34..27fc0650ebb95 100644
--- a/src/ui/public/agg_types/buckets/create_filter/ip_range.js
+++ b/src/ui/public/agg_types/buckets/create_filter/ip_range.js
@@ -6,7 +6,7 @@ export default function createIpRangeFilterProvider() {
     if (aggConfig.params.ipRangeType === 'mask') {
       range = new CidrMask(key).getRange();
     } else {
-      let addresses = key.split(/\-/);
+      const addresses = key.split(/\-/);
       range = {
         from: addresses[0],
         to: addresses[1]
diff --git a/src/ui/public/agg_types/buckets/date_range.js b/src/ui/public/agg_types/buckets/date_range.js
index 1101cc72b4398..8f843ba5acbce 100644
--- a/src/ui/public/agg_types/buckets/date_range.js
+++ b/src/ui/public/agg_types/buckets/date_range.js
@@ -7,9 +7,9 @@ import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import dateRangesTemplate from 'ui/agg_types/controls/date_ranges.html';
 
 export default function DateRangeAggDefinition(Private, config) {
-  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  let createFilter = Private(AggTypesBucketsCreateFilterDateRangeProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  const createFilter = Private(AggTypesBucketsCreateFilterDateRangeProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
 
   return new BucketAggType({
@@ -17,7 +17,7 @@ export default function DateRangeAggDefinition(Private, config) {
     title: 'Date Range',
     createFilter: createFilter,
     getKey: function (bucket, key, agg) {
-      let formatter = agg.fieldOwnFormatter('text', fieldFormats.getDefaultInstance('date'));
+      const formatter = agg.fieldOwnFormatter('text', fieldFormats.getDefaultInstance('date'));
       return dateRange.toString(bucket, formatter);
     },
     getFormat: function () {
diff --git a/src/ui/public/agg_types/buckets/filters.js b/src/ui/public/agg_types/buckets/filters.js
index 47ab9c13bd0c7..85ad336b4c023 100644
--- a/src/ui/public/agg_types/buckets/filters.js
+++ b/src/ui/public/agg_types/buckets/filters.js
@@ -5,10 +5,10 @@ import AggTypesBucketsCreateFilterFiltersProvider from 'ui/agg_types/buckets/cre
 import DecorateQueryProvider from 'ui/courier/data_source/_decorate_query';
 import filtersTemplate from 'ui/agg_types/controls/filters.html';
 export default function FiltersAggDefinition(Private, Notifier) {
-  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  let createFilter = Private(AggTypesBucketsCreateFilterFiltersProvider);
-  let decorateQuery = Private(DecorateQueryProvider);
-  let notif = new Notifier({ location: 'Filters Agg' });
+  const BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  const createFilter = Private(AggTypesBucketsCreateFilterFiltersProvider);
+  const decorateQuery = Private(DecorateQueryProvider);
+  const notif = new Notifier({ location: 'Filters Agg' });
 
   return new BucketAggType({
     name: 'filters',
@@ -21,25 +21,25 @@ export default function FiltersAggDefinition(Private, Notifier) {
         editor: filtersTemplate,
         default: [ {input: {}, label: ''} ],
         write: function (aggConfig, output) {
-          let inFilters = aggConfig.params.filters;
+          const inFilters = aggConfig.params.filters;
           if (!_.size(inFilters)) return;
 
-          let outFilters = _.transform(inFilters, function (filters, filter) {
-            let input = filter.input;
+          const outFilters = _.transform(inFilters, function (filters, filter) {
+            const input = filter.input;
             if (!input) return notif.log('malformed filter agg params, missing "input" query');
 
-            let query = input.query;
+            const query = input.query;
             if (!query) return notif.log('malformed filter agg params, missing "query" on input');
 
             decorateQuery(query);
 
-            let label = filter.label || _.get(query, 'query_string.query') || angular.toJson(query);
+            const label = filter.label || _.get(query, 'query_string.query') || angular.toJson(query);
             filters[label] = input;
           }, {});
 
           if (!_.size(outFilters)) return;
 
-          let params = output.params || (output.params = {});
+          const params = output.params || (output.params = {});
           params.filters = outFilters;
         }
       }
diff --git a/src/ui/public/agg_types/buckets/geo_hash.js b/src/ui/public/agg_types/buckets/geo_hash.js
index 230683f4514a2..14c58da476003 100644
--- a/src/ui/public/agg_types/buckets/geo_hash.js
+++ b/src/ui/public/agg_types/buckets/geo_hash.js
@@ -11,7 +11,7 @@ export default function GeoHashAggDefinition(Private, config) {
    * Map Leaflet zoom levels to geohash precision levels.
    * The size of a geohash column-width on the map should be at least `minGeohashPixels` pixels wide.
    */
-  let zoomPrecision = {};
+  const zoomPrecision = {};
   const minGeohashPixels = 16;
   for (let zoom = 0; zoom <= 21; zoom += 1) {
     const worldPixels = 256 * Math.pow(2, zoom);
diff --git a/src/ui/public/agg_types/buckets/histogram.js b/src/ui/public/agg_types/buckets/histogram.js
index bbfd761b15228..647ae2a6d9f89 100644
--- a/src/ui/public/agg_types/buckets/histogram.js
+++ b/src/ui/public/agg_types/buckets/histogram.js
@@ -7,8 +7,8 @@ import intervalTemplate from 'ui/agg_types/controls/interval.html';
 import minDocCountTemplate from 'ui/agg_types/controls/min_doc_count.html';
 import extendedBoundsTemplate from 'ui/agg_types/controls/extended_bounds.html';
 export default function HistogramAggDefinition(Private) {
-  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  let createFilter = Private(AggTypesBucketsCreateFilterHistogramProvider);
+  const BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  const createFilter = Private(AggTypesBucketsCreateFilterHistogramProvider);
 
 
   return new BucketAggType({
@@ -49,7 +49,7 @@ export default function HistogramAggDefinition(Private) {
         default: {},
         editor: extendedBoundsTemplate,
         write: function (aggConfig, output) {
-          let val = aggConfig.params.extended_bounds;
+          const val = aggConfig.params.extended_bounds;
 
           if (aggConfig.params.min_doc_count && (val.min != null || val.max != null)) {
             output.params.extended_bounds = {
@@ -61,7 +61,7 @@ export default function HistogramAggDefinition(Private) {
 
         // called from the editor
         shouldShow: function (aggConfig) {
-          let field = aggConfig.params.field;
+          const field = aggConfig.params.field;
           if (
             field
             && (field.type === 'number' || field.type === 'date')
diff --git a/src/ui/public/agg_types/buckets/ip_range.js b/src/ui/public/agg_types/buckets/ip_range.js
index ea1a446101625..7d4e8906445ab 100644
--- a/src/ui/public/agg_types/buckets/ip_range.js
+++ b/src/ui/public/agg_types/buckets/ip_range.js
@@ -6,8 +6,8 @@ import AggTypesBucketsCreateFilterIpRangeProvider from 'ui/agg_types/buckets/cre
 import ipRangesTemplate from 'ui/agg_types/controls/ip_ranges.html';
 
 export default function RangeAggDefinition(Private) {
-  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  let createFilter = Private(AggTypesBucketsCreateFilterIpRangeProvider);
+  const BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  const createFilter = Private(AggTypesBucketsCreateFilterIpRangeProvider);
 
   return new BucketAggType({
     name: 'ip_range',
@@ -38,7 +38,7 @@ export default function RangeAggDefinition(Private) {
         },
         editor: ipRangesTemplate,
         write: function (aggConfig, output) {
-          let ipRangeType = aggConfig.params.ipRangeType;
+          const ipRangeType = aggConfig.params.ipRangeType;
           output.params.ranges = aggConfig.params.ranges[ipRangeType];
         }
       }
diff --git a/src/ui/public/agg_types/buckets/range.js b/src/ui/public/agg_types/buckets/range.js
index ec6d33935b7c8..9530dfd8e2c4f 100644
--- a/src/ui/public/agg_types/buckets/range.js
+++ b/src/ui/public/agg_types/buckets/range.js
@@ -5,13 +5,13 @@ import IndexPatternsFieldFormatFieldFormatProvider from 'ui/index_patterns/_fiel
 import RangeKeyProvider from './range_key';
 import rangesTemplate from 'ui/agg_types/controls/ranges.html';
 export default function RangeAggDefinition(Private) {
-  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  let createFilter = Private(AggTypesBucketsCreateFilterRangeProvider);
-  let FieldFormat = Private(IndexPatternsFieldFormatFieldFormatProvider);
-  let RangeKey = Private(RangeKeyProvider);
+  const BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  const createFilter = Private(AggTypesBucketsCreateFilterRangeProvider);
+  const FieldFormat = Private(IndexPatternsFieldFormatFieldFormatProvider);
+  const RangeKey = Private(RangeKeyProvider);
 
-  let keyCaches = new WeakMap();
-  let formats = new WeakMap();
+  const keyCaches = new WeakMap();
+  const formats = new WeakMap();
 
   return new BucketAggType({
     name: 'range',
@@ -28,7 +28,7 @@ export default function RangeAggDefinition(Private) {
         keyCaches.set(agg, keys);
       }
 
-      let id = RangeKey.idBucket(bucket);
+      const id = RangeKey.idBucket(bucket);
 
       key = keys.get(id);
       if (!key) {
@@ -42,8 +42,8 @@ export default function RangeAggDefinition(Private) {
       let format = formats.get(agg);
       if (format) return format;
 
-      let RangeFormat = FieldFormat.from(function (range) {
-        let format = agg.fieldOwnFormatter();
+      const RangeFormat = FieldFormat.from(function (range) {
+        const format = agg.fieldOwnFormatter();
         return `${format(range.gte)} to ${format(range.lt)}`;
       });
 
diff --git a/src/ui/public/agg_types/buckets/significant_terms.js b/src/ui/public/agg_types/buckets/significant_terms.js
index 36fe87d970d8c..ef28f963da0e1 100644
--- a/src/ui/public/agg_types/buckets/significant_terms.js
+++ b/src/ui/public/agg_types/buckets/significant_terms.js
@@ -3,8 +3,8 @@ import AggTypesBucketsBucketAggTypeProvider from 'ui/agg_types/buckets/_bucket_a
 import AggTypesBucketsCreateFilterTermsProvider from 'ui/agg_types/buckets/create_filter/terms';
 import orderAndSizeTemplate from 'ui/agg_types/controls/order_and_size.html';
 export default function SignificantTermsAggDefinition(Private) {
-  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  let createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
+  const BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  const createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
 
   return new BucketAggType({
     name: 'significant_terms',
diff --git a/src/ui/public/agg_types/buckets/terms.js b/src/ui/public/agg_types/buckets/terms.js
index 4a81cbbf939ff..645cc59d673a9 100644
--- a/src/ui/public/agg_types/buckets/terms.js
+++ b/src/ui/public/agg_types/buckets/terms.js
@@ -7,13 +7,13 @@ import AggTypesBucketsCreateFilterTermsProvider from 'ui/agg_types/buckets/creat
 import orderAggTemplate from 'ui/agg_types/controls/order_agg.html';
 import orderAndSizeTemplate from 'ui/agg_types/controls/order_and_size.html';
 export default function TermsAggDefinition(Private) {
-  let BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
-  let bucketCountBetween = Private(AggTypesBucketsBucketCountBetweenProvider);
-  let AggConfig = Private(VisAggConfigProvider);
-  let Schemas = Private(VisSchemasProvider);
-  let createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
+  const BucketAggType = Private(AggTypesBucketsBucketAggTypeProvider);
+  const bucketCountBetween = Private(AggTypesBucketsBucketCountBetweenProvider);
+  const AggConfig = Private(VisAggConfigProvider);
+  const Schemas = Private(VisSchemasProvider);
+  const createFilter = Private(AggTypesBucketsCreateFilterTermsProvider);
 
-  let orderAggSchema = (new Schemas([
+  const orderAggSchema = (new Schemas([
     {
       group: 'none',
       name: 'orderAgg',
@@ -24,7 +24,7 @@ export default function TermsAggDefinition(Private) {
 
   function isNotType(type) {
     return function (agg) {
-      let field = agg.params.field;
+      const field = agg.params.field;
       return !field || field.type !== type;
     };
   }
@@ -33,7 +33,7 @@ export default function TermsAggDefinition(Private) {
     name: 'terms',
     title: 'Terms',
     makeLabel: function (agg) {
-      let params = agg.params;
+      const params = agg.params;
       return params.field.displayName + ': ' + params.order.display;
     },
     createFilter: createFilter,
@@ -73,7 +73,7 @@ export default function TermsAggDefinition(Private) {
         makeOrderAgg: function (termsAgg, state) {
           state = state || {};
           state.schema = orderAggSchema;
-          let orderAgg = new AggConfig(termsAgg.vis, state);
+          const orderAgg = new AggConfig(termsAgg.vis, state);
           orderAgg.id = termsAgg.id + '-orderAgg';
           return orderAgg;
         },
@@ -86,18 +86,18 @@ export default function TermsAggDefinition(Private) {
             }
           };
 
-          let INIT = {}; // flag to know when prevOrderBy has changed
+          const INIT = {}; // flag to know when prevOrderBy has changed
           let prevOrderBy = INIT;
 
           $scope.$watch('responseValueAggs', updateOrderAgg);
           $scope.$watch('agg.params.orderBy', updateOrderAgg);
 
           function updateOrderAgg() {
-            let agg = $scope.agg;
-            let aggs = agg.vis.aggs;
-            let params = agg.params;
-            let orderBy = params.orderBy;
-            let paramDef = agg.type.params.byName.orderAgg;
+            const agg = $scope.agg;
+            const aggs = agg.vis.aggs;
+            const params = agg.params;
+            const orderBy = params.orderBy;
+            const paramDef = agg.type.params.byName.orderAgg;
 
             // setup the initial value of orderBy
             if (!orderBy && prevOrderBy === INIT) {
@@ -130,9 +130,9 @@ export default function TermsAggDefinition(Private) {
           }
         },
         write: function (agg, output) {
-          let vis = agg.vis;
-          let dir = agg.params.order.val;
-          let order = output.params.order = {};
+          const vis = agg.vis;
+          const dir = agg.params.order.val;
+          const order = output.params.order = {};
 
           let orderAgg = agg.params.orderAgg || vis.aggs.getResponseAggById(agg.params.orderBy);
 
@@ -153,7 +153,7 @@ export default function TermsAggDefinition(Private) {
             return;
           }
 
-          let orderAggId = orderAgg.id;
+          const orderAggId = orderAgg.id;
           if (orderAgg.parentId) {
             orderAgg = vis.aggs.byId[orderAgg.parentId];
           }
diff --git a/src/ui/public/agg_types/index.js b/src/ui/public/agg_types/index.js
index 762a9dbab4a99..ad7af3709460e 100644
--- a/src/ui/public/agg_types/index.js
+++ b/src/ui/public/agg_types/index.js
@@ -21,7 +21,7 @@ import AggTypesBucketsSignificantTermsProvider from 'ui/agg_types/buckets/signif
 import AggTypesBucketsGeoHashProvider from 'ui/agg_types/buckets/geo_hash';
 export default function AggTypeService(Private) {
 
-  let aggs = {
+  const aggs = {
     metrics: [
       Private(AggTypesMetricsCountProvider),
       Private(AggTypesMetricsAvgProvider),
diff --git a/src/ui/public/agg_types/metrics/avg.js b/src/ui/public/agg_types/metrics/avg.js
index f313464433da1..1550fc964fc5b 100644
--- a/src/ui/public/agg_types/metrics/avg.js
+++ b/src/ui/public/agg_types/metrics/avg.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricAvgProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'avg',
diff --git a/src/ui/public/agg_types/metrics/cardinality.js b/src/ui/public/agg_types/metrics/cardinality.js
index 8ff6d93f61924..d76f83bcaf8df 100644
--- a/src/ui/public/agg_types/metrics/cardinality.js
+++ b/src/ui/public/agg_types/metrics/cardinality.js
@@ -2,8 +2,8 @@ import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_ag
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 
 export default function AggTypeMetricCardinalityProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   return new MetricAggType({
     name: 'cardinality',
diff --git a/src/ui/public/agg_types/metrics/count.js b/src/ui/public/agg_types/metrics/count.js
index fcad3d8dffa06..2e76b8fc5c2d3 100644
--- a/src/ui/public/agg_types/metrics/count.js
+++ b/src/ui/public/agg_types/metrics/count.js
@@ -2,8 +2,8 @@ import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_ag
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 
 export default function AggTypeMetricCountProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   return new MetricAggType({
     name: 'count',
diff --git a/src/ui/public/agg_types/metrics/get_response_agg_config_class.js b/src/ui/public/agg_types/metrics/get_response_agg_config_class.js
index b9112f343e81b..07a54b2366b64 100644
--- a/src/ui/public/agg_types/metrics/get_response_agg_config_class.js
+++ b/src/ui/public/agg_types/metrics/get_response_agg_config_class.js
@@ -30,7 +30,7 @@ export default function ResponseAggConfigProvider() {
       this.key = key;
       this.parentId = this.id;
 
-      let subId = String(key);
+      const subId = String(key);
       if (subId.indexOf('.') > -1) {
         this.id = this.parentId + '[\'' + subId.replace(/'/g, '\\\'') + '\']';
       } else {
diff --git a/src/ui/public/agg_types/metrics/max.js b/src/ui/public/agg_types/metrics/max.js
index 938ee8d4a45e7..b360a2b5dac75 100644
--- a/src/ui/public/agg_types/metrics/max.js
+++ b/src/ui/public/agg_types/metrics/max.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricMaxProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'max',
diff --git a/src/ui/public/agg_types/metrics/median.js b/src/ui/public/agg_types/metrics/median.js
index 1564aeba278ad..e489f5d28f39e 100644
--- a/src/ui/public/agg_types/metrics/median.js
+++ b/src/ui/public/agg_types/metrics/median.js
@@ -3,9 +3,9 @@ import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_ag
 import AggTypesMetricsGetResponseAggConfigClassProvider from 'ui/agg_types/metrics/get_response_agg_config_class';
 import AggTypesMetricsPercentilesProvider from 'ui/agg_types/metrics/percentiles';
 export default function AggTypeMetricMedianProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
-  let percentiles = Private(AggTypesMetricsPercentilesProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  const percentiles = Private(AggTypesMetricsPercentilesProvider);
 
   return new MetricAggType({
     name: 'median',
diff --git a/src/ui/public/agg_types/metrics/metric_agg_type.js b/src/ui/public/agg_types/metrics/metric_agg_type.js
index e9d03f60f3356..bb39beb086862 100644
--- a/src/ui/public/agg_types/metrics/metric_agg_type.js
+++ b/src/ui/public/agg_types/metrics/metric_agg_type.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 import AggTypesAggTypeProvider from 'ui/agg_types/agg_type';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function MetricAggTypeProvider(Private) {
-  let AggType = Private(AggTypesAggTypeProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const AggType = Private(AggTypesAggTypeProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   _.class(MetricAggType).inherits(AggType);
   function MetricAggType(config) {
@@ -24,7 +24,7 @@ export default function MetricAggTypeProvider(Private) {
    */
   MetricAggType.prototype.getValue = function (agg, bucket) {
     // Metric types where an empty set equals `zero`
-    let isSettableToZero = ['cardinality', 'sum'].indexOf(agg.__type.name) !== -1;
+    const isSettableToZero = ['cardinality', 'sum'].indexOf(agg.__type.name) !== -1;
 
     // Return proper values when no buckets are present
     // `Count` handles empty sets properly
@@ -42,7 +42,7 @@ export default function MetricAggTypeProvider(Private) {
    * @return {FieldFromat}
    */
   MetricAggType.prototype.getFormat = function (agg) {
-    let field = agg.field();
+    const field = agg.field();
     return field ? field.format : fieldFormats.getDefaultInstance('number');
   };
 
diff --git a/src/ui/public/agg_types/metrics/min.js b/src/ui/public/agg_types/metrics/min.js
index a14593af1dd01..7c1a19dbabaf4 100644
--- a/src/ui/public/agg_types/metrics/min.js
+++ b/src/ui/public/agg_types/metrics/min.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricMinProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'min',
diff --git a/src/ui/public/agg_types/metrics/percentile_ranks.js b/src/ui/public/agg_types/metrics/percentile_ranks.js
index 4400873b2c620..0e057533dcbd5 100644
--- a/src/ui/public/agg_types/metrics/percentile_ranks.js
+++ b/src/ui/public/agg_types/metrics/percentile_ranks.js
@@ -7,16 +7,16 @@ import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import getPercentileValue from './percentiles_get_value';
 
 export default function AggTypeMetricPercentileRanksProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   // required by the values editor
 
-  let valueProps = {
+  const valueProps = {
     makeLabel: function () {
-      let field = this.field();
-      let format = (field && field.format) || fieldFormats.getDefaultInstance('number');
+      const field = this.field();
+      const format = (field && field.format) || fieldFormats.getDefaultInstance('number');
       const label = this.params.customLabel || this.fieldDisplayName();
 
       return 'Percentile rank ' + format.convert(this.key, 'text') + ' of "' + label + '"';
@@ -46,7 +46,7 @@ export default function AggTypeMetricPercentileRanksProvider(Private) {
       }
     ],
     getResponseAggs: function (agg) {
-      let ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
+      const ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
 
       return agg.params.values.map(function (value) {
         return new ValueAggConfig(value);
diff --git a/src/ui/public/agg_types/metrics/percentiles.js b/src/ui/public/agg_types/metrics/percentiles.js
index 59ba2da34387f..b6ef168db5831 100644
--- a/src/ui/public/agg_types/metrics/percentiles.js
+++ b/src/ui/public/agg_types/metrics/percentiles.js
@@ -8,13 +8,13 @@ import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import getPercentileValue from './percentiles_get_value';
 
 export default function AggTypeMetricPercentilesProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   // required by the percentiles editor
 
-  let valueProps = {
+  const valueProps = {
     makeLabel: function () {
       const label = this.params.customLabel || this.fieldDisplayName();
       return ordinalSuffix(this.key) + ' percentile of ' + label;
@@ -44,7 +44,7 @@ export default function AggTypeMetricPercentilesProvider(Private) {
       }
     ],
     getResponseAggs: function (agg) {
-      let ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
+      const ValueAggConfig = getResponseAggConfigClass(agg, valueProps);
 
       return agg.params.percents.map(function (percent) {
         return new ValueAggConfig(percent);
diff --git a/src/ui/public/agg_types/metrics/std_deviation.js b/src/ui/public/agg_types/metrics/std_deviation.js
index c28b700aed296..8976fedc8af04 100644
--- a/src/ui/public/agg_types/metrics/std_deviation.js
+++ b/src/ui/public/agg_types/metrics/std_deviation.js
@@ -2,12 +2,12 @@ import _ from 'lodash';
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 import AggTypesMetricsGetResponseAggConfigClassProvider from 'ui/agg_types/metrics/get_response_agg_config_class';
 export default function AggTypeMetricStandardDeviationProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
-  let getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const getResponseAggConfigClass = Private(AggTypesMetricsGetResponseAggConfigClassProvider);
 
-  let responseAggConfigProps = {
+  const responseAggConfigProps = {
     valProp: function () {
-      let details = this.keyedDetails(this.params.customLabel)[this.key];
+      const details = this.keyedDetails(this.params.customLabel)[this.key];
       return details.valProp;
     },
     makeLabel: function () {
@@ -45,7 +45,7 @@ export default function AggTypeMetricStandardDeviationProvider(Private) {
     ],
 
     getResponseAggs: function (agg) {
-      let ValueAggConfig = getResponseAggConfigClass(agg, responseAggConfigProps);
+      const ValueAggConfig = getResponseAggConfigClass(agg, responseAggConfigProps);
 
       return [
         new ValueAggConfig('std_lower'),
diff --git a/src/ui/public/agg_types/metrics/sum.js b/src/ui/public/agg_types/metrics/sum.js
index d419edb241e65..bca621988a74e 100644
--- a/src/ui/public/agg_types/metrics/sum.js
+++ b/src/ui/public/agg_types/metrics/sum.js
@@ -1,7 +1,7 @@
 import AggTypesMetricsMetricAggTypeProvider from 'ui/agg_types/metrics/metric_agg_type';
 
 export default function AggTypeMetricSumProvider(Private) {
-  let MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
+  const MetricAggType = Private(AggTypesMetricsMetricAggTypeProvider);
 
   return new MetricAggType({
     name: 'sum',
diff --git a/src/ui/public/agg_types/param_types/field.js b/src/ui/public/agg_types/param_types/field.js
index 4b61581b5b419..4ac1d0f8cabb9 100644
--- a/src/ui/public/agg_types/param_types/field.js
+++ b/src/ui/public/agg_types/param_types/field.js
@@ -4,7 +4,7 @@ import editorHtml from 'ui/agg_types/controls/field.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function FieldAggParamFactory(Private) {
 
-  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  const BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(FieldAggParam).inherits(BaseAggParam);
   function FieldAggParam(config) {
@@ -33,7 +33,7 @@ export default function FieldAggParamFactory(Private) {
    * @return {field}
    */
   FieldAggParam.prototype.deserialize = function (fieldName, aggConfig) {
-    let field = aggConfig.vis.indexPattern.fields.byName[fieldName];
+    const field = aggConfig.vis.indexPattern.fields.byName[fieldName];
 
     if (!field) {
       throw new SavedObjectNotFound('index-pattern-field', fieldName);
@@ -53,7 +53,7 @@ export default function FieldAggParamFactory(Private) {
    * @return {undefined}
    */
   FieldAggParam.prototype.write = function (aggConfig, output) {
-    let field = aggConfig.params.field;
+    const field = aggConfig.params.field;
 
     if (field.scripted) {
       output.params.script = {
diff --git a/src/ui/public/agg_types/param_types/optioned.js b/src/ui/public/agg_types/param_types/optioned.js
index 2e161a879a6c5..7fb0f06bf6c95 100644
--- a/src/ui/public/agg_types/param_types/optioned.js
+++ b/src/ui/public/agg_types/param_types/optioned.js
@@ -3,7 +3,7 @@ import IndexedArray from 'ui/indexed_array';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function OptionedAggParamFactory(Private) {
 
-  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  const BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(OptionedAggParam).inherits(BaseAggParam);
   function OptionedAggParam(config) {
diff --git a/src/ui/public/agg_types/param_types/raw_json.js b/src/ui/public/agg_types/param_types/raw_json.js
index 25f160174230d..b865b2312c896 100644
--- a/src/ui/public/agg_types/param_types/raw_json.js
+++ b/src/ui/public/agg_types/param_types/raw_json.js
@@ -3,7 +3,7 @@ import editorHtml from 'ui/agg_types/controls/raw_json.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function RawJSONAggParamFactory(Private) {
 
-  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  const BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(RawJSONAggParam).inherits(BaseAggParam);
   function RawJSONAggParam(config) {
@@ -26,7 +26,7 @@ export default function RawJSONAggParamFactory(Private) {
    */
   RawJSONAggParam.prototype.write = function (aggConfig, output) {
     let paramJSON;
-    let param = aggConfig.params[this.name];
+    const param = aggConfig.params[this.name];
 
     if (!param) {
       return;
@@ -45,7 +45,7 @@ export default function RawJSONAggParamFactory(Private) {
         .keys()
         .union(_.keys(b))
         .transform(function (dest, key) {
-          let val = compare(a[key], b[key]);
+          const val = compare(a[key], b[key]);
           if (val !== undefined) dest[key] = val;
         }, {})
         .value();
diff --git a/src/ui/public/agg_types/param_types/regex.js b/src/ui/public/agg_types/param_types/regex.js
index 3a38c06f8b9da..b00c6f654ea37 100644
--- a/src/ui/public/agg_types/param_types/regex.js
+++ b/src/ui/public/agg_types/param_types/regex.js
@@ -3,7 +3,7 @@ import editorHtml from 'ui/agg_types/controls/regular_expression.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function RegexAggParamFactory(Private) {
 
-  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  const BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(RegexAggParam).inherits(BaseAggParam);
   function RegexAggParam(config) {
@@ -33,15 +33,15 @@ export default function RegexAggParamFactory(Private) {
    * @return {undefined}
    */
   RegexAggParam.prototype.write = function (aggConfig, output) {
-    let param = aggConfig.params[this.name];
-    let paramType = aggConfig.type.params.byName[this.name];
+    const param = aggConfig.params[this.name];
+    const paramType = aggConfig.type.params.byName[this.name];
 
     // clear aggParam if pattern is not set or is disabled
     if (!param || !param.pattern || !param.pattern.length || paramType.disabled(aggConfig)) {
       return;
     }
 
-    let obj = {
+    const obj = {
       pattern: param.pattern
     };
 
diff --git a/src/ui/public/agg_types/param_types/string.js b/src/ui/public/agg_types/param_types/string.js
index 58803171c44a4..dc15d9eefdbdb 100644
--- a/src/ui/public/agg_types/param_types/string.js
+++ b/src/ui/public/agg_types/param_types/string.js
@@ -3,7 +3,7 @@ import editorHtml from 'ui/agg_types/controls/string.html';
 import AggTypesParamTypesBaseProvider from 'ui/agg_types/param_types/base';
 export default function FieldAggParamFactory(Private) {
 
-  let BaseAggParam = Private(AggTypesParamTypesBaseProvider);
+  const BaseAggParam = Private(AggTypesParamTypesBaseProvider);
 
   _.class(ScriptAggParam).inherits(BaseAggParam);
   function ScriptAggParam(config) {
diff --git a/src/ui/public/bind/__tests__/bind.js b/src/ui/public/bind/__tests__/bind.js
index e7acb9b037080..ad00339c6a033 100644
--- a/src/ui/public/bind/__tests__/bind.js
+++ b/src/ui/public/bind/__tests__/bind.js
@@ -16,7 +16,7 @@ describe('$scope.$bind', function () {
     expect($rootScope.$bind).to.be.a('function');
     expect($scope).to.have.property('$bind', $rootScope.$bind);
 
-    let $isoScope = $scope.$new(true);
+    const $isoScope = $scope.$new(true);
     expect($isoScope).to.have.property('$bind', $rootScope.$bind);
   });
 
@@ -33,7 +33,7 @@ describe('$scope.$bind', function () {
   });
 
   it('sets up a binding from the child to the parent scope', function () {
-    let stub = sinon.stub();
+    const stub = sinon.stub();
 
     $rootScope.val = 'foo';
     $scope.$bind('localVal', 'val');
@@ -47,8 +47,8 @@ describe('$scope.$bind', function () {
   });
 
   it('pulls from the scopes $parent by default', function () {
-    let $parent = $rootScope.$new();
-    let $self = $parent.$new();
+    const $parent = $rootScope.$new();
+    const $self = $parent.$new();
 
     $parent.val = 'foo';
     $self.val = 'bar';
@@ -58,8 +58,8 @@ describe('$scope.$bind', function () {
   });
 
   it('accepts an alternate scope to read from', function () {
-    let $parent = $rootScope.$new();
-    let $self = $parent.$new();
+    const $parent = $rootScope.$new();
+    const $self = $parent.$new();
 
     $parent.val = 'foo';
     $self.val = 'bar';
diff --git a/src/ui/public/bind/bind.js b/src/ui/public/bind/bind.js
index ba16ddc5bfdcb..5d8afb8509d25 100644
--- a/src/ui/public/bind/bind.js
+++ b/src/ui/public/bind/bind.js
@@ -27,19 +27,19 @@ uiModules.get('kibana')
      * @return {undefined}
      */
     $delegate.constructor.prototype.$bind = function (to, from, $sourceScope) {
-      let $source = $sourceScope || this.$parent;
-      let $target = this;
+      const $source = $sourceScope || this.$parent;
+      const $target = this;
 
       // parse expressions
-      let $to = $parse(to);
+      const $to = $parse(to);
       if (!$to.assign) errorNotAssignable(to, from);
-      let $from = $parse(from);
+      const $from = $parse(from);
 
       // bind scopes to expressions
-      let getTarget = function () { return $to($target); };
-      let setTarget = function (v) { return $to.assign($target, v); };
-      let getSource = function () { return $from($source); };
-      let setSource = function (v) { return $from.assignOrFail($source, v); };
+      const getTarget = function () { return $to($target); };
+      const setTarget = function (v) { return $to.assign($target, v); };
+      const getSource = function () { return $from($source); };
+      const setSource = function (v) { return $from.assignOrFail($source, v); };
 
       // to support writing from the child to the parent we need to know
       // which source has changed. Track the source value and anytime it
@@ -55,19 +55,19 @@ uiModules.get('kibana')
       };
 
       // if we are syncing down a literal, then we use loose equality check
-      let strict = !$from.literal;
-      let compare = strict ? strictEquality : angular.equals;
+      const strict = !$from.literal;
+      const compare = strict ? strictEquality : angular.equals;
 
 
       // push the initial value down, start off in sync
       setTarget(lastSourceVal);
 
       $target.$watch(function () {
-        let sourceVal = getSource();
-        let targetVal = getTarget();
+        const sourceVal = getSource();
+        const targetVal = getTarget();
 
-        let outOfSync = !compare(sourceVal, targetVal);
-        let sourceChanged = outOfSync && !compare(sourceVal, lastSourceVal);
+        const outOfSync = !compare(sourceVal, targetVal);
+        const sourceChanged = outOfSync && !compare(sourceVal, lastSourceVal);
 
         if (sourceChanged) setTarget(sourceVal);
         else if (outOfSync) setSource(targetVal);
diff --git a/src/ui/public/binder/__tests__/binder.js b/src/ui/public/binder/__tests__/binder.js
index 182050bb597fd..97d518a6008d9 100644
--- a/src/ui/public/binder/__tests__/binder.js
+++ b/src/ui/public/binder/__tests__/binder.js
@@ -16,13 +16,13 @@ describe('Binder class', function () {
   context('Constructing with a $scope', function () {
     it('accepts a $scope and listens for $destroy', function () {
       sinon.stub($scope, '$on');
-      let binder = new Binder($scope);
+      const binder = new Binder($scope);
       expect($scope.$on.callCount).to.be(1);
       expect($scope.$on.args[0][0]).to.be('$destroy');
     });
 
     it('unbinds when the $scope is destroyed', function () {
-      let binder = new Binder($scope);
+      const binder = new Binder($scope);
       sinon.stub(binder, 'destroy');
       $scope.$destroy();
       expect(binder.destroy.callCount).to.be(1);
@@ -31,12 +31,12 @@ describe('Binder class', function () {
 
   describe('Binder#on', function () {
     it('binds to normal event emitters', function () {
-      let binder = new Binder();
-      let emitter = {
+      const binder = new Binder();
+      const emitter = {
         on: sinon.stub(),
         removeListener: sinon.stub()
       };
-      let handler = sinon.stub();
+      const handler = sinon.stub();
 
       binder.on(emitter, 'click', handler);
       expect(emitter.on.callCount).to.be(1);
@@ -52,9 +52,9 @@ describe('Binder class', function () {
 
   describe('Binder#jqOn', function () {
     it('binds jquery event handlers', function () {
-      let binder = new Binder();
-      let el = document.createElement('div');
-      let handler = sinon.stub();
+      const binder = new Binder();
+      const el = document.createElement('div');
+      const handler = sinon.stub();
 
       binder.jqOn(el, 'click', handler);
       $(el).click();
diff --git a/src/ui/public/chrome/__tests__/nav_controls.js b/src/ui/public/chrome/__tests__/nav_controls.js
index dda0bdc483465..921ee5e7710f9 100644
--- a/src/ui/public/chrome/__tests__/nav_controls.js
+++ b/src/ui/public/chrome/__tests__/nav_controls.js
@@ -36,7 +36,7 @@ describe('chrome nav controls', function () {
       };
     });
 
-    let $el = compile();
+    const $el = compile();
     expect($el.find('#testTemplateEl')).to.have.length(1);
   });
 
@@ -63,7 +63,7 @@ describe('chrome nav controls', function () {
       };
     });
 
-    let $el = compile();
+    const $el = compile();
     expect(
       $el.find('.testControl')
       .toArray()
diff --git a/src/ui/public/chrome/api/angular.js b/src/ui/public/chrome/api/angular.js
index e8f9b30115e6b..945c97ee54d5e 100644
--- a/src/ui/public/chrome/api/angular.js
+++ b/src/ui/public/chrome/api/angular.js
@@ -13,7 +13,7 @@ module.exports = function (chrome, internals) {
   chrome.getBreadcrumbs = _.noop;
 
   chrome.setupAngular = function () {
-    let kibana = modules.get('kibana');
+    const kibana = modules.get('kibana');
 
     _.forOwn(chrome.getInjected(), function (val, name) {
       kibana.value(name, val);
@@ -28,7 +28,7 @@ module.exports = function (chrome, internals) {
     .value('sessionId', Date.now())
     .value('chrome', chrome)
     .value('esUrl', (function () {
-      let a = document.createElement('a');
+      const a = document.createElement('a');
       a.href = chrome.addBasePath('/elasticsearch');
       return a.href;
     }()))
@@ -39,7 +39,7 @@ module.exports = function (chrome, internals) {
       };
 
       chrome.getBreadcrumbs = () => {
-        let path = $location.path();
+        const path = $location.path();
         let length = path.length - 1;
 
         // trim trailing slash
diff --git a/src/ui/public/chrome/api/nav.js b/src/ui/public/chrome/api/nav.js
index f66db80a634e5..b592eaf0eb019 100644
--- a/src/ui/public/chrome/api/nav.js
+++ b/src/ui/public/chrome/api/nav.js
@@ -19,10 +19,10 @@ export default function (chrome, internals) {
   };
 
   chrome.addBasePath = function (url) {
-    let isUrl = url && isString(url);
+    const isUrl = url && isString(url);
     if (!isUrl) return url;
 
-    let parsed = parse(url, true, true);
+    const parsed = parse(url, true, true);
     if (!parsed.host && parsed.pathname) {
       if (parsed.pathname[0] === '/') {
         parsed.pathname = chrome.getBasePath() + parsed.pathname;
@@ -126,7 +126,7 @@ export default function (chrome, internals) {
 
   internals.nav.forEach(link => {
     // convert all link urls to absolute urls
-    let a = document.createElement('a');
+    const a = document.createElement('a');
     a.setAttribute('href', link.url);
     link.url = a.href;
   });
diff --git a/src/ui/public/chrome/api/theme.js b/src/ui/public/chrome/api/theme.js
index 192239cd91488..f2fee099ad015 100644
--- a/src/ui/public/chrome/api/theme.js
+++ b/src/ui/public/chrome/api/theme.js
@@ -81,8 +81,8 @@ module.exports = function (chrome, internals) {
    * @return {chrome}
    */
   chrome.removeApplicationClass = function (val) {
-    let classesToRemove = [].concat(val || []);
-    let classes = internals.applicationClasses || [];
+    const classesToRemove = [].concat(val || []);
+    const classes = internals.applicationClasses || [];
     _.pull(classes, ...classesToRemove);
 
     internals.applicationClasses = classes;
diff --git a/src/ui/public/chrome/directives/global_nav/app_switcher/__tests__/app_switcher.js b/src/ui/public/chrome/directives/global_nav/app_switcher/__tests__/app_switcher.js
index 3f0dac3370d89..19c8d7f62a732 100644
--- a/src/ui/public/chrome/directives/global_nav/app_switcher/__tests__/app_switcher.js
+++ b/src/ui/public/chrome/directives/global_nav/app_switcher/__tests__/app_switcher.js
@@ -18,7 +18,7 @@ describe('appSwitcher directive', function () {
 
   function setup(href, links) {
     return ngMock.inject(function ($window, $rootScope, $compile, Private) {
-      let domLocation = Private(DomLocationProvider);
+      const domLocation = Private(DomLocationProvider);
 
       $rootScope.chrome = {
         getNavLinks: constant(cloneDeep(links)),
@@ -46,14 +46,14 @@ describe('appSwitcher directive', function () {
   }
 
   context('when one link is for the active app', function () {
-    let myLink = {
+    const myLink = {
       active: true,
       title: 'myLink',
       url: 'http://localhost:555/app/myApp',
       lastSubUrl: 'http://localhost:555/app/myApp#/lastSubUrl'
     };
 
-    let notMyLink = {
+    const notMyLink = {
       active: false,
       title: 'notMyLink',
       url: 'http://localhost:555/app/notMyApp',
@@ -63,27 +63,27 @@ describe('appSwitcher directive', function () {
     beforeEach(setup('http://localhost:5555/app/myApp/', [myLink, notMyLink]));
 
     it('links to the inactive apps base url', function () {
-      let $myLink = env.$el.findTestSubject('appLink').eq(0);
+      const $myLink = env.$el.findTestSubject('appLink').eq(0);
       expect($myLink.prop('href')).to.be(myLink.url);
       expect($myLink.prop('href')).to.not.be(myLink.lastSubUrl);
     });
 
     it('links to the inactive apps last sub url', function () {
-      let $notMyLink = env.$el.findTestSubject('appLink').eq(1);
+      const $notMyLink = env.$el.findTestSubject('appLink').eq(1);
       expect($notMyLink.prop('href')).to.be(notMyLink.lastSubUrl);
       expect($notMyLink.prop('href')).to.not.be(notMyLink.url);
     });
   });
 
   context('when none of the links are for the active app', function () {
-    let myLink = {
+    const myLink = {
       active: false,
       title: 'myLink',
       url: 'http://localhost:555/app/myApp',
       lastSubUrl: 'http://localhost:555/app/myApp#/lastSubUrl'
     };
 
-    let notMyLink = {
+    const notMyLink = {
       active: false,
       title: 'notMyLink',
       url: 'http://localhost:555/app/notMyApp',
@@ -93,9 +93,9 @@ describe('appSwitcher directive', function () {
     beforeEach(setup('http://localhost:5555/app/myApp/', [myLink, notMyLink]));
 
     it('links to the lastSubUrl for each', function () {
-      let $links = env.$el.findTestSubject('appLink');
-      let $myLink = $links.eq(0);
-      let $notMyLink = $links.eq(1);
+      const $links = env.$el.findTestSubject('appLink');
+      const $myLink = $links.eq(0);
+      const $notMyLink = $links.eq(1);
 
       expect($myLink.prop('href')).to.be(myLink.lastSubUrl);
       expect($myLink.prop('href')).to.not.be(myLink.url);
@@ -106,19 +106,19 @@ describe('appSwitcher directive', function () {
   });
 
   context('clicking a link with matching href but missing hash', function () {
-    let url = 'http://localhost:555/app/myApp?query=1';
+    const url = 'http://localhost:555/app/myApp?query=1';
     beforeEach(setup(url + '#/lastSubUrl', [
       { url: url }
     ]));
 
     it('just prevents propogation (no reload)', function () {
-      let event = new $.Event('click');
+      const event = new $.Event('click');
 
       expect(env.location.reload.callCount).to.be(0);
       expect(event.isDefaultPrevented()).to.be(false);
       expect(event.isPropagationStopped()).to.be(false);
 
-      let $link = env.$el.findTestSubject('appLink');
+      const $link = env.$el.findTestSubject('appLink');
       expect($link.prop('href')).to.be(url);
       $link.trigger(event);
 
@@ -129,19 +129,19 @@ describe('appSwitcher directive', function () {
   });
 
   context('clicking a link that matches entire url', function () {
-    let url = 'http://localhost:555/app/myApp#/lastSubUrl';
+    const url = 'http://localhost:555/app/myApp#/lastSubUrl';
     beforeEach(setup(url, [
       { url: url }
     ]));
 
     it('calls window.location.reload and prevents propogation', function () {
-      let event = new $.Event('click');
+      const event = new $.Event('click');
 
       expect(env.location.reload.callCount).to.be(0);
       expect(event.isDefaultPrevented()).to.be(false);
       expect(event.isPropagationStopped()).to.be(false);
 
-      let $link = env.$el.findTestSubject('appLink');
+      const $link = env.$el.findTestSubject('appLink');
       expect($link.prop('href')).to.be(env.currentHref);
       $link.trigger(event);
 
@@ -152,21 +152,21 @@ describe('appSwitcher directive', function () {
   });
 
   context('clicking a link with matching href but changed hash', function () {
-    let rootUrl = 'http://localhost:555/app/myApp?query=1';
-    let url = rootUrl + '#/lastSubUrl2';
+    const rootUrl = 'http://localhost:555/app/myApp?query=1';
+    const url = rootUrl + '#/lastSubUrl2';
 
     beforeEach(setup(url + '#/lastSubUrl', [
       { url: url }
     ]));
 
     it('calls window.location.reload and prevents propogation', function () {
-      let event = new $.Event('click');
+      const event = new $.Event('click');
 
       expect(env.location.reload.callCount).to.be(0);
       expect(event.isDefaultPrevented()).to.be(false);
       expect(event.isPropagationStopped()).to.be(false);
 
-      let $link = env.$el.findTestSubject('appLink');
+      const $link = env.$el.findTestSubject('appLink');
       expect($link.prop('href')).to.be(url);
       $link.trigger(event);
 
@@ -185,7 +185,7 @@ describe('appSwitcher directive', function () {
     ]));
 
     it('allows click through', function () {
-      let event = new $.Event('click');
+      const event = new $.Event('click');
 
       expect(env.location.reload.callCount).to.be(0);
       expect(event.isPropagationStopped()).to.be(false);
@@ -206,7 +206,7 @@ describe('appSwitcher directive', function () {
     ]));
 
     it('allows click through', function () {
-      let event = new $.Event('click');
+      const event = new $.Event('click');
 
       expect(env.location.reload.callCount).to.be(0);
       expect(event.isPropagationStopped()).to.be(false);
diff --git a/src/ui/public/chrome/directives/kbn_chrome.js b/src/ui/public/chrome/directives/kbn_chrome.js
index 3a839f2b9e6b3..9a8376c4fe63d 100644
--- a/src/ui/public/chrome/directives/kbn_chrome.js
+++ b/src/ui/public/chrome/directives/kbn_chrome.js
@@ -33,7 +33,7 @@ export default function (chrome, internals) {
 
         // listen for route changes, propogate to tabs
         const onRouteChange = function () {
-          let { href } = window.location;
+          const { href } = window.location;
           internals.trackPossibleSubUrl(href);
         };
 
diff --git a/src/ui/public/collapsible_sidebar/collapsible_sidebar.js b/src/ui/public/collapsible_sidebar/collapsible_sidebar.js
index d19a70af9643e..fb99712ac49f7 100644
--- a/src/ui/public/collapsible_sidebar/collapsible_sidebar.js
+++ b/src/ui/public/collapsible_sidebar/collapsible_sidebar.js
@@ -8,15 +8,15 @@ uiModules
 .get('kibana')
 .directive('collapsibleSidebar', function () {
   // simply a list of all of all of angulars .col-md-* classes except 12
-  let listOfWidthClasses = _.times(11, function (i) { return 'col-md-' + i; });
+  const listOfWidthClasses = _.times(11, function (i) { return 'col-md-' + i; });
 
   return {
     restrict: 'C',
     link: function ($scope, $elem) {
-      let $collapser = $('<div class="sidebar-collapser"><div class="chevron-cont"></div></div>');
-      let $siblings = $elem.siblings();
+      const $collapser = $('<div class="sidebar-collapser"><div class="chevron-cont"></div></div>');
+      const $siblings = $elem.siblings();
 
-      let siblingsClass = listOfWidthClasses.reduce(function (prev, className) {
+      const siblingsClass = listOfWidthClasses.reduce(function (prev, className) {
         if (prev) return prev;
         return $siblings.hasClass(className) && className;
       }, false);
diff --git a/src/ui/public/courier/_redirect_when_missing.js b/src/ui/public/courier/_redirect_when_missing.js
index b86c75cba4129..5388cb65a879f 100644
--- a/src/ui/public/courier/_redirect_when_missing.js
+++ b/src/ui/public/courier/_redirect_when_missing.js
@@ -1,9 +1,9 @@
 import errors from 'ui/errors';
 
 export default function RedirectWhenMissingFn($location, kbnUrl, Notifier, Promise) {
-  let SavedObjectNotFound = errors.SavedObjectNotFound;
+  const SavedObjectNotFound = errors.SavedObjectNotFound;
 
-  let notify = new Notifier();
+  const notify = new Notifier();
 
   /**
    * Creates an error handler that will redirect to a url when a SavedObjectNotFound
diff --git a/src/ui/public/courier/_request_queue.js b/src/ui/public/courier/_request_queue.js
index b6dba26b187f1..b52a8a2fb4be3 100644
--- a/src/ui/public/courier/_request_queue.js
+++ b/src/ui/public/courier/_request_queue.js
@@ -6,7 +6,7 @@ export default function PendingRequestList() {
    * they are processed by fetch.[sourceType]().
    * @type {Array}
    */
-  let queue = [];
+  const queue = [];
 
   queue.getInactive = function (/* strategies */) {
     return queue.get.apply(queue, arguments)
diff --git a/src/ui/public/courier/courier.js b/src/ui/public/courier/courier.js
index 4e09d24a8ef82..b489460f8501c 100644
--- a/src/ui/public/courier/courier.js
+++ b/src/ui/public/courier/courier.js
@@ -24,18 +24,18 @@ import RedirectWhenMissingProvider from './_redirect_when_missing';
 uiModules.get('kibana/courier')
 .service('courier', function ($rootScope, Private, Promise, indexPatterns) {
   function Courier() {
-    let self = this;
+    const self = this;
 
-    let DocSource = Private(DocSourceProvider);
-    let SearchSource = Private(SearchSourceProvider);
-    let searchStrategy = Private(SearchStrategyProvider);
+    const DocSource = Private(DocSourceProvider);
+    const SearchSource = Private(SearchSourceProvider);
+    const searchStrategy = Private(SearchStrategyProvider);
 
-    let requestQueue = Private(RequestQueueProvider);
-    let errorHandlers = Private(ErrorHandlersProvider);
+    const requestQueue = Private(RequestQueueProvider);
+    const errorHandlers = Private(ErrorHandlersProvider);
 
-    let fetch = Private(FetchProvider);
-    let docLooper = self.docLooper = Private(DocLooperProvider);
-    let searchLooper = self.searchLooper = Private(SearchLooperProvider);
+    const fetch = Private(FetchProvider);
+    const docLooper = self.docLooper = Private(DocLooperProvider);
+    const searchLooper = self.searchLooper = Private(SearchLooperProvider);
 
     // expose some internal modules
     self.setRootSearchSource = Private(RootSearchSourceProvider).set;
@@ -47,7 +47,7 @@ uiModules.get('kibana/courier')
     self.DocSource = DocSource;
     self.SearchSource = SearchSource;
 
-    let HastyRefresh = errors.HastyRefresh;
+    const HastyRefresh = errors.HastyRefresh;
 
     /**
      * update the time between automatic search requests
@@ -135,8 +135,8 @@ uiModules.get('kibana/courier')
 
     // Listen for refreshInterval changes
     $rootScope.$watchCollection('timefilter.refreshInterval', function () {
-      let refreshValue = _.get($rootScope, 'timefilter.refreshInterval.value');
-      let refreshPause = _.get($rootScope, 'timefilter.refreshInterval.pause');
+      const refreshValue = _.get($rootScope, 'timefilter.refreshInterval.value');
+      const refreshPause = _.get($rootScope, 'timefilter.refreshInterval.pause');
       if (_.isNumber(refreshValue) && !refreshPause) {
         self.fetchInterval(refreshValue);
       } else {
@@ -144,7 +144,7 @@ uiModules.get('kibana/courier')
       }
     });
 
-    let onFatalDefer = Promise.defer();
+    const onFatalDefer = Promise.defer();
     onFatalDefer.promise.then(self.close);
     Notifier.fatalCallbacks.push(onFatalDefer.resolve);
   }
diff --git a/src/ui/public/courier/data_source/__tests__/decorate_query.js b/src/ui/public/courier/data_source/__tests__/decorate_query.js
index adae8151b2dcb..b72146bf8e38e 100644
--- a/src/ui/public/courier/data_source/__tests__/decorate_query.js
+++ b/src/ui/public/courier/data_source/__tests__/decorate_query.js
@@ -18,7 +18,7 @@ describe('Query decorator', function () {
     function ($provide) {
       // Super simple config stub
       $provide.service('config', function () {
-        let keys = {};
+        const keys = {};
         return {
           get: function (key) { return keys[key]; },
           set: function (key, value) { keys[key] = value; }
diff --git a/src/ui/public/courier/data_source/__tests__/normalize_sort_request.js b/src/ui/public/courier/data_source/__tests__/normalize_sort_request.js
index 061e73e7adfe8..3ab6983a75254 100644
--- a/src/ui/public/courier/data_source/__tests__/normalize_sort_request.js
+++ b/src/ui/public/courier/data_source/__tests__/normalize_sort_request.js
@@ -24,8 +24,8 @@ describe('SearchSource#normalizeSortRequest', function () {
   }));
 
   it('should return an array', function () {
-    let sortable = { someField: 'desc'};
-    let result = normalizeSortRequest(sortable, indexPattern);
+    const sortable = { someField: 'desc'};
+    const result = normalizeSortRequest(sortable, indexPattern);
     expect(result).to.be.an(Array);
     expect(result).to.eql(normalizedSort);
     // ensure object passed in is not mutated
@@ -34,27 +34,27 @@ describe('SearchSource#normalizeSortRequest', function () {
   });
 
   it('should make plain string sort into the more verbose format', function () {
-    let result = normalizeSortRequest([{ someField: 'desc'}], indexPattern);
+    const result = normalizeSortRequest([{ someField: 'desc'}], indexPattern);
     expect(result).to.eql(normalizedSort);
   });
 
   it('should append default sort options', function () {
-    let sortState = [{
+    const sortState = [{
       someField: {
         order: 'desc',
         unmapped_type: 'boolean'
       }
     }];
-    let result = normalizeSortRequest(sortState, indexPattern);
+    const result = normalizeSortRequest(sortState, indexPattern);
     expect(result).to.eql(normalizedSort);
   });
 
   it('should enable script based sorting', function () {
-    let fieldName = 'script string';
-    let direction = 'desc';
-    let indexField = indexPattern.fields.byName[fieldName];
+    const fieldName = 'script string';
+    const direction = 'desc';
+    const indexField = indexPattern.fields.byName[fieldName];
 
-    let sortState = {};
+    const sortState = {};
     sortState[fieldName] = direction;
     normalizedSort = {
       _script: {
@@ -76,31 +76,31 @@ describe('SearchSource#normalizeSortRequest', function () {
   });
 
   it('should use script based sorting only on sortable types', function () {
-    let fieldName = 'script murmur3';
-    let direction = 'asc';
-    let indexField = indexPattern.fields.byName[fieldName];
+    const fieldName = 'script murmur3';
+    const direction = 'asc';
+    const indexField = indexPattern.fields.byName[fieldName];
 
-    let sortState = {};
+    const sortState = {};
     sortState[fieldName] = direction;
     normalizedSort = {};
     normalizedSort[fieldName] = {
       order: direction,
       unmapped_type: 'boolean'
     };
-    let result = normalizeSortRequest([sortState], indexPattern);
+    const result = normalizeSortRequest([sortState], indexPattern);
 
     expect(result).to.eql([normalizedSort]);
   });
 
   it('should remove unmapped_type parameter from _score sorting', function () {
-    let sortable = { _score: 'desc'};
-    let expected = [{
+    const sortable = { _score: 'desc'};
+    const expected = [{
       _score: {
         order: 'desc'
       }
     }];
 
-    let result = normalizeSortRequest(sortable, indexPattern);
+    const result = normalizeSortRequest(sortable, indexPattern);
     expect(_.isEqual(result, expected)).to.be.ok();
 
   });
diff --git a/src/ui/public/courier/data_source/_abstract.js b/src/ui/public/courier/data_source/_abstract.js
index 4829ef661944a..34680a2c5f679 100644
--- a/src/ui/public/courier/data_source/_abstract.js
+++ b/src/ui/public/courier/data_source/_abstract.js
@@ -9,12 +9,12 @@ import FetchProvider from '../fetch';
 import DecorateQueryProvider from './_decorate_query';
 
 export default function SourceAbstractFactory(Private, Promise, PromiseEmitter) {
-  let requestQueue = Private(RequestQueueProvider);
-  let errorHandlers = Private(ErrorHandlersProvider);
-  let courierFetch = Private(FetchProvider);
+  const requestQueue = Private(RequestQueueProvider);
+  const errorHandlers = Private(ErrorHandlersProvider);
+  const courierFetch = Private(FetchProvider);
 
   function SourceAbstract(initialState, strategy) {
-    let self = this;
+    const self = this;
     self._instanceid = _.uniqueId('data_source');
 
     self._state = (function () {
@@ -79,7 +79,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    *   string of the state value to set
    */
   SourceAbstract.prototype.set = function (state, val) {
-    let self = this;
+    const self = this;
 
     if (typeof state === 'string') {
       // the getter and setter methods check for undefined explicitly
@@ -125,7 +125,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @return {Promise}
    */
   SourceAbstract.prototype.onResults = function (handler) {
-    let self = this;
+    const self = this;
 
     return new PromiseEmitter(function (resolve, reject) {
       const defer = Promise.defer();
@@ -149,7 +149,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @return {Promise}
    */
   SourceAbstract.prototype.onError = function (handler) {
-    let self = this;
+    const self = this;
 
     return new PromiseEmitter(function (resolve, reject) {
       const defer = Promise.defer();
@@ -172,7 +172,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @async
    */
   SourceAbstract.prototype.fetch = function () {
-    let self = this;
+    const self = this;
     let req = _.first(self._myStartableQueued());
 
     if (!req) {
@@ -232,13 +232,13 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
    * @resolved {Object|null} - the flat state of the SourceAbstract
    */
   SourceAbstract.prototype._flatten = function () {
-    let type = this._getType();
+    const type = this._getType();
 
     // the merged state of this dataSource and it's ancestors
-    let flatState = {};
+    const flatState = {};
 
     // function used to write each property from each state object in the chain to flat state
-    let root = this;
+    const root = this;
 
     // start the chain at this source
     let current = this;
@@ -255,12 +255,12 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
           });
         }
 
-        let prom = root._mergeProp(flatState, value, key);
+        const prom = root._mergeProp(flatState, value, key);
         return Promise.is(prom) ? prom : null;
       }))
       .then(function () {
         // move to this sources parent
-        let parent = current.getParent();
+        const parent = current.getParent();
         // keep calling until we reach the top parent
         if (parent) {
           current = parent;
@@ -271,7 +271,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
     .then(function () {
       if (type === 'search') {
         // This is down here to prevent the circular dependency
-        let decorateQuery = Private(DecorateQueryProvider);
+        const decorateQuery = Private(DecorateQueryProvider);
 
         flatState.body = flatState.body || {};
 
@@ -283,7 +283,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
         }
 
         if (flatState.body.size > 0) {
-          let computedFields = flatState.index.getComputedFields();
+          const computedFields = flatState.index.getComputedFields();
           flatState.body.stored_fields = computedFields.storedFields;
           flatState.body._source = computedFields._source;
           flatState.body.script_fields = flatState.body.script_fields || {};
@@ -302,7 +302,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
          *                          through otherwise it will filter out
          * @returns {function}
          */
-        let filterNegate = function (reverse) {
+        const filterNegate = function (reverse) {
           return function (filter) {
             if (_.isUndefined(filter.meta) || _.isUndefined(filter.meta.negate)) return !reverse;
             return filter.meta && filter.meta.negate === reverse;
@@ -314,7 +314,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
         * @param  {Object} filter - The filter to translate
         * @return {Object} the query version of that filter
         */
-        let translateToQuery = function (filter) {
+        const translateToQuery = function (filter) {
           if (!filter) return;
 
           if (filter.query) {
@@ -329,7 +329,7 @@ export default function SourceAbstractFactory(Private, Promise, PromiseEmitter)
          * @param {object} filter The filter to clean
          * @returns {object}
          */
-        let cleanFilter = function (filter) {
+        const cleanFilter = function (filter) {
           return _.omit(filter, ['meta']);
         };
 
diff --git a/src/ui/public/courier/data_source/_decorate_query.js b/src/ui/public/courier/data_source/_decorate_query.js
index bb6fca29200b6..d0f009bf0a81c 100644
--- a/src/ui/public/courier/data_source/_decorate_query.js
+++ b/src/ui/public/courier/data_source/_decorate_query.js
@@ -7,7 +7,7 @@ export default function DecorateQuery(config) {
    * @returns {object}
    */
   return function (query) {
-    let queryOptions = config.get('query:queryString:options');
+    const queryOptions = config.get('query:queryString:options');
 
     if (_.has(query, 'query_string.query')) {
       _.extend(query.query_string, queryOptions);
diff --git a/src/ui/public/courier/data_source/_doc_send_to_es.js b/src/ui/public/courier/data_source/_doc_send_to_es.js
index 5cc07f9e0425e..8204918a30efa 100644
--- a/src/ui/public/courier/data_source/_doc_send_to_es.js
+++ b/src/ui/public/courier/data_source/_doc_send_to_es.js
@@ -5,8 +5,8 @@ import RequestQueueProvider from 'ui/courier/_request_queue';
 import FetchProvider from 'ui/courier/fetch/fetch';
 
 export default function (Promise, Private, es) {
-  let requestQueue = Private(RequestQueueProvider);
-  let courierFetch = Private(FetchProvider);
+  const requestQueue = Private(RequestQueueProvider);
+  const courierFetch = Private(FetchProvider);
 
   /**
    * Backend for doUpdate and doIndex
@@ -16,9 +16,9 @@ export default function (Promise, Private, es) {
    * @param  {String} body - HTTP request body
    */
   return function (method, validateVersion, body, ignore) {
-    let doc = this;
+    const doc = this;
     // straight assignment will causes undefined values
-    let params = _.pick(this._state, ['id', 'type', 'index']);
+    const params = _.pick(this._state, ['id', 'type', 'index']);
     params.body = body;
     params.ignore = ignore || [409];
 
@@ -51,13 +51,13 @@ export default function (Promise, Private, es) {
       // notify pending request for this same document that we have updates
       docFetchProm.then(function (fetchResp) {
         // use the key to compair sources
-        let key = doc._versionKey();
+        const key = doc._versionKey();
 
         // clear the queue and filter out the removed items, pushing the
         // unmatched ones back in.
-        let respondTo = requestQueue.splice(0).filter(function (req) {
-          let isDoc = req.source._getType() === 'doc';
-          let keyMatches = isDoc && req.source._versionKey() === key;
+        const respondTo = requestQueue.splice(0).filter(function (req) {
+          const isDoc = req.source._getType() === 'doc';
+          const keyMatches = isDoc && req.source._versionKey() === key;
 
           // put some request back into the queue
           if (!keyMatches) {
diff --git a/src/ui/public/courier/data_source/_normalize_sort_request.js b/src/ui/public/courier/data_source/_normalize_sort_request.js
index 7bab633bf1d4c..57465b67618d3 100644
--- a/src/ui/public/courier/data_source/_normalize_sort_request.js
+++ b/src/ui/public/courier/data_source/_normalize_sort_request.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 
 export default function normalizeSortRequest(config) {
-  let defaultSortOptions = config.get('sort:options');
+  const defaultSortOptions = config.get('sort:options');
 
   /**
    * Decorate queries with default parameters
@@ -9,7 +9,7 @@ export default function normalizeSortRequest(config) {
    * @returns {object}
    */
   return function (sortObject, indexPattern) {
-    let normalizedSort = [];
+    const normalizedSort = [];
 
     // [].concat({}) -> [{}], [].concat([{}]) -> [{}]
     return [].concat(sortObject).map(function (sortable) {
@@ -22,10 +22,10 @@ export default function normalizeSortRequest(config) {
     { someField: "desc" } into { someField: { "order": "desc"}}
   */
   function normalize(sortable, indexPattern) {
-    let normalized = {};
+    const normalized = {};
     let sortField = _.keys(sortable)[0];
     let sortValue = sortable[sortField];
-    let indexField = indexPattern.fields.byName[sortField];
+    const indexField = indexPattern.fields.byName[sortField];
 
     if (indexField && indexField.scripted && indexField.sortable) {
       let direction;
diff --git a/src/ui/public/courier/data_source/_root_search_source.js b/src/ui/public/courier/data_source/_root_search_source.js
index c3cb53ffb33c1..634360220326e 100644
--- a/src/ui/public/courier/data_source/_root_search_source.js
+++ b/src/ui/public/courier/data_source/_root_search_source.js
@@ -1,11 +1,11 @@
 import SearchSourceProvider from 'ui/courier/data_source/search_source';
 
 export default function RootSearchSource(Private, $rootScope, timefilter, Notifier) {
-  let SearchSource = Private(SearchSourceProvider);
+  const SearchSource = Private(SearchSourceProvider);
 
-  let notify = new Notifier({ location: 'Root Search Source' });
+  const notify = new Notifier({ location: 'Root Search Source' });
 
-  let globalSource = new SearchSource();
+  const globalSource = new SearchSource();
   globalSource.inherits(false); // this is the final source, it has no parents
   globalSource.filter(function (globalSource) {
     // dynamic time filter will be called in the _flatten phase of things
diff --git a/src/ui/public/courier/data_source/doc_source.js b/src/ui/public/courier/data_source/doc_source.js
index 67d6de7e9e6b5..2d447d825da68 100644
--- a/src/ui/public/courier/data_source/doc_source.js
+++ b/src/ui/public/courier/data_source/doc_source.js
@@ -9,10 +9,10 @@ import DocRequestProvider from '../fetch/request/doc';
 import DocStrategyProvider from '../fetch/strategy/doc';
 
 export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
-  let sendToEs = Private(DocSendToEsProvider);
-  let SourceAbstract = Private(AbstractDataSourceProvider);
-  let DocRequest = Private(DocRequestProvider);
-  let docStrategy = Private(DocStrategyProvider);
+  const sendToEs = Private(DocSendToEsProvider);
+  const SourceAbstract = Private(AbstractDataSourceProvider);
+  const DocRequest = Private(DocRequestProvider);
+  const docStrategy = Private(DocStrategyProvider);
 
   _.class(DocSource).inherits(SourceAbstract);
   function DocSource(initialState) {
@@ -99,7 +99,7 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
    * @return {string}
    */
   DocSource.prototype._versionKey = function () {
-    let state = this._state;
+    const state = this._state;
 
     if (!state.index || !state.type || !state.id) return;
     return 'DocVersion:' + (
@@ -125,10 +125,10 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
    * @return {[type]} [description]
    */
   DocSource.prototype._getStoredVersion = function () {
-    let key = this._versionKey();
+    const key = this._versionKey();
     if (!key) return;
 
-    let v = sessionStorage.get(key);
+    const v = sessionStorage.get(key);
     this._version = v ? _.parseInt(v) : void 0;
     return this._version;
   };
@@ -141,7 +141,7 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
   DocSource.prototype._storeVersion = function (version) {
     if (!version) return this._clearVersion();
 
-    let key = this._versionKey();
+    const key = this._versionKey();
     if (!key) return;
     this._version = version;
     sessionStorage.set(key, version);
@@ -151,7 +151,7 @@ export default function DocSourceFactory(Private, Promise, es, sessionStorage) {
    * Clears the stored version for a DocSource
    */
   DocSource.prototype._clearVersion = function () {
-    let key = this._versionKey();
+    const key = this._versionKey();
     if (!key) return;
     sessionStorage.remove(key);
   };
diff --git a/src/ui/public/courier/data_source/search_source.js b/src/ui/public/courier/data_source/search_source.js
index ef0fc31ab733c..7db35b4688931 100644
--- a/src/ui/public/courier/data_source/search_source.js
+++ b/src/ui/public/courier/data_source/search_source.js
@@ -8,11 +8,11 @@ import SegmentedRequestProvider from '../fetch/request/segmented';
 import SearchStrategyProvider from '../fetch/strategy/search';
 
 export default function SearchSourceFactory(Promise, Private) {
-  let SourceAbstract = Private(AbstractDataSourceProvider);
-  let SearchRequest = Private(SearchRequestProvider);
-  let SegmentedRequest = Private(SegmentedRequestProvider);
-  let searchStrategy = Private(SearchStrategyProvider);
-  let normalizeSortRequest = Private(NormalizeSortRequestProvider);
+  const SourceAbstract = Private(AbstractDataSourceProvider);
+  const SearchRequest = Private(SearchRequestProvider);
+  const SegmentedRequest = Private(SegmentedRequestProvider);
+  const searchStrategy = Private(SearchStrategyProvider);
+  const normalizeSortRequest = Private(NormalizeSortRequestProvider);
 
   _.class(SearchSource).inherits(SourceAbstract);
   function SearchSource(initialState) {
@@ -71,7 +71,7 @@ export default function SearchSourceFactory(Promise, Private) {
    * @return {undefined|searchSource}
    */
   SearchSource.prototype.getParent = function (onlyHardLinked) {
-    let self = this;
+    const self = this;
     if (self._parent === false) return;
     if (self._parent) return self._parent;
     return onlyHardLinked ? undefined : Private(rootSearchSource).get();
@@ -92,9 +92,9 @@ export default function SearchSourceFactory(Promise, Private) {
   };
 
   SearchSource.prototype.onBeginSegmentedFetch = function (initFunction) {
-    let self = this;
+    const self = this;
     return Promise.try(function addRequest() {
-      let req = new SegmentedRequest(self, Promise.defer(), initFunction);
+      const req = new SegmentedRequest(self, Promise.defer(), initFunction);
 
       // return promises created by the completion handler so that
       // errors will bubble properly
@@ -139,7 +139,7 @@ export default function SearchSourceFactory(Promise, Private) {
    */
   SearchSource.prototype._mergeProp = function (state, val, key) {
     if (typeof val === 'function') {
-      let source = this;
+      const source = this;
       return Promise.cast(val(this))
       .then(function (newVal) {
         return source._mergeProp(state, newVal, key);
diff --git a/src/ui/public/courier/looper/_looper.js b/src/ui/public/courier/looper/_looper.js
index 8ebf2df44d497..acb769c5f216b 100644
--- a/src/ui/public/courier/looper/_looper.js
+++ b/src/ui/public/courier/looper/_looper.js
@@ -4,7 +4,7 @@ import 'ui/promises';
 import Notifier from 'ui/notify/notifier';
 
 export default function LooperFactory($timeout, Promise) {
-  let notify = new Notifier();
+  const notify = new Notifier();
 
   function Looper(ms, fn) {
     this._fn = fn;
@@ -130,7 +130,7 @@ export default function LooperFactory($timeout, Promise) {
    * @return {undefined}
    */
   Looper.prototype._loopTheLoop = function () {
-    let self = this;
+    const self = this;
 
     if (self.active) {
       self.onHastyLoop();
diff --git a/src/ui/public/courier/looper/doc.js b/src/ui/public/courier/looper/doc.js
index e0f21394777c8..1e5363897c513 100644
--- a/src/ui/public/courier/looper/doc.js
+++ b/src/ui/public/courier/looper/doc.js
@@ -3,15 +3,15 @@ import LooperProvider from './_looper';
 import DocStrategyProvider from '../fetch/strategy/doc';
 
 export default function DocLooperService(Private) {
-  let fetch = Private(FetchProvider);
-  let Looper = Private(LooperProvider);
-  let DocStrategy = Private(DocStrategyProvider);
+  const fetch = Private(FetchProvider);
+  const Looper = Private(LooperProvider);
+  const DocStrategy = Private(DocStrategyProvider);
 
   /**
    * The Looper which will manage the doc fetch interval
    * @type {Looper}
    */
-  let docLooper = new Looper(1500, function () {
+  const docLooper = new Looper(1500, function () {
     fetch.fetchQueued(DocStrategy);
   });
 
diff --git a/src/ui/public/courier/looper/search.js b/src/ui/public/courier/looper/search.js
index ae6867f77d50d..8cd4c895a2972 100644
--- a/src/ui/public/courier/looper/search.js
+++ b/src/ui/public/courier/looper/search.js
@@ -4,18 +4,18 @@ import RequestQueueProvider from '../_request_queue';
 import LooperProvider from './_looper';
 
 export default function SearchLooperService(Private, Promise, Notifier, $rootScope) {
-  let fetch = Private(FetchProvider);
-  let searchStrategy = Private(SearchStrategyProvider);
-  let requestQueue = Private(RequestQueueProvider);
+  const fetch = Private(FetchProvider);
+  const searchStrategy = Private(SearchStrategyProvider);
+  const requestQueue = Private(RequestQueueProvider);
 
-  let Looper = Private(LooperProvider);
-  let notif = new Notifier({ location: 'Search Looper' });
+  const Looper = Private(LooperProvider);
+  const notif = new Notifier({ location: 'Search Looper' });
 
   /**
    * The Looper which will manage the doc fetch interval
    * @type {Looper}
    */
-  let searchLooper = new Looper(null, function () {
+  const searchLooper = new Looper(null, function () {
     $rootScope.$broadcast('courier:searchRefresh');
     return fetch.these(
       requestQueue.getInactive(searchStrategy)
diff --git a/src/ui/public/courier/saved_object/saved_object.js b/src/ui/public/courier/saved_object/saved_object.js
index 5c32ccac9064c..32d566e56b8e7 100644
--- a/src/ui/public/courier/saved_object/saved_object.js
+++ b/src/ui/public/courier/saved_object/saved_object.js
@@ -10,38 +10,38 @@ import SearchSourceProvider from '../data_source/search_source';
 
 export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notifier, safeConfirm, indexPatterns) {
 
-  let DocSource = Private(DocSourceProvider);
-  let SearchSource = Private(SearchSourceProvider);
-  let mappingSetup = Private(MappingSetupProvider);
+  const DocSource = Private(DocSourceProvider);
+  const SearchSource = Private(SearchSourceProvider);
+  const mappingSetup = Private(MappingSetupProvider);
 
   function SavedObject(config) {
     if (!_.isObject(config)) config = {};
 
     // save an easy reference to this
-    let self = this;
+    const self = this;
 
     /************
      * Initialize config vars
      ************/
     // the doc which is used to store this object
-    let docSource = new DocSource();
+    const docSource = new DocSource();
 
     // type name for this object, used as the ES-type
-    let type = config.type;
+    const type = config.type;
 
     // Create a notifier for sending alerts
-    let notify = new Notifier({
+    const notify = new Notifier({
       location: 'Saved ' + type
     });
 
     // mapping definition for the fields that this object will expose
-    let mapping = mappingSetup.expandShorthand(config.mapping);
+    const mapping = mappingSetup.expandShorthand(config.mapping);
 
     // default field values, assigned when the source is loaded
-    let defaults = config.defaults || {};
+    const defaults = config.defaults || {};
 
-    let afterESResp = config.afterESResp || _.noop;
-    let customInit = config.init || _.noop;
+    const afterESResp = config.afterESResp || _.noop;
+    const customInit = config.init || _.noop;
 
     // optional search source which this object configures
     self.searchSource = config.searchSource && new SearchSource();
@@ -113,7 +113,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
 
       if (resp.found != null && !resp.found) throw new errors.SavedObjectNotFound(type, self.id);
 
-      let meta = resp._source.kibanaSavedObjectMeta || {};
+      const meta = resp._source.kibanaSavedObjectMeta || {};
       delete resp._source.kibanaSavedObjectMeta;
 
       if (!config.indexPattern && self._source.indexPattern) {
@@ -158,8 +158,8 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
         state = {};
       }
 
-      let oldState = self.searchSource.toJSON();
-      let fnProps = _.transform(oldState, function (dynamic, val, name) {
+      const oldState = self.searchSource.toJSON();
+      const fnProps = _.transform(oldState, function (dynamic, val, name) {
         if (_.isFunction(val)) dynamic[name] = val;
       }, {});
 
@@ -200,7 +200,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
      * @return {Object}
      */
     self.serialize = function () {
-      let body = {};
+      const body = {};
 
       _.forOwn(mapping, function (fieldMapping, fieldName) {
         if (self[fieldName] != null) {
@@ -227,7 +227,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
      */
     self.save = function () {
 
-      let body = self.serialize();
+      const body = self.serialize();
 
       // Slugify the object id
       self.id = slugifyId(self.id);
@@ -240,7 +240,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
     };
 
     self.saveSource = function (source) {
-      let finish = function (id) {
+      const finish = function (id) {
         self.id = id;
         return es.indices.refresh({
           index: kbnIndex
@@ -255,7 +255,7 @@ export default function SavedObjectFactory(es, kbnIndex, Promise, Private, Notif
       .catch(function (err) {
         // record exists, confirm overwriting
         if (_.get(err, 'origError.status') === 409) {
-          let confirmMessage = 'Are you sure you want to overwrite ' + self.title + '?';
+          const confirmMessage = 'Are you sure you want to overwrite ' + self.title + '?';
 
           return safeConfirm(confirmMessage).then(
             function () {
diff --git a/src/ui/public/debounce/__tests__/debounce.js b/src/ui/public/debounce/__tests__/debounce.js
index 5208365c38a8f..9169c76a93568 100644
--- a/src/ui/public/debounce/__tests__/debounce.js
+++ b/src/ui/public/debounce/__tests__/debounce.js
@@ -27,14 +27,14 @@ describe('debounce service', function () {
 
   describe('API', function () {
     it('should have a cancel method', function () {
-      let bouncer = debounce(function () {}, 100);
+      const bouncer = debounce(function () {}, 100);
       expect(bouncer).to.have.property('cancel');
     });
   });
 
   describe('delayed execution', function () {
     it('should delay execution', function () {
-      let bouncer = debounce(spy, 100);
+      const bouncer = debounce(spy, 100);
       bouncer();
       expect(spy.callCount).to.be(0);
       $timeout.flush();
@@ -42,7 +42,7 @@ describe('debounce service', function () {
     });
 
     it('should fire on leading edge', function () {
-      let bouncer = debounce(spy, 100, { leading: true });
+      const bouncer = debounce(spy, 100, { leading: true });
       bouncer();
       expect(spy.callCount).to.be(1);
       $timeout.flush();
@@ -50,7 +50,7 @@ describe('debounce service', function () {
     });
 
     it('should only fire on leading edge', function () {
-      let bouncer = debounce(spy, 100, { leading: true, trailing: false });
+      const bouncer = debounce(spy, 100, { leading: true, trailing: false });
       bouncer();
       expect(spy.callCount).to.be(1);
       $timeout.flush();
@@ -58,8 +58,8 @@ describe('debounce service', function () {
     });
 
     it('should reset delayed execution', function (done) {
-      let cancelSpy = sinon.spy($timeout, 'cancel');
-      let bouncer = debounce(spy, 100);
+      const cancelSpy = sinon.spy($timeout, 'cancel');
+      const bouncer = debounce(spy, 100);
       bouncer();
       setTimeout(function () {
         bouncer();
@@ -74,8 +74,8 @@ describe('debounce service', function () {
 
   describe('cancel', function () {
     it('should cancel the $timeout', function () {
-      let cancelSpy = sinon.spy($timeout, 'cancel');
-      let bouncer = debounce(spy, 100);
+      const cancelSpy = sinon.spy($timeout, 'cancel');
+      const bouncer = debounce(spy, 100);
       bouncer();
       bouncer.cancel();
       expect(cancelSpy.callCount).to.be(1);
diff --git a/src/ui/public/debounce/debounce.js b/src/ui/public/debounce/debounce.js
index 7f8652f39d8f5..fc541e108c25e 100644
--- a/src/ui/public/debounce/debounce.js
+++ b/src/ui/public/debounce/debounce.js
@@ -3,7 +3,7 @@ import uiModules from 'ui/modules';
 // Debounce service, angularized version of lodash debounce
 // borrowed heavily from https://github.com/shahata/angular-debounce
 
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.service('debounce', ['$timeout', function ($timeout) {
   return function (func, wait, options) {
@@ -20,14 +20,14 @@ module.service('debounce', ['$timeout', function ($timeout) {
       self = this;
       args = arguments;
 
-      let later = function () {
+      const later = function () {
         timeout = null;
         if (!options.leading || options.trailing) {
           result = func.apply(self, args);
         }
       };
 
-      let callNow = options.leading && !timeout;
+      const callNow = options.leading && !timeout;
 
       if (timeout) {
         $timeout.cancel(timeout);
diff --git a/src/ui/public/directives/__tests__/auto_select_if_only_one.js b/src/ui/public/directives/__tests__/auto_select_if_only_one.js
index b414843698b9d..df5103f8d8a28 100644
--- a/src/ui/public/directives/__tests__/auto_select_if_only_one.js
+++ b/src/ui/public/directives/__tests__/auto_select_if_only_one.js
@@ -7,16 +7,16 @@ import 'ui/directives/auto_select_if_only_one';
 describe('Auto-select if only one directive', function () {
   let $compile;
   let $rootScope;
-  let zeroOptions = [];
-  let oneOption = [{label: 'foo'}];
-  let multiOptions = [{label: 'foo'}, {label: 'bar'}];
+  const zeroOptions = [];
+  const oneOption = [{label: 'foo'}];
+  const multiOptions = [{label: 'foo'}, {label: 'bar'}];
 
   beforeEach(ngMock.module('kibana'));
 
   beforeEach(ngMock.inject(function (_$compile_, _$rootScope_) {
     $compile = _$compile_;
     $rootScope = _$rootScope_;
-    let html = '<select ng-model="value" ng-options="option.name for option in options" auto-select-if-only-one="options"></select>';
+    const html = '<select ng-model="value" ng-options="option.name for option in options" auto-select-if-only-one="options"></select>';
     $compile(html)($rootScope);
     $rootScope.value = null;
   }));
@@ -41,7 +41,7 @@ describe('Auto-select if only one directive', function () {
 
   it('should still auto select if the collection contains 2 items but is filtered to 1', function () {
     $rootScope.options = multiOptions;
-    let html = '<select ng-model="value" ng-options="option.name for option in options | filter:{label:\'bar\'}" ' +
+    const html = '<select ng-model="value" ng-options="option.name for option in options | filter:{label:\'bar\'}" ' +
     'auto-select-if-only-one="options | filter:{label:\'bar\'}"></select>';
     $compile(html)($rootScope);
     $rootScope.value = null;
diff --git a/src/ui/public/directives/__tests__/confirm-click.js b/src/ui/public/directives/__tests__/confirm-click.js
index bdb7e7d62355e..8e0f2aefb3e3e 100644
--- a/src/ui/public/directives/__tests__/confirm-click.js
+++ b/src/ui/public/directives/__tests__/confirm-click.js
@@ -13,7 +13,7 @@ let $scope;
 
 let $elem;
 
-let init = function (text) {
+const init = function (text) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/directives/__tests__/css_truncate.js b/src/ui/public/directives/__tests__/css_truncate.js
index 535200bb0abc6..f8a008f13049f 100644
--- a/src/ui/public/directives/__tests__/css_truncate.js
+++ b/src/ui/public/directives/__tests__/css_truncate.js
@@ -10,7 +10,7 @@ let $scope;
 
 let $elem;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/directives/__tests__/fixed_scroll.js b/src/ui/public/directives/__tests__/fixed_scroll.js
index 7bcf4467ab740..b6488caf58a69 100644
--- a/src/ui/public/directives/__tests__/fixed_scroll.js
+++ b/src/ui/public/directives/__tests__/fixed_scroll.js
@@ -9,7 +9,7 @@ import Promise from 'bluebird';
 describe('FixedScroll directive', function () {
 
   let compile;
-  let trash = [];
+  const trash = [];
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function ($compile, $rootScope) {
@@ -19,7 +19,7 @@ describe('FixedScroll directive', function () {
 
       // since the directive works at the sibling level we create a
       // parent for everything to happen in
-      let $parent = $('<div>').css({
+      const $parent = $('<div>').css({
         position: 'fixed',
         top: 0,
         left: 0,
@@ -30,12 +30,12 @@ describe('FixedScroll directive', function () {
       $parent.appendTo(document.body);
       trash.push($parent);
 
-      let $el = $('<div fixed-scroll></div>').css({
+      const $el = $('<div fixed-scroll></div>').css({
         'overflow-x': 'auto',
         'width': $parent.width()
       }).appendTo($parent);
 
-      let $content = $('<div>').css({
+      const $content = $('<div>').css({
         width: $parent.width() * ratioX,
         height: $parent.height() * ratioY
       }).appendTo($el);
@@ -67,26 +67,26 @@ describe('FixedScroll directive', function () {
   });
 
   it('attaches a scroller below the element when the content is larger then the container', function () {
-    let els = compile(1.5);
+    const els = compile(1.5);
     expect(els.$scroller).to.have.length(1);
   });
 
   it('copies the width of the container', function () {
-    let els = compile(1.5);
+    const els = compile(1.5);
     expect(els.$scroller.width()).to.be(els.$container.width());
   });
 
   it('mimics the scrollWidth of the element', function () {
-    let els = compile(1.5);
+    const els = compile(1.5);
     expect(els.$scroller.prop('scrollWidth')).to.be(els.$container.prop('scrollWidth'));
   });
 
   describe('scroll event handling / tug of war prevention', function () {
     it('listens when needed, unlistens when not needed', function () {
-      let on = sinon.spy($.fn, 'on');
-      let off = sinon.spy($.fn, 'off');
+      const on = sinon.spy($.fn, 'on');
+      const off = sinon.spy($.fn, 'off');
 
-      let els = compile(1.5);
+      const els = compile(1.5);
       expect(on.callCount).to.be(2);
       checkThisVals('$.fn.on', on);
 
@@ -130,12 +130,12 @@ describe('FixedScroll directive', function () {
           expect(spy.callCount).to.be(2);
 
           // first call should read the scrollLeft from the $container
-          let firstCall = spy.getCall(0);
+          const firstCall = spy.getCall(0);
           expect(firstCall.thisValue.is($from)).to.be(true);
           expect(firstCall.args).to.eql([]);
 
           // second call should be setting the scrollLeft on the $scroller
-          let secondCall = spy.getCall(1);
+          const secondCall = spy.getCall(1);
           expect(secondCall.thisValue.is($to)).to.be(true);
           expect(secondCall.args).to.eql([firstCall.returnValue]);
         });
diff --git a/src/ui/public/directives/__tests__/input_focus.js b/src/ui/public/directives/__tests__/input_focus.js
index 5d30dbb52f0aa..e6d93ecef387e 100644
--- a/src/ui/public/directives/__tests__/input_focus.js
+++ b/src/ui/public/directives/__tests__/input_focus.js
@@ -12,7 +12,7 @@ describe('Input focus directive', function () {
   let $el;
   let selectedEl;
   let selectedText;
-  let inputValue = 'Input Text Value';
+  const inputValue = 'Input Text Value';
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function (_$compile_, _$rootScope_, _$timeout_) {
diff --git a/src/ui/public/directives/__tests__/input_whole_number.js b/src/ui/public/directives/__tests__/input_whole_number.js
index 0d97c28dfd767..e52e2aec1abb7 100644
--- a/src/ui/public/directives/__tests__/input_whole_number.js
+++ b/src/ui/public/directives/__tests__/input_whole_number.js
@@ -6,7 +6,7 @@ import 'ui/directives/input_whole_number';
 describe('Whole number input directive', function () {
   let $compile;
   let $rootScope;
-  let html = '<input type="text" ng-model="value" input-whole-number />';
+  const html = '<input type="text" ng-model="value" input-whole-number />';
 
   beforeEach(ngMock.module('kibana'));
 
@@ -16,7 +16,7 @@ describe('Whole number input directive', function () {
   }));
 
   it('should allow whole numbers', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = '123';
     $rootScope.$digest();
@@ -32,7 +32,7 @@ describe('Whole number input directive', function () {
   });
 
   it('should disallow numbers with decimals', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = '123.0';
     $rootScope.$digest();
diff --git a/src/ui/public/directives/__tests__/json_input.js b/src/ui/public/directives/__tests__/json_input.js
index b82de486c974c..9ee9cee7df1ad 100644
--- a/src/ui/public/directives/__tests__/json_input.js
+++ b/src/ui/public/directives/__tests__/json_input.js
@@ -7,7 +7,7 @@ import 'ui/directives/json_input';
 describe('JSON input validation', function () {
   let $compile;
   let $rootScope;
-  let html = '<input ng-model="value" json-input require-keys=true />';
+  const html = '<input ng-model="value" json-input require-keys=true />';
   let element;
 
   beforeEach(ngMock.module('kibana'));
@@ -28,8 +28,8 @@ describe('JSON input validation', function () {
   });
 
   it('should be able to not require keys', function () {
-    let html = '<input ng-model="value" json-input require-keys=false />';
-    let element = $compile(html)($rootScope);
+    const html = '<input ng-model="value" json-input require-keys=false />';
+    const element = $compile(html)($rootScope);
 
     element.val('{}');
     element.trigger('input');
diff --git a/src/ui/public/directives/__tests__/paginated_selectable_list.js b/src/ui/public/directives/__tests__/paginated_selectable_list.js
index a066d470b4497..30c5f906a5e37 100644
--- a/src/ui/public/directives/__tests__/paginated_selectable_list.js
+++ b/src/ui/public/directives/__tests__/paginated_selectable_list.js
@@ -3,7 +3,7 @@ import expect from 'expect.js';
 import ngMock from 'ng_mock';
 import _ from 'lodash';
 
-let objectList = [
+const objectList = [
   { title: 'apple' },
   { title: 'orange' },
   { title: 'coconut' },
@@ -11,7 +11,7 @@ let objectList = [
   { title: 'grapes' }
 ];
 
-let stringList = [
+const stringList = [
   'apple',
   'orange',
   'coconut',
@@ -19,18 +19,18 @@ let stringList = [
   'grapes'
 ];
 
-let lists = [objectList, stringList, []];
+const lists = [objectList, stringList, []];
 
 let $scope;
 let $element;
 let $isolatedScope;
 
 lists.forEach(function (list) {
-  let isArrayOfObjects = list.every((item) => {
+  const isArrayOfObjects = list.every((item) => {
     return _.isPlainObject(item);
   });
 
-  let init = function (arr, willFail) {
+  const init = function (arr, willFail) {
     // Load the application
     ngMock.module('kibana');
 
@@ -83,8 +83,8 @@ lists.forEach(function (list) {
       });
 
       it('should initially sort an array of objects in ascending order', function () {
-        let property = $isolatedScope.listProperty;
-        let sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
+        const property = $isolatedScope.listProperty;
+        const sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
 
         expect($isolatedScope.hits).to.be.an('array');
 
@@ -104,8 +104,8 @@ lists.forEach(function (list) {
       });
 
       it('should sort an array of objects in ascending order', function () {
-        let property = $isolatedScope.listProperty;
-        let sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
+        const property = $isolatedScope.listProperty;
+        const sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
 
         $isolatedScope.isAscending = false;
         $isolatedScope.sortHits(list);
@@ -122,8 +122,8 @@ lists.forEach(function (list) {
       });
 
       it('should sort an array of objects in descending order', function () {
-        let property = $isolatedScope.listProperty;
-        let reversedList = property ? _.sortBy(list, property).reverse() : _.sortBy(list).reverse();
+        const property = $isolatedScope.listProperty;
+        const reversedList = property ? _.sortBy(list, property).reverse() : _.sortBy(list).reverse();
 
         $isolatedScope.isAscending = true;
         $isolatedScope.sortHits(list);
@@ -146,8 +146,8 @@ lists.forEach(function (list) {
       });
 
       it('should return the result of the function its passed', function () {
-        let property = $isolatedScope.listProperty;
-        let sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
+        const property = $isolatedScope.listProperty;
+        const sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
 
         $isolatedScope.hits.forEach(function (hit, index) {
           if (property) {
@@ -165,8 +165,8 @@ lists.forEach(function (list) {
       });
 
       it('should return the result of the function its passed', function () {
-        let property = $isolatedScope.listProperty;
-        let sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
+        const property = $isolatedScope.listProperty;
+        const sortedList = property ? _.sortBy(list, property) : _.sortBy(list);
 
         $isolatedScope.userOnSelect = function (val) { return val; };
 
diff --git a/src/ui/public/directives/__tests__/parse_query.js b/src/ui/public/directives/__tests__/parse_query.js
index 6115bbdc20f35..fb2bc7bd13625 100644
--- a/src/ui/public/directives/__tests__/parse_query.js
+++ b/src/ui/public/directives/__tests__/parse_query.js
@@ -15,13 +15,13 @@ let $elemScope;
 let $elem;
 
 let cycleIndex = 0;
-let markup = '<input ng-model="mockModel" parse-query input-focus type="text">';
+const markup = '<input ng-model="mockModel" parse-query input-focus type="text">';
 let fromUser;
 import toUser from 'ui/parse_query/lib/to_user';
 import 'ui/parse_query';
 import ParseQueryLibFromUserProvider from 'ui/parse_query/lib/from_user';
 
-let init = function () {
+const init = function () {
   // Load the application
   ngMock.module('kibana');
 
@@ -41,7 +41,7 @@ let init = function () {
   });
 };
 
-let compile = function () {
+const compile = function () {
   $rootScope.mockModel = 'cycle' + cycleIndex++;
   $rootScope.mockQueryInput = undefined;
 
diff --git a/src/ui/public/directives/__tests__/timepicker.js b/src/ui/public/directives/__tests__/timepicker.js
index 46208d5e80cd1..f022f9d37158b 100644
--- a/src/ui/public/directives/__tests__/timepicker.js
+++ b/src/ui/public/directives/__tests__/timepicker.js
@@ -17,10 +17,10 @@ let $parentScope;
 let $scope;
 
 let $elem;
-let anchor = '2014-01-01T06:06:06.666Z';
+const anchor = '2014-01-01T06:06:06.666Z';
 let clock;
 
-let init = function () {
+const init = function () {
   // Load the application
   ngMock.module('kibana');
 
@@ -34,7 +34,7 @@ let init = function () {
     $parentScope = $rootScope;
 
     // Add some parameters to it
-    let timefilter = {
+    const timefilter = {
       time : {
         from: moment().subtract(15, 'minutes'),
         to: moment(),
@@ -174,7 +174,7 @@ describe('timepicker directive', function () {
       expect($elem.find('.kbn-timepicker-modes .active').text().trim()).to.be('quick');
 
       // Each of the 3 modes
-      let modes = ['absolute', 'relative', 'quick'];
+      const modes = ['absolute', 'relative', 'quick'];
       _.each(modes, function (mode) {
         $scope.setMode(mode);
         $scope.$digest();
@@ -215,7 +215,7 @@ describe('timepicker directive', function () {
     });
 
     it('has a preview of the "from" input', function (done) {
-      let preview = $elem.find('.kbn-timepicker-section span[ng-show="relative.preview"]');
+      const preview = $elem.find('.kbn-timepicker-section span[ng-show="relative.preview"]');
       expect(preview.text()).to.be(moment().subtract(15, 'minutes').format($scope.format));
       done();
     });
@@ -226,7 +226,7 @@ describe('timepicker directive', function () {
     });
 
     it('has a submit handler', function (done) {
-      let form = $elem.find('form[ng-submit="applyRelative()"]');
+      const form = $elem.find('form[ng-submit="applyRelative()"]');
       expect(form.length).to.be(1);
       done();
     });
@@ -247,7 +247,7 @@ describe('timepicker directive', function () {
     });
 
     it('has a dropdown bound to relative.unit that contains all of the intervals', function (done) {
-      let select = $elem.find('.kbn-timepicker-section select[ng-model="relative.unit"]');
+      const select = $elem.find('.kbn-timepicker-section select[ng-model="relative.unit"]');
       expect(select.length).to.be(1);
       expect(select.find('option').length).to.be(7);
 
@@ -259,7 +259,7 @@ describe('timepicker directive', function () {
     });
 
     it('has a checkbox that is checked when rounding is enabled', function (done) {
-      let checkbox = $elem.find('.kbn-timepicker-section input[ng-model="relative.round"]');
+      const checkbox = $elem.find('.kbn-timepicker-section input[ng-model="relative.round"]');
       expect(checkbox.length).to.be(1);
 
       // Rounding is disabled by default
@@ -335,8 +335,8 @@ describe('timepicker directive', function () {
     });
 
     it('updates the input fields when the scope variables are changed', function (done) {
-      let input = $elem.find('.kbn-timepicker-section input[ng-model="relative.count"]');
-      let select = $elem.find('.kbn-timepicker-section select[ng-model="relative.unit"]');
+      const input = $elem.find('.kbn-timepicker-section input[ng-model="relative.count"]');
+      const select = $elem.find('.kbn-timepicker-section select[ng-model="relative.unit"]');
 
       $scope.relative.count = 5;
       $scope.$digest();
diff --git a/src/ui/public/directives/__tests__/truncate.js b/src/ui/public/directives/__tests__/truncate.js
index 1ed5f4dba3aaf..9132c2bb3b7d1 100644
--- a/src/ui/public/directives/__tests__/truncate.js
+++ b/src/ui/public/directives/__tests__/truncate.js
@@ -11,7 +11,7 @@ let $scope;
 
 let $elem;
 
-let init = function (text) {
+const init = function (text) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/directives/__tests__/typeahead.js b/src/ui/public/directives/__tests__/typeahead.js
index 0c7424d356b3b..5e7ca60d896bb 100644
--- a/src/ui/public/directives/__tests__/typeahead.js
+++ b/src/ui/public/directives/__tests__/typeahead.js
@@ -7,8 +7,8 @@ import 'plugins/kibana/discover/index';
 
 // TODO: This should not be needed, timefilter is only included here, it should move
 
-let typeaheadHistoryCount = 10;
-let typeaheadName = 'unittest';
+const typeaheadHistoryCount = 10;
+const typeaheadName = 'unittest';
 let $parentScope;
 let $typeaheadScope;
 let $elem;
@@ -20,9 +20,9 @@ let markup = '<div class="typeahead" kbn-typeahead="' + typeaheadName + '">' +
   '<input type="text" placeholder="Filter..." class="form-control" ng-model="query" kbn-typeahead-input>' +
   '<kbn-typeahead-items></kbn-typeahead-items>' +
   '</div>';
-let typeaheadItems = ['abc', 'def', 'ghi'];
+const typeaheadItems = ['abc', 'def', 'ghi'];
 
-let init = function () {
+const init = function () {
   // Load the application
   ngMock.module('kibana');
 
@@ -64,7 +64,7 @@ let init = function () {
 describe('typeahead directive', function () {
   describe('typeahead requirements', function () {
     describe('missing input', function () {
-      let goodMarkup = markup;
+      const goodMarkup = markup;
 
       before(function () {
         markup = '<div class="typeahead" kbn-typeahead="' + typeaheadName + '">' +
@@ -99,7 +99,7 @@ describe('typeahead directive', function () {
       });
 
       it('should not save empty entries', function () {
-        let entries = typeaheadItems.slice(0);
+        const entries = typeaheadItems.slice(0);
         entries.push('', 'jkl');
         for (let i = 0; i < entries.length; i++) {
           $typeaheadScope.inputModel.$setViewValue(entries[i]);
@@ -129,9 +129,9 @@ describe('typeahead directive', function () {
       });
 
       it('should order filtered results', function () {
-        let entries = ['ac/dc', 'anthrax', 'abba', 'phantogram', 'skrillex'];
-        let allEntries = typeaheadItems.concat(entries);
-        let startMatches = allEntries.filter(function (item) {
+        const entries = ['ac/dc', 'anthrax', 'abba', 'phantogram', 'skrillex'];
+        const allEntries = typeaheadItems.concat(entries);
+        const startMatches = allEntries.filter(function (item) {
           return /^a/.test(item);
         });
         typeaheadCtrl.history.add.returns(allEntries);
@@ -144,7 +144,7 @@ describe('typeahead directive', function () {
         typeaheadCtrl.filterItemsByQuery('a');
 
         expect($typeaheadScope.filteredItems).to.contain('phantogram');
-        let nonStarterIndex = $typeaheadScope.filteredItems.indexOf('phantogram');
+        const nonStarterIndex = $typeaheadScope.filteredItems.indexOf('phantogram');
 
         startMatches.forEach(function (item) {
           expect($typeaheadScope.filteredItems).to.contain(item);
diff --git a/src/ui/public/directives/__tests__/validate_cidr_mask.js b/src/ui/public/directives/__tests__/validate_cidr_mask.js
index 702d983ab3b35..6fd8a623d13da 100644
--- a/src/ui/public/directives/__tests__/validate_cidr_mask.js
+++ b/src/ui/public/directives/__tests__/validate_cidr_mask.js
@@ -7,7 +7,7 @@ import 'ui/directives/validate_cidr_mask';
 describe('Validate CIDR mask directive', function () {
   let $compile;
   let $rootScope;
-  let html = '<input type="text" ng-model="value" validate-cidr-mask />';
+  const html = '<input type="text" ng-model="value" validate-cidr-mask />';
 
   beforeEach(ngMock.module('kibana'));
 
@@ -17,7 +17,7 @@ describe('Validate CIDR mask directive', function () {
   }));
 
   it('should allow empty input', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = '';
     $rootScope.$digest();
@@ -33,7 +33,7 @@ describe('Validate CIDR mask directive', function () {
   });
 
   it('should allow valid CIDR masks', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = '0.0.0.0/1';
     $rootScope.$digest();
@@ -53,7 +53,7 @@ describe('Validate CIDR mask directive', function () {
   });
 
   it('should disallow invalid CIDR masks', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = 'hello, world';
     $rootScope.$digest();
diff --git a/src/ui/public/directives/__tests__/validate_date_math.js b/src/ui/public/directives/__tests__/validate_date_math.js
index 02385b06a4940..869686b5fb1f3 100644
--- a/src/ui/public/directives/__tests__/validate_date_math.js
+++ b/src/ui/public/directives/__tests__/validate_date_math.js
@@ -7,7 +7,7 @@ import 'ui/directives/validate_date_math';
 describe('Validate date math directive', function () {
   let $compile;
   let $rootScope;
-  let html = '<input type="text" ng-model="value" validate-date-math />';
+  const html = '<input type="text" ng-model="value" validate-date-math />';
 
   beforeEach(ngMock.module('kibana'));
 
@@ -17,7 +17,7 @@ describe('Validate date math directive', function () {
   }));
 
   it('should allow valid date math', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = 'now';
     $rootScope.$digest();
@@ -41,7 +41,7 @@ describe('Validate date math directive', function () {
   });
 
   it('should disallow invalid date math', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = 'hello, world';
     $rootScope.$digest();
@@ -61,7 +61,7 @@ describe('Validate date math directive', function () {
   });
 
   it('should allow empty values', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = '';
     $rootScope.$digest();
diff --git a/src/ui/public/directives/__tests__/validate_index_name.js b/src/ui/public/directives/__tests__/validate_index_name.js
index 3deb454077e1e..4bd256ef15a86 100644
--- a/src/ui/public/directives/__tests__/validate_index_name.js
+++ b/src/ui/public/directives/__tests__/validate_index_name.js
@@ -8,8 +8,8 @@ import 'ui/directives/validate_index_name';
 describe('Validate index name directive', function () {
   let $compile;
   let $rootScope;
-  let noWildcardHtml = '<input type="text" ng-model="indexName" validate-index-name />';
-  let allowWildcardHtml = '<input type="text" ng-model="indexName" allow-wildcard validate-index-name />';
+  const noWildcardHtml = '<input type="text" ng-model="indexName" validate-index-name />';
+  const allowWildcardHtml = '<input type="text" ng-model="indexName" allow-wildcard validate-index-name />';
 
   beforeEach(ngMock.module('kibana'));
 
@@ -20,7 +20,7 @@ describe('Validate index name directive', function () {
 
   function checkPattern(input, html) {
     $rootScope.indexName = input;
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
     $rootScope.$digest();
     return element;
   }
@@ -57,7 +57,7 @@ describe('Validate index name directive', function () {
 
   badPatterns.forEach(function (pattern) {
     it('should not accept index pattern: ' + pattern, function () {
-      let element = checkPattern(pattern, noWildcardHtml);
+      const element = checkPattern(pattern, noWildcardHtml);
       expect(element.hasClass('ng-invalid')).to.be(true);
       expect(element.hasClass('ng-valid')).to.not.be(true);
     });
@@ -65,7 +65,7 @@ describe('Validate index name directive', function () {
 
   goodPatterns.forEach(function (pattern) {
     it('should accept index pattern: ' + pattern, function () {
-      let element = checkPattern(pattern, noWildcardHtml);
+      const element = checkPattern(pattern, noWildcardHtml);
       expect(element.hasClass('ng-invalid')).to.not.be(true);
       expect(element.hasClass('ng-valid')).to.be(true);
     });
@@ -73,7 +73,7 @@ describe('Validate index name directive', function () {
 
   it('should disallow wildcards by default', function () {
     wildcardPatterns.forEach(function (pattern) {
-      let element = checkPattern(pattern, noWildcardHtml);
+      const element = checkPattern(pattern, noWildcardHtml);
       expect(element.hasClass('ng-invalid')).to.be(true);
       expect(element.hasClass('ng-valid')).to.not.be(true);
     });
@@ -81,7 +81,7 @@ describe('Validate index name directive', function () {
 
   it('should allow wildcards if the allow-wildcard attribute is present', function () {
     wildcardPatterns.forEach(function (pattern) {
-      let element = checkPattern(pattern, allowWildcardHtml);
+      const element = checkPattern(pattern, allowWildcardHtml);
       expect(element.hasClass('ng-invalid')).to.not.be(true);
       expect(element.hasClass('ng-valid')).to.be(true);
     });
diff --git a/src/ui/public/directives/__tests__/validate_ip.js b/src/ui/public/directives/__tests__/validate_ip.js
index 9f5066f28f8cf..6e4e3c65cff64 100644
--- a/src/ui/public/directives/__tests__/validate_ip.js
+++ b/src/ui/public/directives/__tests__/validate_ip.js
@@ -7,7 +7,7 @@ import 'ui/directives/validate_ip';
 describe('Validate IP directive', function () {
   let $compile;
   let $rootScope;
-  let html = '<input type="text" ng-model="value" validate-ip />';
+  const html = '<input type="text" ng-model="value" validate-ip />';
 
   beforeEach(ngMock.module('kibana'));
 
@@ -17,7 +17,7 @@ describe('Validate IP directive', function () {
   }));
 
   it('should allow empty input', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = '';
     $rootScope.$digest();
@@ -33,7 +33,7 @@ describe('Validate IP directive', function () {
   });
 
   it('should allow valid IP addresses', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = '0.0.0.0';
     $rootScope.$digest();
@@ -53,7 +53,7 @@ describe('Validate IP directive', function () {
   });
 
   it('should disallow invalid IP addresses', function () {
-    let element = $compile(html)($rootScope);
+    const element = $compile(html)($rootScope);
 
     $rootScope.value = 'hello, world';
     $rootScope.$digest();
diff --git a/src/ui/public/directives/__tests__/validate_json.js b/src/ui/public/directives/__tests__/validate_json.js
index cf2616dc4baf1..69f4ea13d987e 100644
--- a/src/ui/public/directives/__tests__/validate_json.js
+++ b/src/ui/public/directives/__tests__/validate_json.js
@@ -8,23 +8,23 @@ import 'ui/directives/validate_json';
 let $parentScope;
 let $elemScope;
 let $elem;
-let mockScope = '';
+const mockScope = '';
 
-let input = {
+const input = {
   valid: '{ "test": "json input" }',
   invalid: 'strings are not json'
 };
 
-let markup = {
+const markup = {
   textarea: '<textarea ng-model="mockModel" validate-json></textarea>',
   input: '<input type="text" ng-model="mockModel" validate-json>'
 };
 
-let init = function (type) {
+const init = function (type) {
   // Load the application
   ngMock.module('kibana');
   type = type || 'input';
-  let elMarkup = markup[type];
+  const elMarkup = markup[type];
 
   // Create the scope
   ngMock.inject(function ($injector, $rootScope, $compile) {
@@ -39,7 +39,7 @@ let init = function (type) {
 };
 
 describe('validate-json directive', function () {
-  let checkValid = function (inputVal, className) {
+  const checkValid = function (inputVal, className) {
     $parentScope.mockModel = inputVal;
     $elem.scope().$digest();
     expect($elem.hasClass(className)).to.be(true);
diff --git a/src/ui/public/directives/auto_select_if_only_one.js b/src/ui/public/directives/auto_select_if_only_one.js
index 2fead2be3983c..0c77ed7d7150c 100644
--- a/src/ui/public/directives/auto_select_if_only_one.js
+++ b/src/ui/public/directives/auto_select_if_only_one.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('autoSelectIfOnlyOne', function ($parse) {
   return {
@@ -7,7 +7,7 @@ module.directive('autoSelectIfOnlyOne', function ($parse) {
     require: 'ngModel',
     link: function (scope, element, attributes, ngModelCtrl) {
       attributes.$observe('autoSelectIfOnlyOne', function (result) {
-        let options = $parse(result)(scope);
+        const options = $parse(result)(scope);
         if (options && options.length === 1) {
           ngModelCtrl.$setViewValue(options[0]);
           ngModelCtrl.$render();
diff --git a/src/ui/public/directives/bread_crumbs.js b/src/ui/public/directives/bread_crumbs.js
index b5a590a60b308..092ba98c519c0 100644
--- a/src/ui/public/directives/bread_crumbs.js
+++ b/src/ui/public/directives/bread_crumbs.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import chrome from 'ui/chrome/chrome';
 import breadCrumbsTemplate from 'ui/partials/bread_crumbs.html';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('breadCrumbs', function () {
   return {
diff --git a/src/ui/public/directives/click_focus.js b/src/ui/public/directives/click_focus.js
index 5a005676699c8..1c84249a131af 100644
--- a/src/ui/public/directives/click_focus.js
+++ b/src/ui/public/directives/click_focus.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import $ from 'jquery';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('clickFocus', function () {
   return {
@@ -11,7 +11,7 @@ module.directive('clickFocus', function () {
     restrict: 'A',
     link: function ($scope, $elem) {
       function handler() {
-        let focusElem = $.find('input[name=' + $scope.clickFocus + ']');
+        const focusElem = $.find('input[name=' + $scope.clickFocus + ']');
         if (focusElem[0]) focusElem[0].focus();
       }
 
diff --git a/src/ui/public/directives/confirm_click.js b/src/ui/public/directives/confirm_click.js
index 9c83e861ee292..fc7ae54a36499 100644
--- a/src/ui/public/directives/confirm_click.js
+++ b/src/ui/public/directives/confirm_click.js
@@ -6,9 +6,9 @@ uiModules
     restrict: 'A',
     link: function ($scope, $elem, attrs) {
       $elem.bind('click', function () {
-        let message = attrs.confirmation || 'Are you sure?';
+        const message = attrs.confirmation || 'Are you sure?';
         if (window.confirm(message)) { // eslint-disable-line no-alert
-          let action = attrs.confirmClick;
+          const action = attrs.confirmClick;
           if (action) {
             $scope.$apply($scope.$eval(action));
           }
diff --git a/src/ui/public/directives/css_truncate.js b/src/ui/public/directives/css_truncate.js
index b9541a814d2d2..718ddfdde7080 100644
--- a/src/ui/public/directives/css_truncate.js
+++ b/src/ui/public/directives/css_truncate.js
@@ -1,7 +1,7 @@
 import $ from 'jquery';
 import _ from 'lodash';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('cssTruncate', function ($timeout) {
   return {
diff --git a/src/ui/public/directives/field_name.js b/src/ui/public/directives/field_name.js
index ffeace0af0f7c..2a1837f610b2e 100644
--- a/src/ui/public/directives/field_name.js
+++ b/src/ui/public/directives/field_name.js
@@ -1,7 +1,7 @@
 import $ from 'jquery';
 import 'ui/filters/short_dots';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('fieldName', function ($compile, $rootScope, $filter) {
   return {
@@ -13,7 +13,7 @@ module.directive('fieldName', function ($compile, $rootScope, $filter) {
     },
     link: function ($scope, $el) {
 
-      let typeIcon = function (fieldType) {
+      const typeIcon = function (fieldType) {
         switch (fieldType) {
           case 'source':
             return '<i title="source" class="fa fa-file-text-o "></i>';
@@ -45,12 +45,12 @@ module.directive('fieldName', function ($compile, $rootScope, $filter) {
         'field.rowCount'
       ], function () {
 
-        let type = $scope.field ? $scope.field.type : $scope.fieldType;
-        let name = $scope.field ? $scope.field.name : $scope.fieldName;
-        let results = $scope.field ? !$scope.field.rowCount && !$scope.field.scripted : false;
-        let scripted = $scope.field ? $scope.field.scripted : false;
+        const type = $scope.field ? $scope.field.type : $scope.fieldType;
+        const name = $scope.field ? $scope.field.name : $scope.fieldName;
+        const results = $scope.field ? !$scope.field.rowCount && !$scope.field.scripted : false;
+        const scripted = $scope.field ? $scope.field.scripted : false;
 
-        let displayName = $filter('shortDots')(name);
+        const displayName = $filter('shortDots')(name);
 
         $el
           .attr('title', name)
diff --git a/src/ui/public/directives/file_upload.js b/src/ui/public/directives/file_upload.js
index 06c4752b456bf..80c11403b5759 100644
--- a/src/ui/public/directives/file_upload.js
+++ b/src/ui/public/directives/file_upload.js
@@ -1,9 +1,9 @@
 import _ from 'lodash';
 import $ from 'jquery';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
-let html = '<span class="dropzone" ng-transclude></span>';
+const html = '<span class="dropzone" ng-transclude></span>';
 
 module.directive('fileUpload', function () {
   return {
@@ -16,14 +16,14 @@ module.directive('fileUpload', function () {
     },
     template: html,
     link: function ($scope, $elem, attrs) {
-      let $button = $elem.find($scope.uploadSelector);
-      let $dropzone = $elem.find('.dropzone');
+      const $button = $elem.find($scope.uploadSelector);
+      const $dropzone = $elem.find('.dropzone');
 
       const handleFile = (file) => {
         if (_.isUndefined(file)) return;
 
         if (_.has(attrs, 'onRead')) {
-          let reader = new FileReader();
+          const reader = new FileReader();
           reader.onload = function (e) {
             $scope.$apply(function () {
               $scope.onRead({fileContents: e.target.result});
@@ -66,7 +66,7 @@ module.directive('fileUpload', function () {
         $elem.append($fileInput);
 
         $fileInput.on('change', function (e) {
-          let target = e.srcElement || e.target;
+          const target = e.srcElement || e.target;
           if (_.get(target, 'files.length')) {
             handleFile(target.files[0]);
           }
diff --git a/src/ui/public/directives/inequality.js b/src/ui/public/directives/inequality.js
index b6e2ed72b0688..44b0d0e977652 100644
--- a/src/ui/public/directives/inequality.js
+++ b/src/ui/public/directives/inequality.js
@@ -5,8 +5,8 @@ function makeDirectiveDef(id, compare) {
     return {
       require: 'ngModel',
       link: function ($scope, $el, $attr, ngModel) {
-        let getBound = function () { return $parse($attr[id])(); };
-        let defaultVal = {
+        const getBound = function () { return $parse($attr[id])(); };
+        const defaultVal = {
           'greaterThan': -Infinity,
           'lessThan': Infinity
         }[id];
@@ -19,8 +19,8 @@ function makeDirectiveDef(id, compare) {
         });
 
         function validate(val) {
-          let bound = !isNaN(getBound()) ? +getBound() : defaultVal;
-          let valid = !isNaN(bound) && !isNaN(val) && compare(val, bound);
+          const bound = !isNaN(getBound()) ? +getBound() : defaultVal;
+          const valid = !isNaN(bound) && !isNaN(val) && compare(val, bound);
           ngModel.$setValidity(id, valid);
           return val;
         }
diff --git a/src/ui/public/directives/infinite_scroll.js b/src/ui/public/directives/infinite_scroll.js
index db1f410f56ed0..4b888cbc60eac 100644
--- a/src/ui/public/directives/infinite_scroll.js
+++ b/src/ui/public/directives/infinite_scroll.js
@@ -1,6 +1,6 @@
 import $ from 'jquery';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('kbnInfiniteScroll', function () {
   return {
@@ -9,20 +9,20 @@ module.directive('kbnInfiniteScroll', function () {
       more: '='
     },
     link: function ($scope, $element, attrs) {
-      let $window = $(window);
+      const $window = $(window);
       let checkTimer;
 
       function onScroll() {
         if (!$scope.more) return;
 
-        let winHeight = $window.height();
-        let winBottom = winHeight + $window.scrollTop();
-        let elTop = $element.offset().top;
-        let remaining = elTop - winBottom;
+        const winHeight = $window.height();
+        const winBottom = winHeight + $window.scrollTop();
+        const elTop = $element.offset().top;
+        const remaining = elTop - winBottom;
 
         if (remaining <= winHeight * 0.50) {
           $scope[$scope.$$phase ? '$eval' : '$apply'](function () {
-            let more = $scope.more();
+            const more = $scope.more();
           });
         }
       }
diff --git a/src/ui/public/directives/input_datetime.js b/src/ui/public/directives/input_datetime.js
index 0559358e83093..3144182932371 100644
--- a/src/ui/public/directives/input_datetime.js
+++ b/src/ui/public/directives/input_datetime.js
@@ -2,7 +2,7 @@ import $ from 'jquery';
 import _ from 'lodash';
 import moment from 'moment';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('inputDatetime', function () {
   return {
@@ -10,18 +10,18 @@ module.directive('inputDatetime', function () {
     require: 'ngModel',
     link: function ($scope, $elem, attrs, ngModel) {
 
-      let format = 'YYYY-MM-DD HH:mm:ss.SSS';
+      const format = 'YYYY-MM-DD HH:mm:ss.SSS';
 
       $elem.after('<div class="input-datetime-format">' + format + '</div>');
 
       // What should I make with the input from the user?
-      let fromUser = function (text) {
-        let parsed = moment(text, format);
+      const fromUser = function (text) {
+        const parsed = moment(text, format);
         return parsed.isValid() ? parsed : undefined;
       };
 
       // How should I present the data back to the user in the input field?
-      let toUser = function (datetime) {
+      const toUser = function (datetime) {
         return moment(datetime).format(format);
       };
 
diff --git a/src/ui/public/directives/input_focus.js b/src/ui/public/directives/input_focus.js
index c6adccfd3e7b0..ce904b459e0f1 100644
--- a/src/ui/public/directives/input_focus.js
+++ b/src/ui/public/directives/input_focus.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('inputFocus', function ($timeout) {
   return {
diff --git a/src/ui/public/directives/input_whole_number.js b/src/ui/public/directives/input_whole_number.js
index 5a4f406ea5a9f..adbdd63c08634 100644
--- a/src/ui/public/directives/input_whole_number.js
+++ b/src/ui/public/directives/input_whole_number.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('inputWholeNumber', function () {
   return {
diff --git a/src/ui/public/directives/json_input.js b/src/ui/public/directives/json_input.js
index 640b5bd887906..35066233018b8 100644
--- a/src/ui/public/directives/json_input.js
+++ b/src/ui/public/directives/json_input.js
@@ -15,7 +15,7 @@ uiModules
       function fromJSON(value) {
         try {
           value = JSON.parse(value);
-          let validity = !scope.$eval(attrs.requireKeys) ? true : _.keys(value).length > 0;
+          const validity = !scope.$eval(attrs.requireKeys) ? true : _.keys(value).length > 0;
           ngModelCntrl.$setValidity('json', validity);
         } catch (e) {
           ngModelCntrl.$setValidity('json', false);
diff --git a/src/ui/public/directives/paginate.js b/src/ui/public/directives/paginate.js
index cf11e8ac6fd0d..cd44441ce4fdf 100644
--- a/src/ui/public/directives/paginate.js
+++ b/src/ui/public/directives/paginate.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import uiModules from 'ui/modules';
 import paginateControlsTemplate from 'ui/partials/paginate_controls.html';
 
-let PER_PAGE_DEFAULT = 10;
+const PER_PAGE_DEFAULT = 10;
 
 uiModules.get('kibana')
 .directive('paginate', function ($parse, $compile) {
@@ -22,7 +22,7 @@ uiModules.get('kibana')
           $el.prepend($compile('<paginate-controls class="paginate-top">')($scope));
         }
 
-        let paginate = $scope.paginate;
+        const paginate = $scope.paginate;
 
         // add some getters to the controller powered by attributes
         paginate.getList = $parse(attrs.list);
@@ -42,8 +42,8 @@ uiModules.get('kibana')
     },
     controllerAs: 'paginate',
     controller: function ($scope) {
-      let self = this;
-      let ALL = 0;
+      const self = this;
+      const ALL = 0;
 
       self.sizeOptions = [
         { title: '10', value: 10 },
@@ -62,8 +62,8 @@ uiModules.get('kibana')
           self.perPageProp,
           self.otherWidthGetter
         ], function (vals, oldVals) {
-          let intChanges = vals[0] !== oldVals[0];
-          let extChanges = vals[1] !== oldVals[1];
+          const intChanges = vals[0] !== oldVals[0];
+          const extChanges = vals[1] !== oldVals[1];
 
           if (intChanges) {
             if (!setPerPage(self.perPage)) {
@@ -102,14 +102,14 @@ uiModules.get('kibana')
         $scope.pages = [];
         if (!$scope.list) return;
 
-        let perPage = _.parseInt(self.perPage);
-        let count = perPage ? Math.ceil($scope.list.length / perPage) : 1;
+        const perPage = _.parseInt(self.perPage);
+        const count = perPage ? Math.ceil($scope.list.length / perPage) : 1;
 
         _.times(count, function (i) {
           let page;
 
           if (perPage) {
-            let start = perPage * i;
+            const start = perPage * i;
             page = $scope.list.slice(start, start + perPage);
           } else {
             page = $scope.list.slice(0);
@@ -144,7 +144,7 @@ uiModules.get('kibana')
 
         // setup the list of the other pages to link to
         $scope.otherPages = [];
-        let width = +self.otherWidthGetter($scope) || 5;
+        const width = +self.otherWidthGetter($scope) || 5;
         let left = page.i - Math.round((width - 1) / 2);
         let right = left + width - 1;
 
@@ -155,14 +155,14 @@ uiModules.get('kibana')
         }
 
         // shift extra right nums to left
-        let lastI = page.count - 1;
+        const lastI = page.count - 1;
         if (right > lastI) {
           right = lastI;
           left = right - width + 1;
         }
 
         for (let i = left; i <= right; i++) {
-          let other = $scope.pages[i];
+          const other = $scope.pages[i];
 
           if (!other) continue;
 
diff --git a/src/ui/public/directives/pretty_duration.js b/src/ui/public/directives/pretty_duration.js
index 4354f4d0ebaca..8d9653f80a348 100644
--- a/src/ui/public/directives/pretty_duration.js
+++ b/src/ui/public/directives/pretty_duration.js
@@ -4,7 +4,7 @@ import moment from 'moment';
 import 'ui/timepicker/quick_ranges';
 import 'ui/timepicker/time_units';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 
 module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
@@ -15,9 +15,9 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
       to: '='
     },
     link: function ($scope, $elem) {
-      let dateFormat = config.get('dateFormat');
+      const dateFormat = config.get('dateFormat');
 
-      let lookupByRange = {};
+      const lookupByRange = {};
       _.each(quickRanges, function (frame) {
         lookupByRange[frame.from + ' to ' + frame.to] = frame;
       });
@@ -26,13 +26,13 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
         let text;
         // If both parts are date math, try to look up a reasonable string
         if ($scope.from && $scope.to && !moment.isMoment($scope.from) && !moment.isMoment($scope.to)) {
-          let tryLookup = lookupByRange[$scope.from.toString() + ' to ' + $scope.to.toString()];
+          const tryLookup = lookupByRange[$scope.from.toString() + ' to ' + $scope.to.toString()];
           if (tryLookup) {
             $elem.text(tryLookup.display);
           } else {
-            let fromParts = $scope.from.toString().split('-');
+            const fromParts = $scope.from.toString().split('-');
             if ($scope.to.toString() === 'now' && fromParts[0] === 'now' && fromParts[1]) {
-              let rounded = fromParts[1].split('/');
+              const rounded = fromParts[1].split('/');
               text = 'Last ' + rounded[0];
               if (rounded[1]) {
                 text = text + ' rounded to the ' + timeUnits[rounded[1]];
@@ -49,7 +49,7 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
       };
 
       function cantLookup() {
-        let display = {};
+        const display = {};
         _.each(['from', 'to'], function (time) {
           if (moment.isMoment($scope[time])) {
             display[time] = $scope[time].format(dateFormat);
@@ -57,7 +57,7 @@ module.directive('prettyDuration', function (config, quickRanges, timeUnits) {
             if ($scope[time] === 'now') {
               display[time] = 'now';
             } else {
-              let tryParse = dateMath.parse($scope[time], time === 'to' ? true : false);
+              const tryParse = dateMath.parse($scope[time], time === 'to' ? true : false);
               display[time] = moment.isMoment(tryParse) ? '~ ' + tryParse.fromNow() : $scope[time];
             }
           }
diff --git a/src/ui/public/directives/rows.js b/src/ui/public/directives/rows.js
index 11f3ae3f2e969..c12ff304b5f7c 100644
--- a/src/ui/public/directives/rows.js
+++ b/src/ui/public/directives/rows.js
@@ -3,10 +3,10 @@ import _ from 'lodash';
 import AggConfigResult from 'ui/vis/agg_config_result';
 import FilterBarFilterBarClickHandlerProvider from 'ui/filter_bar/filter_bar_click_handler';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('kbnRows', function ($compile, $rootScope, getAppState, Private) {
-  let filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
+  const filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
   return {
     restrict: 'A',
     link: function ($scope, $el, attr) {
@@ -17,10 +17,10 @@ module.directive('kbnRows', function ($compile, $rootScope, getAppState, Private
         // access to it here. This may become a problem with the switch to BigNumber
         if (_.isNumeric(contents)) $cell.addClass('numeric-value');
 
-        let createAggConfigResultCell = function (aggConfigResult) {
-          let $cell = $(document.createElement('td'));
-          let $state = getAppState();
-          let clickHandler = filterBarClickHandler($state);
+        const createAggConfigResultCell = function (aggConfigResult) {
+          const $cell = $(document.createElement('td'));
+          const $state = getAppState();
+          const clickHandler = filterBarClickHandler($state);
           $cell.scope = $scope.$new();
           $cell.addClass('cell-hover');
           $cell.attr('ng-click', 'clickHandler($event)');
@@ -72,18 +72,18 @@ module.directive('kbnRows', function ($compile, $rootScope, getAppState, Private
         attr.kbnRowsMin
       ], function (vals) {
         let rows = vals[0];
-        let min = vals[1];
+        const min = vals[1];
 
         $el.empty();
 
         if (!_.isArray(rows)) rows = [];
-        let width = rows.reduce(maxRowSize, 0);
+        const width = rows.reduce(maxRowSize, 0);
 
         if (isFinite(min) && rows.length < min) {
           // clone the rows so that we can add elements to it without upsetting the original
           rows = _.clone(rows);
           // crate the empty row which will be pushed into the row list over and over
-          let emptyRow = new Array(width);
+          const emptyRow = new Array(width);
           // fill the empty row with values
           _.times(width, function (i) { emptyRow[i] = ''; });
           // push as many empty rows into the row array as needed
@@ -91,7 +91,7 @@ module.directive('kbnRows', function ($compile, $rootScope, getAppState, Private
         }
 
         rows.forEach(function (row) {
-          let $tr = $(document.createElement('tr')).appendTo($el);
+          const $tr = $(document.createElement('tr')).appendTo($el);
           row.forEach(function (cell) {
             addCell($tr, cell);
           });
diff --git a/src/ui/public/directives/saved_object_finder.js b/src/ui/public/directives/saved_object_finder.js
index d936f04342fd9..efa4f7ebf7fcc 100644
--- a/src/ui/public/directives/saved_object_finder.js
+++ b/src/ui/public/directives/saved_object_finder.js
@@ -4,11 +4,11 @@ import keymap from 'ui/utils/key_map';
 import SavedObjectsSavedObjectRegistryProvider from 'ui/saved_objects/saved_object_registry';
 import uiModules from 'ui/modules';
 import savedObjectFinderTemplate from 'ui/partials/saved_object_finder.html';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Private, config) {
 
-  let services = Private(SavedObjectsSavedObjectRegistryProvider).byLoaderPropertiesName;
+  const services = Private(SavedObjectsSavedObjectRegistryProvider).byLoaderPropertiesName;
 
   return {
     restrict: 'E',
@@ -25,16 +25,16 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
     template: savedObjectFinderTemplate,
     controllerAs: 'finder',
     controller: function ($scope, $element, $timeout) {
-      let self = this;
+      const self = this;
 
       // the text input element
-      let $input = $element.find('input[ng-model=filter]');
+      const $input = $element.find('input[ng-model=filter]');
 
       // The number of items to show in the list
       $scope.perPage = config.get('savedObjects:perPage');
 
       // the list that will hold the suggestions
-      let $list = $element.find('ul');
+      const $list = $element.find('ul');
 
       // the current filter string, used to check that returned results are still useful
       let currentFilter = $scope.filter;
@@ -97,7 +97,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
           $scope.userOnChoose(hit, $event);
         }
 
-        let url = self.makeUrl(hit);
+        const url = self.makeUrl(hit);
         if (!url || url === '#' || url.charAt(0) !== '#') return;
 
         $event.preventDefault();
@@ -135,7 +135,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
           case 'enter':
             if (self.hitCount !== 1) return;
 
-            let hit = self.hits[0];
+            const hit = self.hits[0];
             if (!hit) return;
 
             self.onChoose(hit, $event);
@@ -208,8 +208,8 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
           case 'enter':
             if (!self.selector.enabled) break;
 
-            let hitIndex = ((page.number - 1) * paginate.perPage) + self.selector.index;
-            let hit = self.hits[hitIndex];
+            const hitIndex = ((page.number - 1) * paginate.perPage) + self.selector.index;
+            const hit = self.hits[hitIndex];
             if (!hit) break;
 
             self.onChoose(hit, $event);
@@ -251,7 +251,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
         // but ensure that we don't search for the same
         // thing twice. This is called from multiple places
         // and needs to be smart about when it actually searches
-        let filter = currentFilter;
+        const filter = currentFilter;
         if (prevSearch === filter) return;
 
         prevSearch = filter;
@@ -267,7 +267,7 @@ module.directive('savedObjectFinder', function ($location, $injector, kbnUrl, Pr
       }
 
       function scrollIntoView($element, snapTop) {
-        let el = $element[0];
+        const el = $element[0];
 
         if (!el) return;
 
diff --git a/src/ui/public/directives/validate_date_math.js b/src/ui/public/directives/validate_date_math.js
index 23c601987e7cd..c433777bd8c1a 100644
--- a/src/ui/public/directives/validate_date_math.js
+++ b/src/ui/public/directives/validate_date_math.js
@@ -19,7 +19,7 @@ uiModules.get('kibana').directive('validateDateMath', function () {
           return null;
         }
 
-        let moment = dateMath.parse(input);
+        const moment = dateMath.parse(input);
         ngModel.$setValidity('validDateMath', moment != null && moment.isValid());
         return input;
       }
diff --git a/src/ui/public/directives/validate_index_name.js b/src/ui/public/directives/validate_index_name.js
index 10b51c4dfb8fb..8bc697ad7e575 100644
--- a/src/ui/public/directives/validate_index_name.js
+++ b/src/ui/public/directives/validate_index_name.js
@@ -15,10 +15,10 @@ uiModules
           illegalCharacters.push('*');
         }
 
-        let isValid = function (input) {
+        const isValid = function (input) {
           if (input == null || input === '' || input === '.' || input === '..') return false;
 
-          let match = _.find(illegalCharacters, function (character) {
+          const match = _.find(illegalCharacters, function (character) {
             return input.indexOf(character) >= 0;
           });
           return !match;
diff --git a/src/ui/public/directives/validate_json.js b/src/ui/public/directives/validate_json.js
index bf4df84f69da8..82253adb9159c 100644
--- a/src/ui/public/directives/validate_json.js
+++ b/src/ui/public/directives/validate_json.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import $ from 'jquery';
 import uiModules from 'ui/modules';
 
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.directive('validateJson', function ($compile) {
   return {
diff --git a/src/ui/public/doc_table/__tests__/doc_table.js b/src/ui/public/doc_table/__tests__/doc_table.js
index b5dc9c3dcbbf6..0bd7cf203e28d 100644
--- a/src/ui/public/doc_table/__tests__/doc_table.js
+++ b/src/ui/public/doc_table/__tests__/doc_table.js
@@ -23,7 +23,7 @@ let $timeout;
 
 let searchSource;
 
-let init = function ($elem, props) {
+const init = function ($elem, props) {
   ngMock.inject(function ($rootScope, $compile, _$timeout_) {
     $timeout = _$timeout_;
     $parentScope = $rootScope;
@@ -41,7 +41,7 @@ let init = function ($elem, props) {
   });
 };
 
-let destroy = function () {
+const destroy = function () {
   $scope.$destroy();
   $parentScope.$destroy();
 };
diff --git a/src/ui/public/doc_table/__tests__/lib/get_sort.js b/src/ui/public/doc_table/__tests__/lib/get_sort.js
index 3fc141bad8336..6a0aed4b8ba08 100644
--- a/src/ui/public/doc_table/__tests__/lib/get_sort.js
+++ b/src/ui/public/doc_table/__tests__/lib/get_sort.js
@@ -1,5 +1,5 @@
 import getSort from 'ui/doc_table/lib/get_sort';
-let defaultSort = {time: 'desc'};
+const defaultSort = {time: 'desc'};
 import expect from 'expect.js';
 import ngMock from 'ng_mock';
 import FixturesStubbedLogstashIndexPatternProvider from 'fixtures/stubbed_logstash_index_pattern';
diff --git a/src/ui/public/doc_table/__tests__/lib/rows_headers.js b/src/ui/public/doc_table/__tests__/lib/rows_headers.js
index f68527482c15e..36e9b786741b9 100644
--- a/src/ui/public/doc_table/__tests__/lib/rows_headers.js
+++ b/src/ui/public/doc_table/__tests__/lib/rows_headers.js
@@ -28,7 +28,7 @@ describe('Doc Table', function () {
   }));
 
   // Sets up the directive, take an element, and a list of properties to attach to the parent scope.
-  let init = function ($elem, props) {
+  const init = function ($elem, props) {
     ngMock.inject(function ($compile) {
       _.assign($parentScope, props);
       $compile($elem)($parentScope);
@@ -37,17 +37,17 @@ describe('Doc Table', function () {
     });
   };
 
-  let destroy = function () {
+  const destroy = function () {
     $scope.$destroy();
     $parentScope.$destroy();
   };
 
   // For testing column removing/adding for the header and the rows
   //
-  let columnTests = function (elemType, parentElem) {
+  const columnTests = function (elemType, parentElem) {
 
     it('should create a time column if the timefield is defined', function (done) {
-      let childElems = parentElem.find(elemType);
+      const childElems = parentElem.find(elemType);
       expect(childElems.length).to.be(2);
       done();
     });
@@ -79,7 +79,7 @@ describe('Doc Table', function () {
       delete parentElem.scope().indexPattern.timeFieldName;
       parentElem.scope().$digest();
 
-      let childElems = parentElem.find(elemType);
+      const childElems = parentElem.find(elemType);
       expect(childElems.length).to.be(1);
       done();
     });
@@ -89,7 +89,7 @@ describe('Doc Table', function () {
 
   describe('kbnTableHeader', function () {
 
-    let $elem = angular.element(
+    const $elem = angular.element(
       '<thead kbn-table-header columns="columns" index-pattern="indexPattern" sort="sort"></thead>'
     );
 
@@ -120,7 +120,7 @@ describe('Doc Table', function () {
       });
 
       it('should sort asc by default, then by desc if already sorting', function (done) {
-        let fields = ['bytes', '@timestamp'];
+        const fields = ['bytes', '@timestamp'];
 
         // Should not be sorted at first
         expect($scope.sorting).to.eql(undefined);
@@ -201,7 +201,7 @@ describe('Doc Table', function () {
   });
 
   describe('kbnTableRow', function () {
-    let $elem = angular.element(
+    const $elem = angular.element(
       '<tr kbn-table-row="row" ' +
       'columns="columns" ' +
       'sorting="sorting"' +
@@ -270,7 +270,7 @@ describe('Doc Table', function () {
 
   describe('kbnTableRow meta', function () {
 
-    let $elem = angular.element(
+    const $elem = angular.element(
         '<tr kbn-table-row="row" ' +
         'columns="columns" ' +
         'sorting="sorting"' +
@@ -281,7 +281,7 @@ describe('Doc Table', function () {
     let $details;
 
     beforeEach(function () {
-      let row = getFakeRow(0, mapping);
+      const row = getFakeRow(0, mapping);
       mapping._id = {indexed: true, type: 'string'};
       row._source._id = 'foo';
 
@@ -354,7 +354,7 @@ describe('Doc Table', function () {
       $root.columns.push('bytes');
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(4);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -367,7 +367,7 @@ describe('Doc Table', function () {
       $root.columns.push('request_body');
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(5);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -385,7 +385,7 @@ describe('Doc Table', function () {
       ];
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(6);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -400,7 +400,7 @@ describe('Doc Table', function () {
       _.pull($root.columns, '_source');
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(2);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -411,14 +411,14 @@ describe('Doc Table', function () {
       $root.columns.push('@timestamp');
       $root.$apply();
 
-      let $mid = $row.find('td');
+      const $mid = $row.find('td');
       expect($mid).to.have.length(4);
 
       $root.columns.pop();
       $root.columns.pop();
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(2);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -429,7 +429,7 @@ describe('Doc Table', function () {
       $root.columns.push('@timestamp', 'bytes');
       $root.$apply();
 
-      let $mid = $row.find('td');
+      const $mid = $row.find('td');
       expect($mid).to.have.length(5);
 
       $root.columns[0] = false; // _source
@@ -437,7 +437,7 @@ describe('Doc Table', function () {
       $root.columns = $root.columns.filter(Boolean);
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(3);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -451,7 +451,7 @@ describe('Doc Table', function () {
       $root.columns.push('request_body');
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(4);
       expect($after.eq(2).text().trim()).to.match(/^bytes_formatted/);
       expect($after.eq(3).text().trim()).to.match(/^bytes_formatted/);
@@ -461,13 +461,13 @@ describe('Doc Table', function () {
       $root.columns.push('bytes');
       $root.$apply();
 
-      let $mid = $row.find('td');
+      const $mid = $row.find('td');
       expect($mid).to.have.length(4);
 
       $root.columns.reverse();
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(4);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -479,13 +479,13 @@ describe('Doc Table', function () {
       $root.columns.push('bytes', 'response', '@timestamp');
       $root.$apply();
 
-      let $mid = $row.find('td');
+      const $mid = $row.find('td');
       expect($mid).to.have.length(6);
 
       $root.columns.reverse();
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(6);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
@@ -499,7 +499,7 @@ describe('Doc Table', function () {
       $root.columns.push('bytes', 'bytes', 'bytes');
       $root.$apply();
 
-      let $after = $row.find('td');
+      const $after = $row.find('td');
       expect($after).to.have.length(6);
       expect($after[0]).to.be($before[0]);
       expect($after[1]).to.be($before[1]);
diff --git a/src/ui/public/doc_table/components/table_header.js b/src/ui/public/doc_table/components/table_header.js
index b0c0d56644d68..68013a262d5b4 100644
--- a/src/ui/public/doc_table/components/table_header.js
+++ b/src/ui/public/doc_table/components/table_header.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import 'ui/filters/short_dots';
 import headerHtml from 'ui/doc_table/components/table_header.html';
 import uiModules from 'ui/modules';
-let module = uiModules.get('app/discover');
+const module = uiModules.get('app/discover');
 
 
 module.directive('kbnTableHeader', function (shortDotsFilter) {
@@ -16,9 +16,9 @@ module.directive('kbnTableHeader', function (shortDotsFilter) {
     template: headerHtml,
     controller: function ($scope) {
 
-      let sortableField = function (field) {
+      const sortableField = function (field) {
         if (!$scope.indexPattern) return;
-        let sortable = _.get($scope.indexPattern.fields.byName[field], 'sortable');
+        const sortable = _.get($scope.indexPattern.fields.byName[field], 'sortable');
         return sortable;
       };
 
@@ -34,8 +34,8 @@ module.directive('kbnTableHeader', function (shortDotsFilter) {
       $scope.headerClass = function (column) {
         if (!sortableField(column)) return;
 
-        let sorting = $scope.sorting;
-        let defaultClass = ['fa', 'fa-sort-up', 'table-header-sortchange'];
+        const sorting = $scope.sorting;
+        const defaultClass = ['fa', 'fa-sort-up', 'table-header-sortchange'];
 
         if (!sorting || column !== sorting[0]) return defaultClass;
         return ['fa', sorting[1] === 'asc' ? 'fa-sort-up' : 'fa-sort-down'];
@@ -62,7 +62,7 @@ module.directive('kbnTableHeader', function (shortDotsFilter) {
       $scope.sort = function (column) {
         if (!column || !sortableField(column)) return;
 
-        let sorting = $scope.sorting = $scope.sorting || [];
+        const sorting = $scope.sorting = $scope.sorting || [];
 
         let direction = sorting[1] || 'asc';
         if (sorting[0] !== column) {
diff --git a/src/ui/public/doc_table/components/table_row.js b/src/ui/public/doc_table/components/table_row.js
index 7dfdfe24fa69e..d6e5432ff353b 100644
--- a/src/ui/public/doc_table/components/table_row.js
+++ b/src/ui/public/doc_table/components/table_row.js
@@ -10,12 +10,12 @@ import noWhiteSpace from 'ui/utils/no_white_space';
 import openRowHtml from 'ui/doc_table/components/table_row/open.html';
 import detailsHtml from 'ui/doc_table/components/table_row/details.html';
 import uiModules from 'ui/modules';
-let module = uiModules.get('app/discover');
+const module = uiModules.get('app/discover');
 
 
 
 // guesstimate at the minimum number of chars wide cells in the table should be
-let MIN_LINE_LENGTH = 20;
+const MIN_LINE_LENGTH = 20;
 
 /**
  * kbnTableRow directive
@@ -26,8 +26,8 @@ let MIN_LINE_LENGTH = 20;
  * ```
  */
 module.directive('kbnTableRow', function ($compile) {
-  let cellTemplate = _.template(noWhiteSpace(require('ui/doc_table/components/table_row/cell.html')));
-  let truncateByHeightTemplate = _.template(noWhiteSpace(require('ui/partials/truncate_by_height.html')));
+  const cellTemplate = _.template(noWhiteSpace(require('ui/doc_table/components/table_row/cell.html')));
+  const truncateByHeightTemplate = _.template(noWhiteSpace(require('ui/partials/truncate_by_height.html')));
 
   return {
     restrict: 'A',
@@ -41,7 +41,7 @@ module.directive('kbnTableRow', function ($compile) {
       $el.after('<tr>');
       $el.empty();
 
-      let init = function () {
+      const init = function () {
         createSummaryRow($scope.row, $scope.row._id);
       };
 
@@ -53,7 +53,7 @@ module.directive('kbnTableRow', function ($compile) {
 
       // toggle display of the rows details, a full list of the fields from each row
       $scope.toggleRow = function () {
-        let $detailsTr = $el.next();
+        const $detailsTr = $el.next();
 
         $scope.open = !$scope.open;
 
@@ -90,10 +90,10 @@ module.directive('kbnTableRow', function ($compile) {
 
       // create a tr element that lists the value for each *column*
       function createSummaryRow(row) {
-        let indexPattern = $scope.indexPattern;
+        const indexPattern = $scope.indexPattern;
 
         // We just create a string here because its faster.
-        let newHtmls = [
+        const newHtmls = [
           openRowHtml
         ];
 
@@ -114,16 +114,16 @@ module.directive('kbnTableRow', function ($compile) {
 
         let $cells = $el.children();
         newHtmls.forEach(function (html, i) {
-          let $cell = $cells.eq(i);
+          const $cell = $cells.eq(i);
           if ($cell.data('discover:html') === html) return;
 
-          let reuse = _.find($cells.slice(i + 1), function (cell) {
+          const reuse = _.find($cells.slice(i + 1), function (cell) {
             return $.data(cell, 'discover:html') === html;
           });
 
-          let $target = reuse ? $(reuse).detach() : $(html);
+          const $target = reuse ? $(reuse).detach() : $(html);
           $target.data('discover:html', html);
-          let $before = $cells.eq(i - 1);
+          const $before = $cells.eq(i - 1);
           if ($before.size()) {
             $before.after($target);
           } else {
@@ -151,7 +151,7 @@ module.directive('kbnTableRow', function ($compile) {
        * Fill an element with the value of a field
        */
       function _displayField(row, fieldName, breakWords) {
-        let indexPattern = $scope.indexPattern;
+        const indexPattern = $scope.indexPattern;
         let text = indexPattern.formatField(row, fieldName);
 
         if (breakWords) {
diff --git a/src/ui/public/doc_table/doc_table.js b/src/ui/public/doc_table/doc_table.js
index db3148a831525..c54e78f54724c 100644
--- a/src/ui/public/doc_table/doc_table.js
+++ b/src/ui/public/doc_table/doc_table.js
@@ -25,15 +25,15 @@ uiModules.get('kibana')
       filter: '=?',
     },
     link: function ($scope) {
-      let notify = new Notifier();
+      const notify = new Notifier();
       $scope.limit = 50;
       $scope.persist = {
         sorting: $scope.sorting,
         columns: $scope.columns
       };
 
-      let prereq = (function () {
-        let fns = [];
+      const prereq = (function () {
+        const fns = [];
 
         return function register(fn) {
           fns.push(fn);
@@ -59,7 +59,7 @@ uiModules.get('kibana')
       $scope.$watch('columns', function (columns) {
         if (columns.length !== 0) return;
 
-        let $state = getAppState();
+        const $state = getAppState();
         $scope.columns.push('_source');
         if ($state) $state.replace();
       });
diff --git a/src/ui/public/doc_table/lib/get_sort.js b/src/ui/public/doc_table/lib/get_sort.js
index e9f99615b1fce..c0124132083c7 100644
--- a/src/ui/public/doc_table/lib/get_sort.js
+++ b/src/ui/public/doc_table/lib/get_sort.js
@@ -7,7 +7,7 @@ import _ from 'lodash';
  * @returns {object} a sort object suitable for returning to elasticsearch
  */
 function getSort(sort, indexPattern) {
-  let sortObj = {};
+  const sortObj = {};
   let field;
   let direction;
 
diff --git a/src/ui/public/doc_title/__tests__/doc_title.js b/src/ui/public/doc_title/__tests__/doc_title.js
index faf38f9521473..104b3032dcadf 100644
--- a/src/ui/public/doc_title/__tests__/doc_title.js
+++ b/src/ui/public/doc_title/__tests__/doc_title.js
@@ -6,7 +6,7 @@ import DocTitleProvider from 'ui/doc_title';
 
 describe('docTitle Service', function () {
   let initialDocTitle;
-  let MAIN_TITLE = 'Kibana 4';
+  const MAIN_TITLE = 'Kibana 4';
 
   let docTitle;
   let $rootScope;
@@ -36,9 +36,9 @@ describe('docTitle Service', function () {
 
   describe('setup', function () {
     it('resets the title when a route change begins', function () {
-      let spy = $rootScope.$on;
+      const spy = $rootScope.$on;
 
-      let found = spy.args.some(function (args) {
+      const found = spy.args.some(function (args) {
         return args[0] === '$routeChangeStart' && args[1] === docTitle.reset;
       });
 
diff --git a/src/ui/public/doc_title/doc_title.js b/src/ui/public/doc_title/doc_title.js
index 6f58e162ae5e5..32a1b4744d8d8 100644
--- a/src/ui/public/doc_title/doc_title.js
+++ b/src/ui/public/doc_title/doc_title.js
@@ -10,15 +10,15 @@ uiModules.get('kibana')
   $rootScope.$on('$routeChangeSuccess', docTitle.update);
 })
 .service('docTitle', function ($rootScope) {
-  let baseTitle = document.title;
-  let self = this;
+  const baseTitle = document.title;
+  const self = this;
 
   let lastChange;
 
   function render() {
     lastChange = lastChange || [];
 
-    let parts = [lastChange[0]];
+    const parts = [lastChange[0]];
 
     if (!lastChange[1]) parts.push(baseTitle);
 
diff --git a/src/ui/public/factories/__tests__/base_object.js b/src/ui/public/factories/__tests__/base_object.js
index 758ba090d679c..de7815130962e 100644
--- a/src/ui/public/factories/__tests__/base_object.js
+++ b/src/ui/public/factories/__tests__/base_object.js
@@ -16,31 +16,31 @@ describe('Base Object', function () {
   }));
 
   it('should take an inital set of values', function () {
-    let baseObject = new BaseObject({ message: 'test' });
+    const baseObject = new BaseObject({ message: 'test' });
     expect(baseObject).to.have.property('message', 'test');
   });
 
   it('should serialize _attributes to RISON', function () {
-    let baseObject = new BaseObject();
+    const baseObject = new BaseObject();
     baseObject.message = 'Testing... 1234';
-    let rison = baseObject.toRISON();
+    const rison = baseObject.toRISON();
     expect(rison).to.equal('(message:\'Testing... 1234\')');
   });
 
   it('should not serialize $$attributes to RISON', function () {
-    let baseObject = new BaseObject();
+    const baseObject = new BaseObject();
     baseObject.$$attributes = { foo: 'bar' };
     baseObject.message = 'Testing... 1234';
-    let rison = baseObject.toRISON();
+    const rison = baseObject.toRISON();
     expect(rison).to.equal('(message:\'Testing... 1234\')');
   });
 
   it('should serialize _attributes for JSON', function () {
-    let baseObject = new BaseObject();
+    const baseObject = new BaseObject();
     baseObject.message = 'Testing... 1234';
     baseObject._private = 'foo';
     baseObject.$private = 'stuff';
-    let json = JSON.stringify(baseObject);
+    const json = JSON.stringify(baseObject);
     expect(json).to.equal('{"message":"Testing... 1234"}');
   });
 
diff --git a/src/ui/public/factories/__tests__/events.js b/src/ui/public/factories/__tests__/events.js
index 659490bbbb126..974f07b922148 100644
--- a/src/ui/public/factories/__tests__/events.js
+++ b/src/ui/public/factories/__tests__/events.js
@@ -24,8 +24,8 @@ describe('Events', function () {
   }));
 
   it('should handle on events', function () {
-    let obj = new Events();
-    let prom = obj.on('test', function (message) {
+    const obj = new Events();
+    const prom = obj.on('test', function (message) {
       expect(message).to.equal('Hello World');
     });
 
@@ -39,9 +39,9 @@ describe('Events', function () {
     function MyEventedObject() {
       MyEventedObject.Super.call(this);
     }
-    let obj = new MyEventedObject();
+    const obj = new MyEventedObject();
 
-    let prom = obj.on('test', function (message) {
+    const prom = obj.on('test', function (message) {
       expect(message).to.equal('Hello World');
     });
 
@@ -51,7 +51,7 @@ describe('Events', function () {
   });
 
   it('should clear events when off is called', function () {
-    let obj = new Events();
+    const obj = new Events();
     obj.on('test', _.noop);
     expect(obj._listeners).to.have.property('test');
     expect(obj._listeners.test).to.have.length(1);
@@ -60,9 +60,9 @@ describe('Events', function () {
   });
 
   it('should clear a specific handler when off is called for an event', function () {
-    let obj = new Events();
-    let handler1 = sinon.stub();
-    let handler2 = sinon.stub();
+    const obj = new Events();
+    const handler1 = sinon.stub();
+    const handler2 = sinon.stub();
     obj.on('test', handler1);
     obj.on('test', handler2);
     expect(obj._listeners).to.have.property('test');
@@ -76,8 +76,8 @@ describe('Events', function () {
   });
 
   it('should clear a all handlers when off is called for an event', function () {
-    let obj = new Events();
-    let handler1 = sinon.stub();
+    const obj = new Events();
+    const handler1 = sinon.stub();
     obj.on('test', handler1);
     expect(obj._listeners).to.have.property('test');
     obj.off('test');
@@ -90,11 +90,11 @@ describe('Events', function () {
   });
 
   it('should handle mulitple identical emits in the same tick', function () {
-    let obj = new Events();
-    let handler1 = sinon.stub();
+    const obj = new Events();
+    const handler1 = sinon.stub();
 
     obj.on('test', handler1);
-    let emits = [
+    const emits = [
       obj.emit('test', 'one'),
       obj.emit('test', 'two'),
       obj.emit('test', 'three')
@@ -111,9 +111,9 @@ describe('Events', function () {
   });
 
   it('should handle emits from the handler', function () {
-    let obj = new Events();
-    let secondEmit = Promise.defer();
-    let handler1 = sinon.spy(function () {
+    const obj = new Events();
+    const secondEmit = Promise.defer();
+    const handler1 = sinon.spy(function () {
       if (handler1.calledTwice) {
         return;
       }
@@ -133,12 +133,12 @@ describe('Events', function () {
   });
 
   it('should only emit to handlers registered before emit is called', function () {
-    let obj = new Events();
-    let handler1 = sinon.stub();
-    let handler2 = sinon.stub();
+    const obj = new Events();
+    const handler1 = sinon.stub();
+    const handler2 = sinon.stub();
 
     obj.on('test', handler1);
-    let emits = [
+    const emits = [
       obj.emit('test', 'one'),
       obj.emit('test', 'two'),
       obj.emit('test', 'three')
@@ -150,7 +150,7 @@ describe('Events', function () {
 
       obj.on('test', handler2);
 
-      let emits2 = [
+      const emits2 = [
         obj.emit('test', 'four'),
         obj.emit('test', 'five'),
         obj.emit('test', 'six')
@@ -165,9 +165,9 @@ describe('Events', function () {
   });
 
   it('should pass multiple arguments from the emitter', function () {
-    let obj = new Events();
-    let handler = sinon.stub();
-    let payload = [
+    const obj = new Events();
+    const handler = sinon.stub();
+    const payload = [
       'one',
       { hello: 'tests' },
       null
@@ -183,8 +183,8 @@ describe('Events', function () {
   });
 
   it('should preserve the scope of the handler', function () {
-    let obj = new Events();
-    let expected = 'some value';
+    const obj = new Events();
+    const expected = 'some value';
     let testValue;
 
     function handler(arg1, arg2) {
@@ -200,9 +200,9 @@ describe('Events', function () {
   });
 
   it('should always emit in the same order', function () {
-    let handler = sinon.stub();
+    const handler = sinon.stub();
 
-    let obj = new Events();
+    const obj = new Events();
     obj.on('block', _.partial(handler, 'block'));
     obj.on('last', _.partial(handler, 'last'));
 
diff --git a/src/ui/public/fancy_forms/fancy_forms.js b/src/ui/public/fancy_forms/fancy_forms.js
index 457b1aa01442d..c96e520505678 100644
--- a/src/ui/public/fancy_forms/fancy_forms.js
+++ b/src/ui/public/fancy_forms/fancy_forms.js
@@ -12,16 +12,16 @@ uiModules
       // directive providers are arrays
       $delegate.forEach(function (directive) {
         // get metadata about all init fns
-        let chain = [directive.controller, DecorativeController].map(function (fn) {
-          let deps = $injector.annotate(fn);
+        const chain = [directive.controller, DecorativeController].map(function (fn) {
+          const deps = $injector.annotate(fn);
           return { deps: deps, fn: _.isArray(fn) ? _.last(fn) : fn };
         });
 
         // replace the controller with one that will setup the actual controller
         directive.controller = function stub() {
-          let allDeps = _.toArray(arguments);
+          const allDeps = _.toArray(arguments);
           return chain.reduce(function (controller, link, i) {
-            let deps = allDeps.splice(0, link.deps.length);
+            const deps = allDeps.splice(0, link.deps.length);
             return link.fn.apply(controller, deps) || controller;
           }, this);
         };
diff --git a/src/ui/public/fancy_forms/kbn_form_controller.js b/src/ui/public/fancy_forms/kbn_form_controller.js
index c4b9f4ef19717..ccb93885a349f 100644
--- a/src/ui/public/fancy_forms/kbn_form_controller.js
+++ b/src/ui/public/fancy_forms/kbn_form_controller.js
@@ -7,7 +7,7 @@ import _ from 'lodash';
  * @param {$scope} $scope
  */
 function KbnFormController($scope, $element) {
-  let self = this;
+  const self = this;
 
   self.errorCount = function (predicate) {
     return self.$$invalidModels().length;
@@ -21,14 +21,14 @@ function KbnFormController($scope, $element) {
   };
 
   self.describeErrors = function () {
-    let count = self.softErrorCount();
+    const count = self.softErrorCount();
     return count + ' Error' + (count === 1 ? '' : 's');
   };
 
   self.$$invalidModels = function (predicate) {
     predicate = _.callback(predicate);
 
-    let invalid = [];
+    const invalid = [];
 
     _.forOwn(self.$error, function collect(models) {
       if (!models) return;
diff --git a/src/ui/public/field_editor/__tests__/field_editor.js b/src/ui/public/field_editor/__tests__/field_editor.js
index 43b200fde76ca..528095b175b90 100644
--- a/src/ui/public/field_editor/__tests__/field_editor.js
+++ b/src/ui/public/field_editor/__tests__/field_editor.js
@@ -41,7 +41,7 @@ describe('FieldEditor directive', function () {
 
     it('exposes $scope.editor, a controller for the editor', function () {
       compile();
-      let editor = $scope.editor;
+      const editor = $scope.editor;
       expect(editor).to.be.an('object');
     });
   });
@@ -81,8 +81,8 @@ describe('FieldEditor directive', function () {
       });
 
       it('reflects changes to the index patterns field', function () {
-        let a = {};
-        let b = {};
+        const a = {};
+        const b = {};
 
         actual.script = a;
         expect(field.script).to.be(a);
@@ -92,7 +92,7 @@ describe('FieldEditor directive', function () {
       });
 
       it('is fully mutable, unlike the index patterns field', function () {
-        let origName = actual.name;
+        const origName = actual.name;
         actual.name = 'john';
         expect(actual.name).to.not.be('john');
         expect(actual.name).to.be(origName);
diff --git a/src/ui/public/field_editor/field_editor.js b/src/ui/public/field_editor/field_editor.js
index 57f9006dfa831..b7772485e0ff5 100644
--- a/src/ui/public/field_editor/field_editor.js
+++ b/src/ui/public/field_editor/field_editor.js
@@ -11,10 +11,10 @@ import fieldEditorTemplate from 'ui/field_editor/field_editor.html';
 uiModules
 .get('kibana', ['colorpicker.module'])
 .directive('fieldEditor', function (Private, $sce) {
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
-  let Field = Private(IndexPatternsFieldProvider);
-  let scriptingInfo = $sce.trustAsHtml(require('ui/field_editor/scripting_info.html'));
-  let scriptingWarning = $sce.trustAsHtml(require('ui/field_editor/scripting_warning.html'));
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
+  const Field = Private(IndexPatternsFieldProvider);
+  const scriptingInfo = $sce.trustAsHtml(require('ui/field_editor/scripting_info.html'));
+  const scriptingWarning = $sce.trustAsHtml(require('ui/field_editor/scripting_warning.html'));
 
   return {
     restrict: 'E',
@@ -25,8 +25,8 @@ uiModules
     },
     controllerAs: 'editor',
     controller: function ($scope, Notifier, kbnUrl) {
-      let self = this;
-      let notify = new Notifier({ location: 'Field Editor' });
+      const self = this;
+      const notify = new Notifier({ location: 'Field Editor' });
 
       self.scriptingInfo = scriptingInfo;
       self.scriptingWarning = scriptingWarning;
@@ -43,9 +43,9 @@ uiModules
 
       self.cancel = redirectAway;
       self.save = function () {
-        let indexPattern = self.indexPattern;
-        let fields = indexPattern.fields;
-        let field = self.field.toActualField();
+        const indexPattern = self.indexPattern;
+        const fields = indexPattern.fields;
+        const field = self.field.toActualField();
 
         fields.remove({ name: field.name });
         fields.push(field);
@@ -64,8 +64,8 @@ uiModules
       };
 
       self.delete = function () {
-        let indexPattern = self.indexPattern;
-        let field = self.field;
+        const indexPattern = self.indexPattern;
+        const field = self.field;
 
         indexPattern.fields.remove({ name: field.name });
         return indexPattern.save()
@@ -76,9 +76,9 @@ uiModules
       };
 
       $scope.$watch('editor.selectedFormatId', function (cur, prev) {
-        let format = self.field.format;
-        let changedFormat = cur !== prev;
-        let missingFormat = cur && (!format || format.type.id !== cur);
+        const format = self.field.format;
+        const changedFormat = cur !== prev;
+        const missingFormat = cur && (!format || format.type.id !== cur);
 
         if (!changedFormat || !missingFormat) return;
 
@@ -87,15 +87,15 @@ uiModules
       });
 
       $scope.$watch('editor.formatParams', function () {
-        let FieldFormat = getFieldFormatType();
+        const FieldFormat = getFieldFormatType();
         self.field.format = new FieldFormat(self.formatParams);
       }, true);
 
       // copy the defined properties of the field to a plain object
       // which is mutable, and capture the changed seperately.
       function shadowCopy(field) {
-        let changes = {};
-        let shadowProps = {
+        const changes = {};
+        const shadowProps = {
           toActualField: {
             // bring the shadow copy out of the shadows
             value: function toActualField() {
@@ -105,7 +105,7 @@ uiModules
         };
 
         Object.getOwnPropertyNames(field).forEach(function (prop) {
-          let desc = Object.getOwnPropertyDescriptor(field, prop);
+          const desc = Object.getOwnPropertyDescriptor(field, prop);
           shadowProps[prop] = {
             enumerable: desc.enumerable,
             get: function () {
@@ -130,7 +130,7 @@ uiModules
       }
 
       function initDefaultFormat() {
-        let def = Object.create(fieldFormats.getDefaultType(self.field.type));
+        const def = Object.create(fieldFormats.getDefaultType(self.field.type));
 
         // explicitly set to undefined to prevent inheritting the prototypes id
         def.id = undefined;
diff --git a/src/ui/public/field_format_editor/field_format_editor.js b/src/ui/public/field_format_editor/field_format_editor.js
index 962e1668397b0..85092ba9c6fe3 100644
--- a/src/ui/public/field_format_editor/field_format_editor.js
+++ b/src/ui/public/field_format_editor/field_format_editor.js
@@ -13,7 +13,7 @@ uiModules
     },
     controllerAs: 'editor',
     controller: function ($scope) {
-      let self = this;
+      const self = this;
 
       // bind the scope values to the controller, down with $scope.values
       $scope.editor = this;
@@ -40,7 +40,7 @@ uiModules
        * @return {undefined}
        */
       $scope.$watch('editor.field.format.type', function (FieldFormat) {
-        let opts = FieldFormat && FieldFormat.editor;
+        const opts = FieldFormat && FieldFormat.editor;
 
         if (!opts) {
           delete self.$$pseudoDirective;
@@ -67,14 +67,14 @@ uiModules
 
     },
     link: function ($scope, $el) {
-      let scopesToTeardown = [];
+      const scopesToTeardown = [];
 
       function setupScope(opts) {
         if (typeof opts !== 'object') {
           return scopesToTeardown[scopesToTeardown.push($scope.$new()) - 1];
         }
 
-        let isolate = scopesToTeardown[scopesToTeardown.push($scope.$new(true)) - 1];
+        const isolate = scopesToTeardown[scopesToTeardown.push($scope.$new(true)) - 1];
         _.forOwn(opts, function (from, to) {
           isolate.$bind(to, from, $scope);
         });
@@ -88,20 +88,20 @@ uiModules
         if (!directive) return $el.hide();
         else $el.show();
 
-        let askedForChild = !!directive.scope;
-        let reuseScope = !askedForChild && !directive.controller;
+        const askedForChild = !!directive.scope;
+        const reuseScope = !askedForChild && !directive.controller;
 
-        let $formatEditor = $('<div>').html(directive.template);
-        let $formatEditorScope = reuseScope ? $scope : setupScope(directive.scope);
+        const $formatEditor = $('<div>').html(directive.template);
+        const $formatEditorScope = reuseScope ? $scope : setupScope(directive.scope);
 
         if (directive.controller) {
           // bind the controller to the injected element
-          let cntrlAs = (directive.controllerAs ? ' as ' + directive.controllerAs : '');
+          const cntrlAs = (directive.controllerAs ? ' as ' + directive.controllerAs : '');
           $formatEditorScope.Controller = directive.controller;
           $formatEditor.attr('ng-controller', 'Controller' + cntrlAs);
         }
 
-        let attrs = {};
+        const attrs = {};
         let linkFns = directive.compile && directive.compile($el, attrs);
         if (!linkFns || _.isFunction(linkFns)) {
           linkFns = {
diff --git a/src/ui/public/field_format_editor/pattern/pattern.js b/src/ui/public/field_format_editor/pattern/pattern.js
index b13610f8c84f6..5e493c9a6807c 100644
--- a/src/ui/public/field_format_editor/pattern/pattern.js
+++ b/src/ui/public/field_format_editor/pattern/pattern.js
@@ -11,7 +11,7 @@ uiModules
     require: ['ngModel', '^fieldEditor'],
     scope: true,
     link: function ($scope, $el, attrs, cntrls) {
-      let ngModelCntrl = cntrls[0];
+      const ngModelCntrl = cntrls[0];
 
       $scope.$bind('inputs', attrs.inputs);
       $scope.$bind('placeholder', attrs.placeholder);
diff --git a/src/ui/public/field_format_editor/samples/samples.js b/src/ui/public/field_format_editor/samples/samples.js
index d391af37d1556..a0090bbc0e060 100644
--- a/src/ui/public/field_format_editor/samples/samples.js
+++ b/src/ui/public/field_format_editor/samples/samples.js
@@ -11,7 +11,7 @@ uiModules
     require: ['?^ngModel', '^fieldEditor'],
     scope: true,
     link: function ($scope, $el, attrs, cntrls) {
-      let ngModelCntrl = cntrls[0];
+      const ngModelCntrl = cntrls[0];
 
       $scope.samples = null;
       $scope.$bind('inputs', attrs.inputs);
@@ -21,14 +21,14 @@ uiModules
         '[]inputs'
       ], function () {
         $scope.samples = null;
-        let field = $scope.editor.field;
+        const field = $scope.editor.field;
 
         if (!field || !field.format) {
           return;
         }
 
         Promise.try(function () {
-          let converter = field.format.getConverterFor('html');
+          const converter = field.format.getConverterFor('html');
           $scope.samples = _.map($scope.inputs, function (input) {
             return [input, $sce.trustAsHtml(converter(input))];
           });
diff --git a/src/ui/public/filter_bar/__tests__/_add_filters.js b/src/ui/public/filter_bar/__tests__/_add_filters.js
index 8265d7f2705c4..5c280ce62818d 100644
--- a/src/ui/public/filter_bar/__tests__/_add_filters.js
+++ b/src/ui/public/filter_bar/__tests__/_add_filters.js
@@ -5,7 +5,7 @@ import ngMock from 'ng_mock';
 import MockState from 'fixtures/mock_state';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 describe('add filters', function () {
-  let storeNames = {
+  const storeNames = {
     app: 'appState',
     global: 'globalState'
   };
@@ -88,7 +88,7 @@ describe('add filters', function () {
     });
 
     it('should fire the update and fetch events', function () {
-      let emitSpy = sinon.spy(queryFilter, 'emit');
+      const emitSpy = sinon.spy(queryFilter, 'emit');
 
       // set up the watchers, add new filters, and crank the digest loop
       $rootScope.$digest();
@@ -109,7 +109,7 @@ describe('add filters', function () {
 
   describe('filter reconciliation', function () {
     it('should de-dupe appState filters being added', function () {
-      let newFilter = _.cloneDeep(filters[1]);
+      const newFilter = _.cloneDeep(filters[1]);
       appState.filters = filters;
       $rootScope.$digest();
       expect(appState.filters.length).to.be(3);
@@ -120,7 +120,7 @@ describe('add filters', function () {
     });
 
     it('should de-dupe globalState filters being added', function () {
-      let newFilter = _.cloneDeep(filters[1]);
+      const newFilter = _.cloneDeep(filters[1]);
       globalState.filters = filters;
       $rootScope.$digest();
       expect(globalState.filters.length).to.be(3);
@@ -131,16 +131,16 @@ describe('add filters', function () {
     });
 
     it('should mutate global filters on appState filter changes', function () {
-      let idx = 1;
+      const idx = 1;
       globalState.filters = filters;
       $rootScope.$digest();
 
-      let appFilter = _.cloneDeep(filters[idx]);
+      const appFilter = _.cloneDeep(filters[idx]);
       appFilter.meta.negate = true;
       queryFilter.addFilters(appFilter);
       $rootScope.$digest();
 
-      let res = queryFilter.getFilters();
+      const res = queryFilter.getFilters();
       expect(res).to.have.length(3);
       _.each(res, function (filter, i) {
         expect(filter.$state.store).to.be('globalState');
diff --git a/src/ui/public/filter_bar/__tests__/_get_filters.js b/src/ui/public/filter_bar/__tests__/_get_filters.js
index 6c1e3ee4b140a..d7df4834988ed 100644
--- a/src/ui/public/filter_bar/__tests__/_get_filters.js
+++ b/src/ui/public/filter_bar/__tests__/_get_filters.js
@@ -4,7 +4,7 @@ import expect from 'expect.js';
 import MockState from 'fixtures/mock_state';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 describe('get filters', function () {
-  let storeNames = {
+  const storeNames = {
     app: 'appState',
     global: 'globalState'
   };
@@ -55,7 +55,7 @@ describe('get filters', function () {
       expect(res[1]).to.eql(filters[0]);
 
       // should return updated version of filters
-      let newFilter = { query: { match: { '_type': { query: 'nginx', type: 'phrase' } } } };
+      const newFilter = { query: { match: { '_type': { query: 'nginx', type: 'phrase' } } } };
       appState.filters.push(newFilter);
 
       res = queryFilter.getFilters();
@@ -66,13 +66,13 @@ describe('get filters', function () {
       appState.filters = [filters[0]];
       globalState.filters = [filters[1]];
 
-      let res = queryFilter.getFilters();
+      const res = queryFilter.getFilters();
       expect(res[0].$state.store).to.be(storeNames.global);
       expect(res[1].$state.store).to.be(storeNames.app);
     });
 
     it('should return non-null filters from specific states', function () {
-      let states = [
+      const states = [
         [ globalState, queryFilter.getGlobalFilters ],
         [ appState, queryFilter.getAppFilters ],
       ];
@@ -81,14 +81,14 @@ describe('get filters', function () {
         state[0].filters = filters.slice(0);
         expect(state[0].filters).to.contain(null);
 
-        let res = state[1]();
+        const res = state[1]();
         expect(res.length).to.be(state[0].filters.length);
         expect(state[0].filters).to.not.contain(null);
       });
     });
 
     it('should replace the state, not save it', function () {
-      let states = [
+      const states = [
         [ globalState, queryFilter.getGlobalFilters ],
         [ appState, queryFilter.getAppFilters ],
       ];
@@ -102,7 +102,7 @@ describe('get filters', function () {
         expect(state[0].replace.called).to.be(false);
 
         state[0].filters = filters.slice(0);
-        let res = state[1]();
+        const res = state[1]();
         expect(state[0].save.called).to.be(false);
         expect(state[0].replace.called).to.be(true);
       });
@@ -131,11 +131,11 @@ describe('get filters', function () {
 
     it('should skip appState filters that match globalState filters', function () {
       globalState.filters = filters;
-      let appFilter = _.cloneDeep(filters[1]);
+      const appFilter = _.cloneDeep(filters[1]);
       appState.filters.push(appFilter);
 
       // global filters should be listed first
-      let res = queryFilter.getFilters();
+      const res = queryFilter.getFilters();
       expect(res).to.have.length(3);
       _.each(res, function (filter) {
         expect(filter.$state.store).to.be('globalState');
@@ -144,12 +144,12 @@ describe('get filters', function () {
 
     it('should append conflicting appState filters', function () {
       globalState.filters = filters;
-      let appFilter = _.cloneDeep(filters[1]);
+      const appFilter = _.cloneDeep(filters[1]);
       appFilter.meta.negate = true;
       appState.filters.push(appFilter);
 
       // global filters should be listed first
-      let res = queryFilter.getFilters();
+      const res = queryFilter.getFilters();
       expect(res).to.have.length(4);
       expect(res.filter(function (filter) {
         return filter.$state.store === storeNames.global;
@@ -162,7 +162,7 @@ describe('get filters', function () {
     it('should not affect disabled filters', function () {
       // test adding to globalState
       globalState.filters = _.map(filters, function (filter) {
-        let f = _.cloneDeep(filter);
+        const f = _.cloneDeep(filter);
         f.meta.disabled = true;
         return f;
       });
@@ -172,7 +172,7 @@ describe('get filters', function () {
 
       // test adding to appState
       globalState.filters = _.map(filters, function (filter) {
-        let f = _.cloneDeep(filter);
+        const f = _.cloneDeep(filter);
         f.meta.disabled = true;
         return f;
       });
diff --git a/src/ui/public/filter_bar/__tests__/_invert_filters.js b/src/ui/public/filter_bar/__tests__/_invert_filters.js
index 4148268eb4370..55760e869b1cf 100644
--- a/src/ui/public/filter_bar/__tests__/_invert_filters.js
+++ b/src/ui/public/filter_bar/__tests__/_invert_filters.js
@@ -5,7 +5,7 @@ import ngMock from 'ng_mock';
 import MockState from 'fixtures/mock_state';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 describe('invert filters', function () {
-  let storeNames = {
+  const storeNames = {
     app: 'appState',
     global: 'globalState'
   };
@@ -76,7 +76,7 @@ describe('invert filters', function () {
     });
 
     it('should fire the update and fetch events', function () {
-      let emitSpy = sinon.spy(queryFilter, 'emit');
+      const emitSpy = sinon.spy(queryFilter, 'emit');
       appState.filters = filters;
 
       // set up the watchers
diff --git a/src/ui/public/filter_bar/__tests__/_pin_filters.js b/src/ui/public/filter_bar/__tests__/_pin_filters.js
index 4f11d7dadcd20..c5c9da43800e5 100644
--- a/src/ui/public/filter_bar/__tests__/_pin_filters.js
+++ b/src/ui/public/filter_bar/__tests__/_pin_filters.js
@@ -5,7 +5,7 @@ import ngMock from 'ng_mock';
 import MockState from 'fixtures/mock_state';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 describe('pin filters', function () {
-  let storeNames = {
+  const storeNames = {
     app: 'appState',
     global: 'globalState'
   };
@@ -87,7 +87,7 @@ describe('pin filters', function () {
     });
 
     it('should move filter from appState to globalState', function () {
-      let filter = appState.filters[1];
+      const filter = appState.filters[1];
 
       queryFilter.pinFilter(filter);
       expect(globalState.filters).to.contain(filter);
@@ -96,7 +96,7 @@ describe('pin filters', function () {
     });
 
     it('should move filter from globalState to appState', function () {
-      let filter = globalState.filters[1];
+      const filter = globalState.filters[1];
 
       queryFilter.pinFilter(filter);
       expect(appState.filters).to.contain(filter);
@@ -106,8 +106,8 @@ describe('pin filters', function () {
 
 
     it('should only fire the update event', function () {
-      let emitSpy = sinon.spy(queryFilter, 'emit');
-      let filter = appState.filters[1];
+      const emitSpy = sinon.spy(queryFilter, 'emit');
+      const filter = appState.filters[1];
       $rootScope.$digest();
 
       queryFilter.pinFilter(filter);
@@ -131,8 +131,8 @@ describe('pin filters', function () {
     });
 
     it('should swap the filters in both states', function () {
-      let appSample = _.sample(appState.filters);
-      let globalSample = _.sample(globalState.filters);
+      const appSample = _.sample(appState.filters);
+      const globalSample = _.sample(globalState.filters);
 
       queryFilter.pinAll();
       expect(globalState.filters).to.have.length(5);
diff --git a/src/ui/public/filter_bar/__tests__/_remove_filters.js b/src/ui/public/filter_bar/__tests__/_remove_filters.js
index 1020536be3692..718aa30c11393 100644
--- a/src/ui/public/filter_bar/__tests__/_remove_filters.js
+++ b/src/ui/public/filter_bar/__tests__/_remove_filters.js
@@ -5,7 +5,7 @@ import ngMock from 'ng_mock';
 import MockState from 'fixtures/mock_state';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 describe('remove filters', function () {
-  let storeNames = {
+  const storeNames = {
     app: 'appState',
     global: 'globalState'
   };
@@ -69,7 +69,7 @@ describe('remove filters', function () {
     });
 
     it('should fire the update and fetch events', function () {
-      let emitSpy = sinon.spy(queryFilter, 'emit');
+      const emitSpy = sinon.spy(queryFilter, 'emit');
       appState.filters = filters;
       $rootScope.$digest();
 
@@ -116,7 +116,7 @@ describe('remove filters', function () {
       appState.filters.push(filters[2]);
       $rootScope.$digest();
 
-      let missedFilter = _.cloneDeep(filters[0]);
+      const missedFilter = _.cloneDeep(filters[0]);
       missedFilter.meta = {
         negate: !filters[0].meta.negate
       };
diff --git a/src/ui/public/filter_bar/__tests__/_toggle_filters.js b/src/ui/public/filter_bar/__tests__/_toggle_filters.js
index 4a7f4870654c2..9545c184ba79b 100644
--- a/src/ui/public/filter_bar/__tests__/_toggle_filters.js
+++ b/src/ui/public/filter_bar/__tests__/_toggle_filters.js
@@ -5,7 +5,7 @@ import sinon from 'auto-release-sinon';
 import MockState from 'fixtures/mock_state';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 describe('toggle filters', function () {
-  let storeNames = {
+  const storeNames = {
     app: 'appState',
     global: 'globalState'
   };
@@ -75,7 +75,7 @@ describe('toggle filters', function () {
     });
 
     it('should fire the update and fetch events', function () {
-      let emitSpy = sinon.spy(queryFilter, 'emit');
+      const emitSpy = sinon.spy(queryFilter, 'emit');
       appState.filters = filters;
       $rootScope.$digest();
 
diff --git a/src/ui/public/filter_bar/__tests__/_update_filters.js b/src/ui/public/filter_bar/__tests__/_update_filters.js
index efc813e2fff83..176f7543730db 100644
--- a/src/ui/public/filter_bar/__tests__/_update_filters.js
+++ b/src/ui/public/filter_bar/__tests__/_update_filters.js
@@ -5,7 +5,7 @@ import ngMock from 'ng_mock';
 import MockState from 'fixtures/mock_state';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 describe('update filters', function () {
-  let storeNames = {
+  const storeNames = {
     app: 'appState',
     global: 'globalState'
   };
diff --git a/src/ui/public/filter_bar/__tests__/filter_bar.js b/src/ui/public/filter_bar/__tests__/filter_bar.js
index 1228943506c6b..807765884ef22 100644
--- a/src/ui/public/filter_bar/__tests__/filter_bar.js
+++ b/src/ui/public/filter_bar/__tests__/filter_bar.js
@@ -43,7 +43,7 @@ describe('Filter Bar Directive', function () {
       Promise = $injector.get('Promise');
       mapFilter = Private(FilterBarLibMapFilterProvider);
 
-      let queryFilter = Private(FilterBarQueryFilterProvider);
+      const queryFilter = Private(FilterBarQueryFilterProvider);
       queryFilter.getFilters = function () {
         return appState.filters;
       };
@@ -52,7 +52,7 @@ describe('Filter Bar Directive', function () {
 
   describe('Element rendering', function () {
     beforeEach(function (done) {
-      let filters = [
+      const filters = [
         { meta: { index: 'logstash-*' }, query: { match: { '_type': { query: 'apache' } } } },
         { meta: { index: 'logstash-*' }, query: { match: { '_type': { query: 'nginx' } } } },
         { meta: { index: 'logstash-*' }, exists: { field: '@timestamp' } },
@@ -66,7 +66,7 @@ describe('Filter Bar Directive', function () {
         $scope = $el.isolateScope();
       });
 
-      let off = $rootScope.$on('filterbar:updated', function () {
+      const off = $rootScope.$on('filterbar:updated', function () {
         off();
         // force a nextTick so it continues *after* the $digest loop completes
         setTimeout(done, 0);
@@ -77,7 +77,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should render all the filters in state', function () {
-      let filters = $el.find('.filter');
+      const filters = $el.find('.filter');
       expect(filters).to.have.length(5);
       expect($(filters[0]).find('span')[0].innerHTML).to.equal('_type:');
       expect($(filters[0]).find('span')[1].innerHTML).to.equal('"apache"');
@@ -90,7 +90,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should be able to set an alias', function () {
-      let filter = $el.find('.filter')[4];
+      const filter = $el.find('.filter')[4];
       expect($(filter).find('span')[0].innerHTML).to.equal('foo');
     });
 
diff --git a/src/ui/public/filter_bar/__tests__/push_filter.js b/src/ui/public/filter_bar/__tests__/push_filter.js
index a38011f79b3c4..d166479a1c1dd 100644
--- a/src/ui/public/filter_bar/__tests__/push_filter.js
+++ b/src/ui/public/filter_bar/__tests__/push_filter.js
@@ -32,7 +32,7 @@ describe('Filter Bar pushFilter()', function () {
     }));
 
     it('should create the filters property it needed', function () {
-      let altState = {};
+      const altState = {};
       pushFilterFn(altState)(filter);
       expect(altState.filters).to.be.an(Array);
     });
diff --git a/src/ui/public/filter_bar/filter_bar.js b/src/ui/public/filter_bar/filter_bar.js
index d16b64332c0e9..068f7b92f3afe 100644
--- a/src/ui/public/filter_bar/filter_bar.js
+++ b/src/ui/public/filter_bar/filter_bar.js
@@ -11,17 +11,17 @@ import FilterBarLibFilterOutTimeBasedFilterProvider from 'ui/filter_bar/lib/filt
 import FilterBarLibChangeTimeFilterProvider from 'ui/filter_bar/lib/change_time_filter';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 
 module.directive('filterBar', function (Private, Promise, getAppState) {
-  let mapAndFlattenFilters = Private(FilterBarLibMapAndFlattenFiltersProvider);
-  let mapFlattenAndWrapFilters = Private(FilterBarLibMapFlattenAndWrapFiltersProvider);
-  let extractTimeFilter = Private(FilterBarLibExtractTimeFilterProvider);
-  let filterOutTimeBasedFilter = Private(FilterBarLibFilterOutTimeBasedFilterProvider);
-  let changeTimeFilter = Private(FilterBarLibChangeTimeFilterProvider);
-  let queryFilter = Private(FilterBarQueryFilterProvider);
-  let privateFilterFieldRegex = /(^\$|meta)/;
+  const mapAndFlattenFilters = Private(FilterBarLibMapAndFlattenFiltersProvider);
+  const mapFlattenAndWrapFilters = Private(FilterBarLibMapFlattenAndWrapFiltersProvider);
+  const extractTimeFilter = Private(FilterBarLibExtractTimeFilterProvider);
+  const filterOutTimeBasedFilter = Private(FilterBarLibFilterOutTimeBasedFilterProvider);
+  const changeTimeFilter = Private(FilterBarLibChangeTimeFilterProvider);
+  const queryFilter = Private(FilterBarQueryFilterProvider);
+  const privateFilterFieldRegex = /(^\$|meta)/;
 
   return {
     restrict: 'E',
@@ -48,7 +48,7 @@ module.directive('filterBar', function (Private, Promise, getAppState) {
 
       $scope.aceLoaded = function (editor) {
         editor.$blockScrolling = Infinity;
-        let session = editor.getSession();
+        const session = editor.getSession();
         session.setTabSize(2);
         session.setUseSoftTabs(true);
       };
@@ -141,7 +141,7 @@ module.directive('filterBar', function (Private, Promise, getAppState) {
       }
 
       function updateFilters() {
-        let filters = queryFilter.getFilters();
+        const filters = queryFilter.getFilters();
         mapAndFlattenFilters(filters).then(function (results) {
           // used to display the current filters in the state
           $scope.filters = _.sortBy(results, function (filter) {
diff --git a/src/ui/public/filter_bar/filter_bar_click_handler.js b/src/ui/public/filter_bar/filter_bar_click_handler.js
index 25c7ae1a3b1bf..ce4a67696cd2b 100644
--- a/src/ui/public/filter_bar/filter_bar_click_handler.js
+++ b/src/ui/public/filter_bar/filter_bar_click_handler.js
@@ -6,7 +6,7 @@ import findByParam from 'ui/utils/find_by_param';
 export default function (Notifier) {
   return function ($state) {
     return function (event, simulate) {
-      let notify = new Notifier({
+      const notify = new Notifier({
         location: 'Filter bar'
       });
       let aggConfigResult;
@@ -23,14 +23,14 @@ export default function (Notifier) {
       }
 
       if (aggConfigResult) {
-        let isLegendLabel = !!event.point.values;
+        const isLegendLabel = !!event.point.values;
         let aggBuckets = _.filter(aggConfigResult.getPath(), { type: 'bucket' });
 
         // For legend clicks, use the last bucket in the path
         if (isLegendLabel) {
           // series data has multiple values, use aggConfig on the first
           // hierarchical data values is an object with the addConfig
-          let aggConfig = findByParam(event.point.values, 'aggConfig');
+          const aggConfig = findByParam(event.point.values, 'aggConfig');
           aggBuckets = aggBuckets.filter((result) => result.aggConfig && result.aggConfig === aggConfig);
         }
 
diff --git a/src/ui/public/filter_bar/lib/__tests__/change_time_filter.js b/src/ui/public/filter_bar/lib/__tests__/change_time_filter.js
index cd596f04f4188..a33a92f0a4bf9 100644
--- a/src/ui/public/filter_bar/lib/__tests__/change_time_filter.js
+++ b/src/ui/public/filter_bar/lib/__tests__/change_time_filter.js
@@ -18,7 +18,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should change the timefilter to match the range gt/lt', function () {
-      let filter = { range: { '@timestamp': { gt: 1388559600000, lt: 1388646000000 } } };
+      const filter = { range: { '@timestamp': { gt: 1388559600000, lt: 1388646000000 } } };
       changeTimeFilter(filter);
       expect(timefilter.time.mode).to.be('absolute');
       expect(moment.isMoment(timefilter.time.to)).to.be(true);
@@ -28,7 +28,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should change the timefilter to match the range gte/lte', function () {
-      let filter = { range: { '@timestamp': { gte: 1388559600000, lte: 1388646000000 } } };
+      const filter = { range: { '@timestamp': { gte: 1388559600000, lte: 1388646000000 } } };
       changeTimeFilter(filter);
       expect(timefilter.time.mode).to.be('absolute');
       expect(moment.isMoment(timefilter.time.to)).to.be(true);
diff --git a/src/ui/public/filter_bar/lib/__tests__/dedup_filters.js b/src/ui/public/filter_bar/lib/__tests__/dedup_filters.js
index fc953a1b34049..e09308fa0f402 100644
--- a/src/ui/public/filter_bar/lib/__tests__/dedup_filters.js
+++ b/src/ui/public/filter_bar/lib/__tests__/dedup_filters.js
@@ -4,43 +4,43 @@ describe('Filter Bar Directive', function () {
   describe('dedupFilters(existing, filters)', function () {
 
     it('should return only filters which are not in the existing', function () {
-      let existing = [
+      const existing = [
         { range: { bytes: { from: 0, to: 1024 } } },
         { query: { match: { _term: { query: 'apache', type: 'phrase' } } } }
       ];
-      let filters = [
+      const filters = [
         { range: { bytes: { from: 1024, to: 2048 } } },
         { query: { match: { _term: { query: 'apache', type: 'phrase' } } } }
       ];
-      let results = dedupFilters(existing, filters);
+      const results = dedupFilters(existing, filters);
       expect(results).to.contain(filters[0]);
       expect(results).to.not.contain(filters[1]);
     });
 
     it('should ignore the disabed attribute when comparing ', function () {
-      let existing = [
+      const existing = [
         { range: { bytes: { from: 0, to: 1024 } } },
         { meta: { disabled: true }, query: { match: { _term: { query: 'apache', type: 'phrase' } } } }
       ];
-      let filters = [
+      const filters = [
         { range: { bytes: { from: 1024, to: 2048 } } },
         { query: { match: { _term: { query: 'apache', type: 'phrase' } } } }
       ];
-      let results = dedupFilters(existing, filters);
+      const results = dedupFilters(existing, filters);
       expect(results).to.contain(filters[0]);
       expect(results).to.not.contain(filters[1]);
     });
 
     it('should ignore $state attribute', function () {
-      let existing = [
+      const existing = [
         { range: { bytes: { from: 0, to: 1024 } } },
         { $state: { store: 'appState' }, query: { match: { _term: { query: 'apache', type: 'phrase' } } } }
       ];
-      let filters = [
+      const filters = [
         { range: { bytes: { from: 1024, to: 2048 } } },
         { $state: { store: 'globalState' }, query: { match: { _term: { query: 'apache', type: 'phrase' } } } }
       ];
-      let results = dedupFilters(existing, filters);
+      const results = dedupFilters(existing, filters);
       expect(results).to.contain(filters[0]);
       expect(results).to.not.contain(filters[1]);
     });
diff --git a/src/ui/public/filter_bar/lib/__tests__/extract_time_filter.js b/src/ui/public/filter_bar/lib/__tests__/extract_time_filter.js
index d38746497fd85..fa9cc9bca027d 100644
--- a/src/ui/public/filter_bar/lib/__tests__/extract_time_filter.js
+++ b/src/ui/public/filter_bar/lib/__tests__/extract_time_filter.js
@@ -22,7 +22,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the matching filter for the defualt time field', function (done) {
-      let filters = [
+      const filters = [
         { meta: { index: 'logstash-*' }, query: { match: { _type:  { query: 'apache', type: 'phrase' } } } },
         { meta: { index: 'logstash-*' }, range: { 'time': { gt: 1388559600000, lt: 1388646000000 } } }
       ];
@@ -34,7 +34,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should not return the non-matching filter for the defualt time field', function (done) {
-      let filters = [
+      const filters = [
         { meta: { index: 'logstash-*' }, query: { match: { _type:  { query: 'apache', type: 'phrase' } } } },
         { meta: { index: 'logstash-*' }, range: { '@timestamp': { gt: 1388559600000, lt: 1388646000000 } } }
       ];
diff --git a/src/ui/public/filter_bar/lib/__tests__/filter_applied_and_unwrap.js b/src/ui/public/filter_bar/lib/__tests__/filter_applied_and_unwrap.js
index 196b0acd2bc88..356ff3c06d1b9 100644
--- a/src/ui/public/filter_bar/lib/__tests__/filter_applied_and_unwrap.js
+++ b/src/ui/public/filter_bar/lib/__tests__/filter_applied_and_unwrap.js
@@ -3,13 +3,13 @@ import filterAppliedAndUnwrap from 'ui/filter_bar/lib/filter_applied_and_unwrap'
 describe('Filter Bar Directive', function () {
   describe('filterAppliedAndUnwrap()', function () {
 
-    let filters = [
+    const filters = [
       { meta: { apply: true }, exists: { field: '_type' } },
       { meta: { apply: false }, query: { query_string: { query: 'foo:bar' } } }
     ];
 
     it('should filter the applied and unwrap the filter', function () {
-      let results = filterAppliedAndUnwrap(filters);
+      const results = filterAppliedAndUnwrap(filters);
       expect(results).to.have.length(1);
       expect(results[0]).to.eql(filters[0]);
     });
diff --git a/src/ui/public/filter_bar/lib/__tests__/filter_out_time_based_filter.js b/src/ui/public/filter_bar/lib/__tests__/filter_out_time_based_filter.js
index f4a23ce6dfc3b..97b6c99004644 100644
--- a/src/ui/public/filter_bar/lib/__tests__/filter_out_time_based_filter.js
+++ b/src/ui/public/filter_bar/lib/__tests__/filter_out_time_based_filter.js
@@ -23,7 +23,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the matching filter for the defualt time field', function (done) {
-      let filters = [
+      const filters = [
         { meta: { index: 'logstash-*' }, query: { match: { _type:  { query: 'apache', type: 'phrase' } } } },
         { meta: { index: 'logstash-*' }, range: { 'time': { gt: 1388559600000, lt: 1388646000000 } } }
       ];
diff --git a/src/ui/public/filter_bar/lib/__tests__/generate_mapping_chain.js b/src/ui/public/filter_bar/lib/__tests__/generate_mapping_chain.js
index 6dc126c323a4d..43fb21bf7c7a0 100644
--- a/src/ui/public/filter_bar/lib/__tests__/generate_mapping_chain.js
+++ b/src/ui/public/filter_bar/lib/__tests__/generate_mapping_chain.js
@@ -19,13 +19,13 @@ describe('Filter Bar Directive', function () {
 
 
     it('should create a chaning function which calls the next function if the promise is rejected', function (done) {
-      let filter = {};
-      let mapping = sinon.stub();
+      const filter = {};
+      const mapping = sinon.stub();
       mapping.returns(Promise.reject(filter));
-      let mappingChainFn = generateMappingChain(mapping);
-      let next = sinon.stub();
+      const mappingChainFn = generateMappingChain(mapping);
+      const next = sinon.stub();
       next.returns(Promise.resolve('good'));
-      let chain = mappingChainFn(next);
+      const chain = mappingChainFn(next);
       chain(filter).then(function (result) {
         expect(result).to.be('good');
         sinon.assert.calledOnce(next);
@@ -35,12 +35,12 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should create a chaning function which DOES NOT call the next function if the result is resolved', function (done) {
-      let mapping = sinon.stub();
+      const mapping = sinon.stub();
       mapping.returns(Promise.resolve('good'));
-      let mappingChainFn = generateMappingChain(mapping);
-      let next = sinon.stub();
+      const mappingChainFn = generateMappingChain(mapping);
+      const next = sinon.stub();
       next.returns(Promise.resolve('bad'));
-      let chain = mappingChainFn(next);
+      const chain = mappingChainFn(next);
       chain({}).then(function (result) {
         expect(result).to.be('good');
         sinon.assert.notCalled(next);
@@ -50,11 +50,11 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should resolve result for the mapping function', function (done) {
-      let mapping = sinon.stub();
+      const mapping = sinon.stub();
       mapping.returns(Promise.resolve({ key: 'test', value: 'example' }));
-      let mappingChainFn = generateMappingChain(mapping);
-      let next = sinon.stub();
-      let chain = mappingChainFn(next);
+      const mappingChainFn = generateMappingChain(mapping);
+      const next = sinon.stub();
+      const chain = mappingChainFn(next);
       chain({}).then(function (result) {
         sinon.assert.notCalled(next);
         expect(result).to.eql({ key: 'test', value: 'example' });
@@ -64,11 +64,11 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should call the mapping function with the argument to the chain', function (done) {
-      let mapping = sinon.stub();
+      const mapping = sinon.stub();
       mapping.returns(Promise.resolve({ key: 'test', value: 'example' }));
-      let mappingChainFn = generateMappingChain(mapping);
-      let next = sinon.stub();
-      let chain = mappingChainFn(next);
+      const mappingChainFn = generateMappingChain(mapping);
+      const next = sinon.stub();
+      const chain = mappingChainFn(next);
       chain({ test: 'example' }).then(function (result) {
         sinon.assert.calledOnce(mapping);
         expect(mapping.args[0][0]).to.eql({ test: 'example' });
@@ -80,13 +80,13 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should resolve result for the next function', function (done) {
-      let filter = {};
-      let mapping = sinon.stub();
+      const filter = {};
+      const mapping = sinon.stub();
       mapping.returns(Promise.reject(filter));
-      let mappingChainFn = generateMappingChain(mapping);
-      let next = sinon.stub();
+      const mappingChainFn = generateMappingChain(mapping);
+      const next = sinon.stub();
       next.returns(Promise.resolve({ key: 'test', value: 'example' }));
-      let chain = mappingChainFn(next);
+      const chain = mappingChainFn(next);
       chain(filter).then(function (result) {
         sinon.assert.calledOnce(mapping);
         sinon.assert.calledOnce(next);
@@ -97,11 +97,11 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should reject with an error if no functions match', function (done) {
-      let filter = {};
-      let mapping = sinon.stub();
+      const filter = {};
+      const mapping = sinon.stub();
       mapping.returns(Promise.reject(filter));
-      let mappingChainFn = generateMappingChain(mapping);
-      let chain = mappingChainFn();
+      const mappingChainFn = generateMappingChain(mapping);
+      const chain = mappingChainFn();
       chain(filter).catch(function (err) {
         expect(err).to.be.an(Error);
         expect(err.message).to.be('No mappings have been found for filter.');
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_and_flatten_filters.js b/src/ui/public/filter_bar/lib/__tests__/map_and_flatten_filters.js
index e3eca25525df3..faf39d3d60f4a 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_and_flatten_filters.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_and_flatten_filters.js
@@ -21,7 +21,7 @@ describe('Filter Bar Directive', function () {
       $rootScope = _$rootScope_;
     }));
 
-    let filters = [
+    const filters = [
       null,
       [
         { meta: { index: 'logstash-*' }, exists: { field: '_type' } },
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_default.js b/src/ui/public/filter_bar/lib/__tests__/map_default.js
index 3bc66ac578b24..721283f51a109 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_default.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_default.js
@@ -13,7 +13,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters', function (done) {
-      let filter = { query: { match_all: {} } };
+      const filter = { query: { match_all: {} } };
       mapDefault(filter).then(function (result) {
         expect(result).to.have.property('key', 'query');
         expect(result).to.have.property('value', '{"match_all":{}}');
@@ -23,7 +23,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should work with undefined filter types', function (done) {
-      let filter = {
+      const filter = {
         'bool': {
           'must': {
             'term': {
@@ -41,7 +41,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined if there is no valid key', function (done) {
-      let filter = { meta: {} };
+      const filter = { meta: {} };
       mapDefault(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_exists.js b/src/ui/public/filter_bar/lib/__tests__/map_exists.js
index aaaf417d5b2ac..5fea9cea76b54 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_exists.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_exists.js
@@ -13,7 +13,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters', function (done) {
-      let filter = { exists: { field: '_type' } };
+      const filter = { exists: { field: '_type' } };
       mapExists(filter).then(function (result) {
         expect(result).to.have.property('key', 'exists');
         expect(result).to.have.property('value', '_type');
@@ -23,7 +23,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined for none matching', function (done) {
-      let filter = { query: { match: { query: 'foo' } } };
+      const filter = { query: { match: { query: 'foo' } } };
       mapExists(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_filter.js b/src/ui/public/filter_bar/lib/__tests__/map_filter.js
index 108bc7933cb26..52641afb8d238 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_filter.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_filter.js
@@ -23,7 +23,7 @@ describe('Filter Bar Directive', function () {
 
   describe('mapFilter()', function () {
     it('should map query filters', function (done) {
-      let before = { meta: { index: 'logstash-*' }, query: { match: { '_type': { query: 'apache' } } } };
+      const before = { meta: { index: 'logstash-*' }, query: { match: { '_type': { query: 'apache' } } } };
       mapFilter(before).then(function (after) {
         expect(after).to.have.property('meta');
         expect(after.meta).to.have.property('key', '_type');
@@ -36,7 +36,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should map exists filters', function (done) {
-      let before = { meta: { index: 'logstash-*' }, exists: { field: '@timestamp' } };
+      const before = { meta: { index: 'logstash-*' }, exists: { field: '@timestamp' } };
       mapFilter(before).then(function (after) {
         expect(after).to.have.property('meta');
         expect(after.meta).to.have.property('key', 'exists');
@@ -49,7 +49,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should map missing filters', function (done) {
-      let before = { meta: { index: 'logstash-*' }, missing: { field: '@timestamp' } };
+      const before = { meta: { index: 'logstash-*' }, missing: { field: '@timestamp' } };
       mapFilter(before).then(function (after) {
         expect(after).to.have.property('meta');
         expect(after.meta).to.have.property('key', 'missing');
@@ -62,7 +62,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should map json filter', function (done) {
-      let before = { meta: { index: 'logstash-*' }, query: { match_all: {} } };
+      const before = { meta: { index: 'logstash-*' }, query: { match_all: {} } };
       mapFilter(before).then(function (after) {
         expect(after).to.have.property('meta');
         expect(after.meta).to.have.property('key', 'query');
@@ -75,7 +75,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should finish with a catch', function (done) {
-      let before = { meta: { index: 'logstash-*' }};
+      const before = { meta: { index: 'logstash-*' }};
       mapFilter(before).catch(function (error) {
         expect(error).to.be.an(Error);
         expect(error.message).to.be('No mappings have been found for filter.');
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_flatten_and_wrap_filters.js b/src/ui/public/filter_bar/lib/__tests__/map_flatten_and_wrap_filters.js
index c817825457802..59ab36e8414b8 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_flatten_and_wrap_filters.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_flatten_and_wrap_filters.js
@@ -22,7 +22,7 @@ describe('Filter Bar Directive', function () {
       $rootScope = _$rootScope_;
     }));
 
-    let filters = [
+    const filters = [
       null,
       [
         { meta: { index: 'logstash-*' }, exists: { field: '_type' } },
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_geo_bounding_box.js b/src/ui/public/filter_bar/lib/__tests__/map_geo_bounding_box.js
index 96e891b9e8d2e..19d356a58059e 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_geo_bounding_box.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_geo_bounding_box.js
@@ -22,7 +22,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters with bounds', function (done) {
-      let filter = {
+      const filter = {
         meta: {
           index: 'logstash-*'
         },
@@ -50,7 +50,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined for none matching', function (done) {
-      let filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
+      const filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
       mapGeoBoundingBox(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_missing.js b/src/ui/public/filter_bar/lib/__tests__/map_missing.js
index 6f45c43528225..f3cecf7dec34e 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_missing.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_missing.js
@@ -14,7 +14,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters', function (done) {
-      let filter = { missing: { field: '_type' } };
+      const filter = { missing: { field: '_type' } };
       mapMissing(filter).then(function (result) {
         expect(result).to.have.property('key', 'missing');
         expect(result).to.have.property('value', '_type');
@@ -24,7 +24,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined for none matching', function (done) {
-      let filter = { query: { match: { query: 'foo' } } };
+      const filter = { query: { match: { query: 'foo' } } };
       mapMissing(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_query_string.js b/src/ui/public/filter_bar/lib/__tests__/map_query_string.js
index 2913e0b77a860..41995d99608d6 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_query_string.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_query_string.js
@@ -12,7 +12,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters', function (done) {
-      let filter = { query: { query_string: { query: 'foo:bar' } } };
+      const filter = { query: { query_string: { query: 'foo:bar' } } };
       mapQueryString(filter).then(function (result) {
         expect(result).to.have.property('key', 'query');
         expect(result).to.have.property('value', 'foo:bar');
@@ -22,7 +22,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined for none matching', function (done) {
-      let filter = { query: { match: { query: 'foo' } } };
+      const filter = { query: { match: { query: 'foo' } } };
       mapQueryString(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_range.js b/src/ui/public/filter_bar/lib/__tests__/map_range.js
index 85fff761b36c4..653aedee1665b 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_range.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_range.js
@@ -22,7 +22,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters with gt/lt', function (done) {
-      let filter = { meta: { index: 'logstash-*' }, range: { bytes: { lt: 2048, gt: 1024 } } };
+      const filter = { meta: { index: 'logstash-*' }, range: { bytes: { lt: 2048, gt: 1024 } } };
       mapRange(filter).then(function (result) {
         expect(result).to.have.property('key', 'bytes');
         expect(result).to.have.property('value', '1,024 to 2,048');
@@ -32,7 +32,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return the key and value for matching filters with gte/lte', function (done) {
-      let filter = { meta: { index: 'logstash-*' }, range: { bytes: { lte: 2048, gte: 1024 } } };
+      const filter = { meta: { index: 'logstash-*' }, range: { bytes: { lte: 2048, gte: 1024 } } };
       mapRange(filter).then(function (result) {
         expect(result).to.have.property('key', 'bytes');
         expect(result).to.have.property('value', '1,024 to 2,048');
@@ -42,7 +42,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined for none matching', function (done) {
-      let filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
+      const filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
       mapRange(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_script.js b/src/ui/public/filter_bar/lib/__tests__/map_script.js
index 214b14b6e63d6..ee2d64fae62fd 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_script.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_script.js
@@ -22,7 +22,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters', function (done) {
-      let filter = {
+      const filter = {
         meta: { index: 'logstash-*', field: 'script number' },
         script: {script: { inline: 'doc["script number"].value * 5', params: { value: 35}}}
       };
@@ -35,7 +35,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined for none matching', function (done) {
-      let filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
+      const filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
       mapScript(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
@@ -44,7 +44,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return a value for a range/histogram filter from a scripted field', (done) => {
-      let filter = {
+      const filter = {
         meta: {
           index: 'logstash-*',
           formattedValue: '1,000.00 to 2,000.00',
diff --git a/src/ui/public/filter_bar/lib/__tests__/map_terms.js b/src/ui/public/filter_bar/lib/__tests__/map_terms.js
index f2971ad91d7ce..aac44755000b8 100644
--- a/src/ui/public/filter_bar/lib/__tests__/map_terms.js
+++ b/src/ui/public/filter_bar/lib/__tests__/map_terms.js
@@ -22,7 +22,7 @@ describe('Filter Bar Directive', function () {
     }));
 
     it('should return the key and value for matching filters', function (done) {
-      let filter = { meta: { index: 'logstash-*' }, query: { match: { _type: { query: 'apache', type: 'phrase' } } } };
+      const filter = { meta: { index: 'logstash-*' }, query: { match: { _type: { query: 'apache', type: 'phrase' } } } };
       mapTerms(filter).then(function (result) {
         expect(result).to.have.property('key', '_type');
         expect(result).to.have.property('value', 'apache');
@@ -32,7 +32,7 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return undefined for none matching', function (done) {
-      let filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
+      const filter = { meta: { index: 'logstash-*' }, query: { query_string: { query: 'foo:bar' } } };
       mapTerms(filter).catch(function (result) {
         expect(result).to.be(filter);
         done();
diff --git a/src/ui/public/filter_bar/lib/__tests__/only_disabled.js b/src/ui/public/filter_bar/lib/__tests__/only_disabled.js
index e7bc342a5d8b1..f9e170b9afd1d 100644
--- a/src/ui/public/filter_bar/lib/__tests__/only_disabled.js
+++ b/src/ui/public/filter_bar/lib/__tests__/only_disabled.js
@@ -4,71 +4,71 @@ describe('Filter Bar Directive', function () {
   describe('onlyDisabled()', function () {
 
     it('should return true if all filters are disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: true } },
         { meta: { disabled: true } },
         { meta: { disabled: true } }
       ];
-      let newFilters = [{ meta: { disabled: true } }];
+      const newFilters = [{ meta: { disabled: true } }];
       expect(onlyDisabled(newFilters, filters)).to.be(true);
     });
 
     it('should return false if all filters are not disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: false } },
         { meta: { disabled: false } },
         { meta: { disabled: false } }
       ];
-      let newFilters = [{ meta: { disabled: false } }];
+      const newFilters = [{ meta: { disabled: false } }];
       expect(onlyDisabled(newFilters, filters)).to.be(false);
     });
 
     it('should return false if only old filters are disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: true } },
         { meta: { disabled: true } },
         { meta: { disabled: true } }
       ];
-      let newFilters = [{ meta: { disabled: false } }];
+      const newFilters = [{ meta: { disabled: false } }];
       expect(onlyDisabled(newFilters, filters)).to.be(false);
     });
 
     it('should return false if new filters are not disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: false } },
         { meta: { disabled: false } },
         { meta: { disabled: false } }
       ];
-      let newFilters = [{ meta: { disabled: true } }];
+      const newFilters = [{ meta: { disabled: true } }];
       expect(onlyDisabled(newFilters, filters)).to.be(false);
     });
 
     it('should return true when all removed filters were disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: true } },
         { meta: { disabled: true } },
         { meta: { disabled: true } }
       ];
-      let newFilters = [];
+      const newFilters = [];
       expect(onlyDisabled(newFilters, filters)).to.be(true);
     });
 
     it('should return false when all removed filters were not disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: false } },
         { meta: { disabled: false } },
         { meta: { disabled: false } }
       ];
-      let newFilters = [];
+      const newFilters = [];
       expect(onlyDisabled(newFilters, filters)).to.be(false);
     });
 
     it('should return true if all changed filters are disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: true, negate: false } },
         { meta: { disabled: true, negate: false } }
       ];
-      let newFilters = [
+      const newFilters = [
         { meta: { disabled: true, negate: true } },
         { meta: { disabled: true, negate: true } }
       ];
@@ -76,31 +76,31 @@ describe('Filter Bar Directive', function () {
     });
 
     it('should return false if all filters remove were not disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: false } },
         { meta: { disabled: false } },
         { meta: { disabled: true } }
       ];
-      let newFilters = [{ meta: { disabled: false } }];
+      const newFilters = [{ meta: { disabled: false } }];
       expect(onlyDisabled(newFilters, filters)).to.be(false);
     });
 
     it('should return false when all removed filters are not disabled', function () {
-      let filters = [
+      const filters = [
         { meta: { disabled: true } },
         { meta: { disabled: false } },
         { meta: { disabled: true } }
       ];
-      let newFilters = [];
+      const newFilters = [];
       expect(onlyDisabled(newFilters, filters)).to.be(false);
     });
 
     it('should not throw with null filters', function () {
-      let filters = [
+      const filters = [
         null,
         { meta: { disabled: true } }
       ];
-      let newFilters = [];
+      const newFilters = [];
       expect(function () {
         onlyDisabled(newFilters, filters);
       }).to.not.throwError();
diff --git a/src/ui/public/filter_bar/lib/__tests__/uniq_filters.js b/src/ui/public/filter_bar/lib/__tests__/uniq_filters.js
index 391b2dc67dc65..dffe89f96f3c1 100644
--- a/src/ui/public/filter_bar/lib/__tests__/uniq_filters.js
+++ b/src/ui/public/filter_bar/lib/__tests__/uniq_filters.js
@@ -4,16 +4,16 @@ describe('Filter Bar Directive', function () {
   describe('uniqFilter', function () {
 
     it('should filter out dups', function () {
-      let before = [
+      const before = [
         { query: { _type: { match: { query: 'apache', type: 'phrase' } } } },
         { query: { _type: { match: { query: 'apache', type: 'phrase' } } } }
       ];
-      let results = uniqFilters(before);
+      const results = uniqFilters(before);
       expect(results).to.have.length(1);
     });
 
     it('should filter out duplicates, ignoring meta attributes', function () {
-      let before = [
+      const before = [
         {
           meta: { negate: true },
           query: { _type: { match: { query: 'apache', type: 'phrase' } } }
@@ -23,12 +23,12 @@ describe('Filter Bar Directive', function () {
           query: { _type: { match: { query: 'apache', type: 'phrase' } } }
         }
       ];
-      let results = uniqFilters(before);
+      const results = uniqFilters(before);
       expect(results).to.have.length(1);
     });
 
     it('should filter out duplicates, ignoring $state attributes', function () {
-      let before = [
+      const before = [
         {
           $state: { store: 'appState' },
           query: { _type: { match: { query: 'apache', type: 'phrase' } } }
@@ -38,7 +38,7 @@ describe('Filter Bar Directive', function () {
           query: { _type: { match: { query: 'apache', type: 'phrase' } } }
         }
       ];
-      let results = uniqFilters(before);
+      const results = uniqFilters(before);
       expect(results).to.have.length(1);
     });
   });
diff --git a/src/ui/public/filter_bar/lib/change_time_filter.js b/src/ui/public/filter_bar/lib/change_time_filter.js
index 47e991eabe7be..cee9477f09edc 100644
--- a/src/ui/public/filter_bar/lib/change_time_filter.js
+++ b/src/ui/public/filter_bar/lib/change_time_filter.js
@@ -2,8 +2,8 @@ import moment from 'moment';
 import _ from 'lodash';
 export default function changeTimeFilterProvider(timefilter) {
   return function (filter) {
-    let key = _.keys(filter.range)[0];
-    let values = filter.range[key];
+    const key = _.keys(filter.range)[0];
+    const values = filter.range[key];
     timefilter.time.from = moment(values.gt || values.gte);
     timefilter.time.to = moment(values.lt || values.lte);
     timefilter.time.mode = 'absolute';
diff --git a/src/ui/public/filter_bar/lib/compare_filters.js b/src/ui/public/filter_bar/lib/compare_filters.js
index 2cfa19e6d5345..3c903ba19c8f2 100644
--- a/src/ui/public/filter_bar/lib/compare_filters.js
+++ b/src/ui/public/filter_bar/lib/compare_filters.js
@@ -24,7 +24,7 @@ export default function (first, second, comparatorOptions) {
 };
 
 function mapFilter(filter) {
-  let cleaned = _.omit(filter, excludedAttributes);
+  const cleaned = _.omit(filter, excludedAttributes);
   if (comparators.negate) cleaned.negate = filter.meta && !!filter.meta.negate;
   if (comparators.disabled) cleaned.disabled = filter.meta && !!filter.meta.disabled;
   return cleaned;
diff --git a/src/ui/public/filter_bar/lib/extract_time_filter.js b/src/ui/public/filter_bar/lib/extract_time_filter.js
index c13b96a4ffa25..a905cbf593c5d 100644
--- a/src/ui/public/filter_bar/lib/extract_time_filter.js
+++ b/src/ui/public/filter_bar/lib/extract_time_filter.js
@@ -3,12 +3,12 @@ export default function extractTimeFilterProvider(courier, Promise) {
   return Promise.method(function (filters) {
     // Assume all the index patterns are the same since they will be added
     // from the same visualization.
-    let id = _.get(filters, '[0].meta.index');
+    const id = _.get(filters, '[0].meta.index');
     if (id == null) return;
 
     return courier.indexPatterns.get(id).then(function (indexPattern) {
-      let filter = _.find(filters, function (obj) {
-        let key = _.keys(obj.range)[0];
+      const filter = _.find(filters, function (obj) {
+        const key = _.keys(obj.range)[0];
         return key === indexPattern.timeFieldName;
       });
       if (filter && filter.range) {
diff --git a/src/ui/public/filter_bar/lib/filter_out_time_based_filter.js b/src/ui/public/filter_bar/lib/filter_out_time_based_filter.js
index bd033b15fd8d5..91299918558a2 100644
--- a/src/ui/public/filter_bar/lib/filter_out_time_based_filter.js
+++ b/src/ui/public/filter_bar/lib/filter_out_time_based_filter.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 export default function filterOutTimeBaseFilter(courier, Promise) {
   return Promise.method(function (filters) {
-    let id = _.get(filters, '[0].meta.index');
+    const id = _.get(filters, '[0].meta.index');
     if (id == null) return;
 
     return courier.indexPatterns.get(id).then(function (indexPattern) {
diff --git a/src/ui/public/filter_bar/lib/generate_mapping_chain.js b/src/ui/public/filter_bar/lib/generate_mapping_chain.js
index e857804a37775..f27f4a50e2c1e 100644
--- a/src/ui/public/filter_bar/lib/generate_mapping_chain.js
+++ b/src/ui/public/filter_bar/lib/generate_mapping_chain.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 export default function generateMappingChainProvider(Promise) {
 
-  let noop = function () {
+  const noop = function () {
     return Promise.reject(new Error('No mappings have been found for filter.'));
   };
 
diff --git a/src/ui/public/filter_bar/lib/map_and_flatten_filters.js b/src/ui/public/filter_bar/lib/map_and_flatten_filters.js
index f48706eb68f88..ebaf8043e2f65 100644
--- a/src/ui/public/filter_bar/lib/map_and_flatten_filters.js
+++ b/src/ui/public/filter_bar/lib/map_and_flatten_filters.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import FilterBarLibMapFilterProvider from 'ui/filter_bar/lib/map_filter';
 export default function mapAndFlattenFiltersProvider(Private, Promise) {
-  let mapFilter = Private(FilterBarLibMapFilterProvider);
+  const mapFilter = Private(FilterBarLibMapFilterProvider);
   return function (filters) {
     return _(filters)
     .flatten()
diff --git a/src/ui/public/filter_bar/lib/map_default.js b/src/ui/public/filter_bar/lib/map_default.js
index e9f53ed21710e..45a3a2f84071d 100644
--- a/src/ui/public/filter_bar/lib/map_default.js
+++ b/src/ui/public/filter_bar/lib/map_default.js
@@ -2,15 +2,15 @@ import angular from 'angular';
 import _ from 'lodash';
 export default function mapDefaultProvider(Promise) {
 
-  let metaProperty = /(^\$|meta)/;
+  const metaProperty = /(^\$|meta)/;
 
   return function (filter) {
-    let key = _.find(_.keys(filter), function (key) {
+    const key = _.find(_.keys(filter), function (key) {
       return !key.match(metaProperty);
     });
 
     if (key) {
-      let value = angular.toJson(filter[key]);
+      const value = angular.toJson(filter[key]);
       return Promise.resolve({ key: key, value: value });
     }
     return Promise.reject(filter);
diff --git a/src/ui/public/filter_bar/lib/map_filter.js b/src/ui/public/filter_bar/lib/map_filter.js
index 5ff047813f9ef..76e317fb96b0d 100644
--- a/src/ui/public/filter_bar/lib/map_filter.js
+++ b/src/ui/public/filter_bar/lib/map_filter.js
@@ -11,7 +11,7 @@ import MapScriptProvider from './map_script';
 import MapDefaultProvider from './map_default';
 export default function mapFilterProvider(Promise, Private) {
 
-  let generateMappingChain = Private(GenerateMappingChainProvider);
+  const generateMappingChain = Private(GenerateMappingChainProvider);
 
   /** Mappers **/
 
@@ -29,7 +29,7 @@ export default function mapFilterProvider(Promise, Private) {
   // To create a new mapper you just need to create a function
   // that either handles the mapping operation or not
   // and add it here. ProTip: These are executed in order listed
-  let mappers = [
+  const mappers = [
     Private(MapMatchAllProvider),
     Private(MapTermsProvider),
     Private(MapRangeProvider),
@@ -41,14 +41,14 @@ export default function mapFilterProvider(Promise, Private) {
     Private(MapDefaultProvider)
   ];
 
-  let noop = function () {
+  const noop = function () {
     return Promise.reject(new Error('No mappings have been found for filter.'));
   };
 
   // Create a chain of responsibility by reducing all the
   // mappers down into one function.
-  let mapFn = _.reduceRight(mappers, function (memo, map) {
-    let filterChainFn = generateMappingChain(map);
+  const mapFn = _.reduceRight(mappers, function (memo, map) {
+    const filterChainFn = generateMappingChain(map);
     return filterChainFn(memo);
   }, noop);
 
diff --git a/src/ui/public/filter_bar/lib/map_flatten_and_wrap_filters.js b/src/ui/public/filter_bar/lib/map_flatten_and_wrap_filters.js
index f86b5a6e566b1..fb2d0707deafb 100644
--- a/src/ui/public/filter_bar/lib/map_flatten_and_wrap_filters.js
+++ b/src/ui/public/filter_bar/lib/map_flatten_and_wrap_filters.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import FilterBarLibMapAndFlattenFiltersProvider from 'ui/filter_bar/lib/map_and_flatten_filters';
 export default function mapFlattenAndWrapFilters(Private) {
-  let mapAndFlattenFilters = Private(FilterBarLibMapAndFlattenFiltersProvider);
+  const mapAndFlattenFilters = Private(FilterBarLibMapAndFlattenFiltersProvider);
   return function (filters) {
     return mapAndFlattenFilters(filters).then(function (filters) {
       return _.map(filters, function (filter) {
diff --git a/src/ui/public/filter_bar/lib/map_range.js b/src/ui/public/filter_bar/lib/map_range.js
index 5e710b0dd4560..8eeb93eb7c4fc 100644
--- a/src/ui/public/filter_bar/lib/map_range.js
+++ b/src/ui/public/filter_bar/lib/map_range.js
@@ -7,9 +7,9 @@ export default function mapRangeProvider(Promise, courier) {
     .indexPatterns
     .get(filter.meta.index)
     .then(function (indexPattern) {
-      let key = Object.keys(filter.range)[0];
-      let convert = indexPattern.fields.byName[key].format.getConverterFor('text');
-      let range = filter.range[key];
+      const key = Object.keys(filter.range)[0];
+      const convert = indexPattern.fields.byName[key].format.getConverterFor('text');
+      const range = filter.range[key];
 
       let left = has(range, 'gte') ? range.gte : range.gt;
       if (left == null) left = -Infinity;
diff --git a/src/ui/public/filter_bar/lib/only_disabled.js b/src/ui/public/filter_bar/lib/only_disabled.js
index 8bb7cbf23ee91..2513e0ba25566 100644
--- a/src/ui/public/filter_bar/lib/only_disabled.js
+++ b/src/ui/public/filter_bar/lib/only_disabled.js
@@ -1,6 +1,6 @@
 import _ from 'lodash';
 
-let pluckDisabled = function (filter) {
+const pluckDisabled = function (filter) {
   return _.get(filter, 'meta.disabled');
 };
 
diff --git a/src/ui/public/filter_bar/lib/only_state_changed.js b/src/ui/public/filter_bar/lib/only_state_changed.js
index 8fe0cceec830a..048e20929e6c9 100644
--- a/src/ui/public/filter_bar/lib/only_state_changed.js
+++ b/src/ui/public/filter_bar/lib/only_state_changed.js
@@ -1,6 +1,6 @@
 import _ from 'lodash';
 import compareFilters from 'ui/filter_bar/lib/compare_filters';
-let compareOptions = { disabled: true, negate: true };
+const compareOptions = { disabled: true, negate: true };
 
 /**
  * Checks to see if only disabled filters have been changed
@@ -8,7 +8,7 @@ let compareOptions = { disabled: true, negate: true };
  */
 export default function (newFilters, oldFilters) {
   return _.every(newFilters, function (newFilter, i) {
-    let match = _.find(oldFilters, function (oldFilter) {
+    const match = _.find(oldFilters, function (oldFilter) {
       return compareFilters(newFilter, oldFilter, compareOptions);
     });
     return !!match;
diff --git a/src/ui/public/filter_bar/push_filter.js b/src/ui/public/filter_bar/push_filter.js
index 6375791b05826..95e524b8074f2 100644
--- a/src/ui/public/filter_bar/push_filter.js
+++ b/src/ui/public/filter_bar/push_filter.js
@@ -7,8 +7,8 @@ export default function () {
       // Hierarchical and tabular data set their aggConfigResult parameter
       // differently because of how the point is rewritten between the two. So
       // we need to check if the point.orig is set, if not use try the point.aggConfigResult
-      let filters = _.clone($state.filters || []);
-      let pendingFilter = { meta: { negate: negate, index: index }};
+      const filters = _.clone($state.filters || []);
+      const pendingFilter = { meta: { negate: negate, index: index }};
       _.extend(pendingFilter, filter);
       filters.push(pendingFilter);
       $state.filters = filters;
diff --git a/src/ui/public/filter_bar/query_filter.js b/src/ui/public/filter_bar/query_filter.js
index 7647586b0c44f..679bb66fcb432 100644
--- a/src/ui/public/filter_bar/query_filter.js
+++ b/src/ui/public/filter_bar/query_filter.js
@@ -8,21 +8,21 @@ import EventsProvider from 'ui/events';
 import FilterBarLibMapAndFlattenFiltersProvider from 'ui/filter_bar/lib/map_and_flatten_filters';
 
 export default function (Private, $rootScope, getAppState, globalState, config) {
-  let EventEmitter = Private(EventsProvider);
-  let mapAndFlattenFilters = Private(FilterBarLibMapAndFlattenFiltersProvider);
+  const EventEmitter = Private(EventsProvider);
+  const mapAndFlattenFilters = Private(FilterBarLibMapAndFlattenFiltersProvider);
 
-  let queryFilter = new EventEmitter();
+  const queryFilter = new EventEmitter();
 
   queryFilter.getFilters = function () {
-    let compareOptions = { disabled: true, negate: true };
-    let appFilters = queryFilter.getAppFilters();
-    let globalFilters = queryFilter.getGlobalFilters();
+    const compareOptions = { disabled: true, negate: true };
+    const appFilters = queryFilter.getAppFilters();
+    const globalFilters = queryFilter.getGlobalFilters();
 
     return uniqFilters(globalFilters.concat(appFilters), compareOptions);
   };
 
   queryFilter.getAppFilters = function () {
-    let appState = getAppState();
+    const appState = getAppState();
     if (!appState || !appState.filters) return [];
 
     // Work around for https://github.com/elastic/kibana/issues/5896
@@ -49,7 +49,7 @@ export default function (Private, $rootScope, getAppState, globalState, config)
   queryFilter.addFilters = function (filters, global) {
 
     if (global === undefined) {
-      let configDefault = config.get('filters:pinnedByDefault');
+      const configDefault = config.get('filters:pinnedByDefault');
 
       if (configDefault === false || configDefault === true) {
         global = configDefault;
@@ -57,8 +57,8 @@ export default function (Private, $rootScope, getAppState, globalState, config)
     }
 
     // Determine the state for the new filter (whether to pass the filter through other apps or not)
-    let appState = getAppState();
-    let filterState = (global) ? globalState : appState;
+    const appState = getAppState();
+    const filterState = (global) ? globalState : appState;
 
     if (!_.isArray(filters)) {
       filters = [filters];
@@ -79,8 +79,8 @@ export default function (Private, $rootScope, getAppState, globalState, config)
    * @param {object} matchFilter The filter to remove
    */
   queryFilter.removeFilter = function (matchFilter) {
-    let appState = getAppState();
-    let filter = _.omit(matchFilter, ['$$hashKey']);
+    const appState = getAppState();
+    const filter = _.omit(matchFilter, ['$$hashKey']);
     let state;
     let index;
 
@@ -108,11 +108,11 @@ export default function (Private, $rootScope, getAppState, globalState, config)
   * @returns {object} Promise that resolves to the new filter on a successful merge
   */
   queryFilter.updateFilter = function (filter) {
-    let mergedFilter = _.assign({}, filter.source, filter.model);
+    const mergedFilter = _.assign({}, filter.source, filter.model);
     mergedFilter.meta.alias = filter.alias;
     //If the filter type is changed we want to discard the old type
     //when merging changes back in
-    let filterTypeReplaced = filter.model[filter.type] !== mergedFilter[filter.type];
+    const filterTypeReplaced = filter.model[filter.type] !== mergedFilter[filter.type];
     if (filterTypeReplaced) {
       delete mergedFilter[filter.type];
     }
@@ -124,7 +124,7 @@ export default function (Private, $rootScope, getAppState, globalState, config)
    * Removes all filters
    */
   queryFilter.removeAll = function () {
-    let appState = getAppState();
+    const appState = getAppState();
     appState.filters = [];
     globalState.filters = [];
   };
@@ -137,7 +137,7 @@ export default function (Private, $rootScope, getAppState, globalState, config)
    */
   queryFilter.toggleFilter = function (filter, force) {
     // Toggle the disabled flag
-    let disabled = _.isUndefined(force) ? !filter.meta.disabled : !!force;
+    const disabled = _.isUndefined(force) ? !filter.meta.disabled : !!force;
     filter.meta.disabled = disabled;
     return filter;
   };
@@ -182,20 +182,20 @@ export default function (Private, $rootScope, getAppState, globalState, config)
    * @returns {object} updated filter
    */
   queryFilter.pinFilter = function (filter, force) {
-    let appState = getAppState();
+    const appState = getAppState();
     if (!appState) return filter;
 
     // ensure that both states have a filters property
     if (!_.isArray(globalState.filters)) globalState.filters = [];
     if (!_.isArray(appState.filters)) appState.filters = [];
 
-    let appIndex = _.indexOf(appState.filters, filter);
+    const appIndex = _.indexOf(appState.filters, filter);
 
     if (appIndex !== -1 && force !== false) {
       appState.filters.splice(appIndex, 1);
       globalState.filters.push(filter);
     } else {
-      let globalIndex = _.indexOf(globalState.filters, filter);
+      const globalIndex = _.indexOf(globalState.filters, filter);
 
       if (globalIndex === -1 || force === true) return filter;
 
@@ -226,7 +226,7 @@ export default function (Private, $rootScope, getAppState, globalState, config)
    * Rids filter list of null values and replaces state if any nulls are found
    */
   function validateStateFilters(state) {
-    let compacted = _.compact(state.filters);
+    const compacted = _.compact(state.filters);
     if (state.filters.length !== compacted.length) {
       state.filters = compacted;
       state.replace();
@@ -240,7 +240,7 @@ export default function (Private, $rootScope, getAppState, globalState, config)
    * @returns {object} Resulting filter list, app and global combined
    */
   function saveState() {
-    let appState = getAppState();
+    const appState = getAppState();
     if (appState) appState.save();
     globalState.save();
   }
@@ -256,7 +256,7 @@ export default function (Private, $rootScope, getAppState, globalState, config)
 
   // helper to run a function on all filters in all states
   function executeOnFilters(fn) {
-    let appState = getAppState();
+    const appState = getAppState();
     let globalFilters = [];
     let appFilters = [];
 
@@ -268,13 +268,13 @@ export default function (Private, $rootScope, getAppState, globalState, config)
 
   function mergeStateFilters(gFilters, aFilters, compareOptions) {
     // ensure we don't mutate the filters passed in
-    let globalFilters = gFilters ? _.cloneDeep(gFilters) : [];
-    let appFilters = aFilters ? _.cloneDeep(aFilters) : [];
+    const globalFilters = gFilters ? _.cloneDeep(gFilters) : [];
+    const appFilters = aFilters ? _.cloneDeep(aFilters) : [];
     compareOptions = _.defaults(compareOptions || {}, { disabled: true });
 
     // existing globalFilters should be mutated by appFilters
     _.each(appFilters, function (filter, i) {
-      let match = _.find(globalFilters, function (globalFilter) {
+      const match = _.find(globalFilters, function (globalFilter) {
         return compareFilters(globalFilter, filter, compareOptions);
       });
 
@@ -306,7 +306,7 @@ export default function (Private, $rootScope, getAppState, globalState, config)
 
     function initAppStateWatchers() {
       // multi watch on the app and global states
-      let stateWatchers = [{
+      const stateWatchers = [{
         fn: $rootScope.$watch,
         deep: true,
         get: queryFilter.getGlobalFilters
@@ -325,14 +325,14 @@ export default function (Private, $rootScope, getAppState, globalState, config)
         let doFetch = false;
 
         // reconcile filter in global and app states
-        let filters = mergeStateFilters(next[0], next[1]);
-        let globalFilters = filters[0];
-        let appFilters = filters[1];
-        let appState = getAppState();
+        const filters = mergeStateFilters(next[0], next[1]);
+        const globalFilters = filters[0];
+        const appFilters = filters[1];
+        const appState = getAppState();
 
         // save the state, as it may have updated
-        let globalChanged = !_.isEqual(next[0], globalFilters);
-        let appChanged = !_.isEqual(next[1], appFilters);
+        const globalChanged = !_.isEqual(next[0], globalFilters);
+        const appChanged = !_.isEqual(next[1], appFilters);
 
         // the filters were changed, apply to state (re-triggers this watcher)
         if (globalChanged || appChanged) {
@@ -359,8 +359,8 @@ export default function (Private, $rootScope, getAppState, globalState, config)
           let oldFilters = [];
 
           stateWatchers.forEach(function (watcher, i) {
-            let nextVal = next[i];
-            let prevVal = prev[i];
+            const nextVal = next[i];
+            const prevVal = prev[i];
             newFilters = newFilters.concat(nextVal);
             oldFilters = oldFilters.concat(prevVal);
 
diff --git a/src/ui/public/filter_manager/__tests__/filter_manager.js b/src/ui/public/filter_manager/__tests__/filter_manager.js
index 618b969b9589b..29f20a1e6b109 100644
--- a/src/ui/public/filter_manager/__tests__/filter_manager.js
+++ b/src/ui/public/filter_manager/__tests__/filter_manager.js
@@ -12,7 +12,7 @@ let appState;
 
 function checkAddFilters(length, comps, idx) {
   idx = idx || 0;
-  let filters = queryFilter.addFilters.getCall(idx).args[0];
+  const filters = queryFilter.addFilters.getCall(idx).args[0];
 
   expect(filters.length).to.be(length);
   if (!_.isArray(comps)) return;
@@ -114,7 +114,7 @@ describe('Filter Manager', function () {
     checkAddFilters(0, null, 3);
     expect(appState.filters).to.have.length(2);
 
-    let scriptedField = {name: 'scriptedField', scripted: true, script: 1};
+    const scriptedField = {name: 'scriptedField', scripted: true, script: 1};
     filterManager.add(scriptedField, 1, '+', 'myIndex');
     checkAddFilters(1, [{
       meta: {index: 'myIndex', negate: false, field: 'scriptedField'},
diff --git a/src/ui/public/filter_manager/filter_manager.js b/src/ui/public/filter_manager/filter_manager.js
index c856ab0c07746..0d485745301db 100644
--- a/src/ui/public/filter_manager/filter_manager.js
+++ b/src/ui/public/filter_manager/filter_manager.js
@@ -2,21 +2,21 @@ import _ from 'lodash';
 import FilterBarQueryFilterProvider from 'ui/filter_bar/query_filter';
 // Adds a filter to a passed state
 export default function (Private) {
-  let queryFilter = Private(FilterBarQueryFilterProvider);
-  let filterManager = {};
+  const queryFilter = Private(FilterBarQueryFilterProvider);
+  const filterManager = {};
 
   filterManager.add = function (field, values, operation, index) {
     values = _.isArray(values) ? values : [values];
-    let fieldName = _.isObject(field) ? field.name : field;
-    let filters = _.flatten([queryFilter.getAppFilters()]);
-    let newFilters = [];
+    const fieldName = _.isObject(field) ? field.name : field;
+    const filters = _.flatten([queryFilter.getAppFilters()]);
+    const newFilters = [];
 
-    let negate = (operation === '-');
+    const negate = (operation === '-');
 
     // TODO: On array fields, negating does not negate the combination, rather all terms
     _.each(values, function (value) {
       let filter;
-      let existing = _.find(filters, function (filter) {
+      const existing = _.find(filters, function (filter) {
         if (!filter) return;
 
         if (fieldName === '_exists_' && filter.exists) {
diff --git a/src/ui/public/filter_manager/lib/__tests__/range.js b/src/ui/public/filter_manager/lib/__tests__/range.js
index 94bee0426f4b6..4b138edd012ed 100644
--- a/src/ui/public/filter_manager/lib/__tests__/range.js
+++ b/src/ui/public/filter_manager/lib/__tests__/range.js
@@ -54,9 +54,9 @@ describe('Filter Manager', function () {
 
     it('to use the right operator for each of gte, gt, lt and lte', function () {
       _.each({gte: '>=', gt: '>', lte: '<=', lt: '<'}, function (operator, key) {
-        let params = {};
+        const params = {};
         params[key] = 5;
-        let filter = fn(indexPattern.fields.byName['script number'], params, indexPattern);
+        const filter = fn(indexPattern.fields.byName['script number'], params, indexPattern);
 
         expect(filter.script.script.inline).to.be('(' + indexPattern.fields.byName['script number'].script + ')' + operator + key);
         expect(filter.script.script.params[key]).to.be(5);
diff --git a/src/ui/public/filter_manager/lib/phrase.js b/src/ui/public/filter_manager/lib/phrase.js
index fbc2f45657d01..5a1abeedc1f45 100644
--- a/src/ui/public/filter_manager/lib/phrase.js
+++ b/src/ui/public/filter_manager/lib/phrase.js
@@ -1,6 +1,6 @@
 import _ from 'lodash';
 export default function buildPhraseFilter(field, value, indexPattern) {
-  let filter = { meta: { index: indexPattern.id} };
+  const filter = { meta: { index: indexPattern.id} };
 
   if (field.scripted) {
     _.set(filter, 'script.script', {
diff --git a/src/ui/public/filters/__tests__/field_type.js b/src/ui/public/filters/__tests__/field_type.js
index 215a34be2c206..fb4676ddfd594 100644
--- a/src/ui/public/filters/__tests__/field_type.js
+++ b/src/ui/public/filters/__tests__/field_type.js
@@ -9,7 +9,7 @@ let filter;
 
 let types;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
@@ -59,7 +59,7 @@ describe('fieldType array filter', function () {
   });
 
   it('should allow negation', function () {
-    let resultNames = _.pluck(filter(types, '!string'), 'name');
+    const resultNames = _.pluck(filter(types, '!string'), 'name');
     expect(resultNames).to.eql(['n1', 'n2', 'i1', 'd1']);
   });
 });
diff --git a/src/ui/public/filters/__tests__/label.js b/src/ui/public/filters/__tests__/label.js
index 920f6fb90f0bd..db604c0fc6413 100644
--- a/src/ui/public/filters/__tests__/label.js
+++ b/src/ui/public/filters/__tests__/label.js
@@ -9,7 +9,7 @@ import 'plugins/kibana/discover/index';
 
 let filter;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/filters/__tests__/moment.js b/src/ui/public/filters/__tests__/moment.js
index 1d4a330251e5b..fb05c6e2fb604 100644
--- a/src/ui/public/filters/__tests__/moment.js
+++ b/src/ui/public/filters/__tests__/moment.js
@@ -9,10 +9,10 @@ import 'ui/filters/moment';
 let filter;
 
 let config;
-let anchor = '2014-01-01T06:06:06.666';
+const anchor = '2014-01-01T06:06:06.666';
 let clock;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/filters/__tests__/rison.js b/src/ui/public/filters/__tests__/rison.js
index 2412d032da994..9e720bcf9a7d4 100644
--- a/src/ui/public/filters/__tests__/rison.js
+++ b/src/ui/public/filters/__tests__/rison.js
@@ -8,7 +8,7 @@ import 'plugins/kibana/discover/index';
 let rison;
 let risonDecode;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
@@ -20,13 +20,13 @@ let init = function (expandable) {
 };
 
 describe('rison filters', function () {
-  let testObj = {
+  const testObj = {
     time: {
       from: 'now-15m',
       to: 'now'
     }
   };
-  let testRison = '(time:(from:now-15m,to:now))';
+  const testRison = '(time:(from:now-15m,to:now))';
 
   beforeEach(function () {
     init();
diff --git a/src/ui/public/filters/__tests__/short_dots.js b/src/ui/public/filters/__tests__/short_dots.js
index cacfab16b8676..acd92001e0cb0 100644
--- a/src/ui/public/filters/__tests__/short_dots.js
+++ b/src/ui/public/filters/__tests__/short_dots.js
@@ -10,7 +10,7 @@ let filter;
 
 let config;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/filters/__tests__/start_from.js b/src/ui/public/filters/__tests__/start_from.js
index 3f03605c27f3d..2377a06fd82fb 100644
--- a/src/ui/public/filters/__tests__/start_from.js
+++ b/src/ui/public/filters/__tests__/start_from.js
@@ -6,7 +6,7 @@ import 'ui/filters/start_from';
 
 let filter;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/filters/__tests__/uriescape.js b/src/ui/public/filters/__tests__/uriescape.js
index 8baa7469ccf5c..4a1acfb404d29 100644
--- a/src/ui/public/filters/__tests__/uriescape.js
+++ b/src/ui/public/filters/__tests__/uriescape.js
@@ -7,7 +7,7 @@ import 'plugins/kibana/discover/index';
 
 let filter;
 
-let init = function (expandable) {
+const init = function (expandable) {
   // Load the application
   ngMock.module('kibana');
 
diff --git a/src/ui/public/filters/_prop_filter.js b/src/ui/public/filters/_prop_filter.js
index 19d817df80662..f2893127edf9b 100644
--- a/src/ui/public/filters/_prop_filter.js
+++ b/src/ui/public/filters/_prop_filter.js
@@ -23,7 +23,7 @@ function propFilter(prop) {
     if (!_.isArray(filters)) filters = filters.split(',');
     if (_.contains(filters, '*')) return list;
 
-    let options = filters.reduce(function (options, filter) {
+    const options = filters.reduce(function (options, filter) {
       let type = 'include';
       let value = filter;
 
@@ -38,12 +38,12 @@ function propFilter(prop) {
     }, {});
 
     return list.filter(function (item) {
-      let value = item[prop];
+      const value = item[prop];
 
-      let excluded = options.exclude && _.contains(options.exclude, value);
+      const excluded = options.exclude && _.contains(options.exclude, value);
       if (excluded) return false;
 
-      let included = !options.include || _.contains(options.include, value);
+      const included = !options.include || _.contains(options.include, value);
       if (included) return true;
 
       return false;
diff --git a/src/ui/public/filters/comma_list.js b/src/ui/public/filters/comma_list.js
index febe90384585f..2b5943dae3100 100644
--- a/src/ui/public/filters/comma_list.js
+++ b/src/ui/public/filters/comma_list.js
@@ -13,12 +13,12 @@ uiModules
    * @return {String}
    */
   return function (input, inclusive) {
-    let list = _.commaSeperatedList(input);
+    const list = _.commaSeperatedList(input);
     if (list.length < 2) {
       return list.join('');
     }
 
-    let conj = inclusive ? ' and ' : ' or ';
+    const conj = inclusive ? ' and ' : ' or ';
     return list.slice(0, -1).join(', ') + conj + _.last(list);
 
   };
diff --git a/src/ui/public/filters/rison.js b/src/ui/public/filters/rison.js
index a41864390dc76..264fef2373a78 100644
--- a/src/ui/public/filters/rison.js
+++ b/src/ui/public/filters/rison.js
@@ -1,6 +1,6 @@
 import rison from 'rison-node';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.filter('rison', function () {
   return function (str) {
diff --git a/src/ui/public/filters/trust_as_html.js b/src/ui/public/filters/trust_as_html.js
index e622294557d33..428a5d82d800c 100644
--- a/src/ui/public/filters/trust_as_html.js
+++ b/src/ui/public/filters/trust_as_html.js
@@ -1,6 +1,6 @@
 import angular from 'angular';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 // Simple filter to allow using ng-bind-html without explicitly calling $sce.trustAsHtml in a controller
 // (See http://goo.gl/mpj9o2)
diff --git a/src/ui/public/filters/unique.js b/src/ui/public/filters/unique.js
index 643ae819f591d..e85087ecb1ba8 100644
--- a/src/ui/public/filters/unique.js
+++ b/src/ui/public/filters/unique.js
@@ -6,7 +6,7 @@ uiModules
   .get('kibana')
   .filter('unique', function () {
     return function (arr) {
-      let list = _.unique(arr);
+      const list = _.unique(arr);
       return list;
     };
   });
diff --git a/src/ui/public/highlight/__tests__/highlight.js b/src/ui/public/highlight/__tests__/highlight.js
index 050cd99d92c27..6c71e73ec12fe 100644
--- a/src/ui/public/highlight/__tests__/highlight.js
+++ b/src/ui/public/highlight/__tests__/highlight.js
@@ -15,7 +15,7 @@ describe('Highlight', function () {
     tags = highlightTags;
   }));
 
-  let text = '' +
+  const text = '' +
     'Bacon ipsum dolor amet pork loin pork cow pig beef chuck ground round shankle sirloin landjaeger kevin ' +
     'venison sausage ribeye tongue. Chicken bacon ball tip pork. Brisket pork capicola spare ribs pastrami rump ' +
     'sirloin, t-bone ham shoulder jerky turducken bresaola. Chicken cow beef picanha. Picanha hamburger alcatra ' +
@@ -28,27 +28,27 @@ describe('Highlight', function () {
   });
 
   it('should highlight a single result', function () {
-    let highlights = [
+    const highlights = [
       tags.pre + 'hamburger' + tags.post + ' alcatra cupim. Salami capicola boudin pork belly shank picanha.'
     ];
-    let result = filter(text, highlights);
+    const result = filter(text, highlights);
     expect(result.indexOf('<mark>hamburger</mark>')).to.be.greaterThan(-1);
     expect(result.split('<mark>hamburger</mark>').length).to.be(text.split('hamburger').length);
   });
 
   it('should highlight multiple results', function () {
-    let highlights = [
+    const highlights = [
       'kevin venison sausage ribeye tongue. ' + tags.pre + 'Chicken' + tags.post + ' bacon ball tip pork. Brisket ' +
       'pork capicola spare ribs pastrami rump sirloin, t-bone ham shoulder jerky turducken bresaola. ' + tags.pre +
       'Chicken' + tags.post + ' cow beef picanha. Picanha'
     ];
-    let result = filter(text, highlights);
+    const result = filter(text, highlights);
     expect(result.indexOf('<mark>Chicken</mark>')).to.be.greaterThan(-1);
     expect(result.split('<mark>Chicken</mark>').length).to.be(text.split('Chicken').length);
   });
 
   it('should highlight multiple hits in a result', function () {
-    let highlights = [
+    const highlights = [
       'Bacon ipsum dolor amet ' + tags.pre + 'pork' + tags.post + ' loin ' +
         '' + tags.pre + 'pork' + tags.post + ' cow pig beef chuck ground round shankle ' +
         'sirloin landjaeger',
@@ -58,14 +58,14 @@ describe('Highlight', function () {
       'hamburger alcatra cupim. Salami capicola boudin ' + tags.pre + 'pork' + tags.post + ' ' +
         'belly shank picanha.'
     ];
-    let result = filter(text, highlights);
+    const result = filter(text, highlights);
     expect(result.indexOf('<mark>pork</mark>')).to.be.greaterThan(-1);
     expect(result.split('<mark>pork</mark>').length).to.be(text.split('pork').length);
   });
 
   it('should accept an object and return a string containing its properties', function () {
-    let obj = {foo: 1, bar: 2};
-    let result = filter(obj, null);
+    const obj = {foo: 1, bar: 2};
+    const result = filter(obj, null);
     expect(result.indexOf('' + obj)).to.be(-1);
     expect(result.indexOf('foo')).to.be.greaterThan(-1);
     expect(result.indexOf('bar')).to.be.greaterThan(-1);
diff --git a/src/ui/public/highlight/highlight.js b/src/ui/public/highlight/highlight.js
index f51a3ae2bfb52..e75d433e8a6d1 100644
--- a/src/ui/public/highlight/highlight.js
+++ b/src/ui/public/highlight/highlight.js
@@ -3,7 +3,7 @@ import _ from 'lodash';
 import angular from 'angular';
 import uiModules from 'ui/modules';
 
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.filter('highlight', function (highlightTags) {
   return function (formatted, highlight) {
@@ -13,12 +13,12 @@ module.filter('highlight', function (highlightTags) {
       section = _.escape(section);
 
       // Strip out the highlight tags to compare against the formatted string
-      let untagged = section
+      const untagged = section
         .split(highlightTags.pre).join('')
         .split(highlightTags.post).join('');
 
       // Replace all highlight tags with proper html tags
-      let tagged = section
+      const tagged = section
         .split(highlightTags.pre).join('<mark>')
         .split(highlightTags.post).join('</mark>');
 
diff --git a/src/ui/public/highlight/highlight_tags.js b/src/ui/public/highlight/highlight_tags.js
index 350357ec35b59..19e8a26c43a12 100644
--- a/src/ui/public/highlight/highlight_tags.js
+++ b/src/ui/public/highlight/highlight_tags.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 // By default, ElasticSearch surrounds matched values in <em></em>. This is not ideal because it is possible that
 // the value could contain <em></em> in the value. We define these custom tags that we would never expect to see
diff --git a/src/ui/public/index_patterns/__tests__/_cast_mapping_type.js b/src/ui/public/index_patterns/__tests__/_cast_mapping_type.js
index 60a4b93ba6d77..773f2970fad7f 100644
--- a/src/ui/public/index_patterns/__tests__/_cast_mapping_type.js
+++ b/src/ui/public/index_patterns/__tests__/_cast_mapping_type.js
@@ -20,7 +20,7 @@ describe('type normalizer (castMappingType)', function () {
   });
 
   it('should cast numeric types to "number"', function () {
-    let types = [
+    const types = [
       'float',
       'double',
       'integer',
@@ -36,7 +36,7 @@ describe('type normalizer (castMappingType)', function () {
   });
 
   it('should treat non-numeric known types as what they are', function () {
-    let types = [
+    const types = [
       'date',
       'boolean',
       'ip',
@@ -53,7 +53,7 @@ describe('type normalizer (castMappingType)', function () {
   });
 
   it('should cast text and keyword types to "string"', function () {
-    let types = [
+    const types = [
       'keyword',
       'text'
     ];
diff --git a/src/ui/public/index_patterns/__tests__/_field_format.js b/src/ui/public/index_patterns/__tests__/_field_format.js
index fd8eb22e9dd97..ca8fb8d90fcdf 100644
--- a/src/ui/public/index_patterns/__tests__/_field_format.js
+++ b/src/ui/public/index_patterns/__tests__/_field_format.js
@@ -24,14 +24,14 @@ describe('FieldFormat class', function () {
 
   describe('params', function () {
     it('accepts its params via the constructor', function () {
-      let f = new TestFormat({ foo: 'bar' });
+      const f = new TestFormat({ foo: 'bar' });
       expect(f.param('foo')).to.be('bar');
     });
 
     it('allows reading a clone of the params', function () {
-      let params = { foo: 'bar' };
-      let f = new TestFormat(params);
-      let output = f.params();
+      const params = { foo: 'bar' };
+      const f = new TestFormat(params);
+      const output = f.params();
       expect(output).to.eql(params);
       expect(output).to.not.be(params);
     });
@@ -39,29 +39,29 @@ describe('FieldFormat class', function () {
 
   describe('type', function () {
     it('links the constructor class to instances as the `type`', function () {
-      let f = new TestFormat();
+      const f = new TestFormat();
       expect(f.type).to.be(TestFormat);
     });
   });
 
   describe('toJSON', function () {
     it('serializes to a version a basic id and param pair', function () {
-      let f = new TestFormat({ foo: 'bar' });
-      let ser = JSON.parse(JSON.stringify(f));
+      const f = new TestFormat({ foo: 'bar' });
+      const ser = JSON.parse(JSON.stringify(f));
       expect(ser).to.eql({ id: 'test-format', params: { foo: 'bar' } });
     });
 
     it('removes param values that match the defaults', function () {
       TestFormat.paramDefaults = { foo: 'bar' };
 
-      let f = new TestFormat({ foo: 'bar', baz: 'bar' });
-      let ser = JSON.parse(JSON.stringify(f));
+      const f = new TestFormat({ foo: 'bar', baz: 'bar' });
+      const ser = JSON.parse(JSON.stringify(f));
       expect(ser.params).to.eql({ baz: 'bar' });
     });
 
     it('removes the params entirely if they are empty', function () {
-      let f = new TestFormat();
-      let ser = JSON.parse(JSON.stringify(f));
+      const f = new TestFormat();
+      const ser = JSON.parse(JSON.stringify(f));
       expect(ser).to.not.have.property('params');
     });
   });
@@ -69,7 +69,7 @@ describe('FieldFormat class', function () {
   describe('converters', function () {
     describe('#getConverterFor', function () {
       it('returns a converter for a specific content type', function () {
-        let f = new TestFormat();
+        const f = new TestFormat();
         expect(f.getConverterFor('html')()).to.be.a('string');
         expect(f.getConverterFor('text')()).to.be.a('string');
       });
@@ -81,9 +81,9 @@ describe('FieldFormat class', function () {
           return 'formatted';
         };
 
-        let f = new TestFormat();
-        let text = f.getConverterFor('text');
-        let html = f.getConverterFor('html');
+        const f = new TestFormat();
+        const text = f.getConverterFor('text');
+        const html = f.getConverterFor('html');
         expect(text).to.not.be(html);
         expect(text('formatted')).to.be('formatted');
         expect(html('formatted')).to.be('formatted');
@@ -95,9 +95,9 @@ describe('FieldFormat class', function () {
           html: _.constant('formatted html'),
         };
 
-        let f = new TestFormat();
-        let text = f.getConverterFor('text');
-        let html = f.getConverterFor('html');
+        const f = new TestFormat();
+        const text = f.getConverterFor('text');
+        const html = f.getConverterFor('html');
         expect(text).to.not.be(html);
         expect(text('formatted text')).to.be('formatted text');
         expect(html('formatted html')).to.be('formatted html');
@@ -105,13 +105,13 @@ describe('FieldFormat class', function () {
 
       it('does not escape the output of the text converter', function () {
         TestFormat.prototype._convert = _.constant('<script>alert("xxs");</script>');
-        let f = new TestFormat();
+        const f = new TestFormat();
         expect(f.convert('', 'text')).to.contain('<');
       });
 
       it('does escape the output of the text converter if used in an html context', function () {
         TestFormat.prototype._convert = _.constant('<script>alert("xxs");</script>');
-        let f = new TestFormat();
+        const f = new TestFormat();
         expect(f.convert('', 'html')).to.not.contain('<');
       });
 
@@ -121,7 +121,7 @@ describe('FieldFormat class', function () {
           html: _.constant('<img>'),
         };
 
-        let f = new TestFormat();
+        const f = new TestFormat();
         expect(f.convert('', 'text')).to.be('<img>');
         expect(f.convert('', 'html')).to.be('<img>');
       });
@@ -134,7 +134,7 @@ describe('FieldFormat class', function () {
           html: _.constant('html'),
         };
 
-        let f = new TestFormat();
+        const f = new TestFormat();
         expect(f.convert('val')).to.be('text');
       });
 
@@ -144,12 +144,12 @@ describe('FieldFormat class', function () {
           html: _.constant('html'),
         };
 
-        let f = new TestFormat();
+        const f = new TestFormat();
         expect(f.convert('val', 'html')).to.be('html');
       });
 
       it('formats a value as " - " when no value is specified', function () {
-        let f = new TestFormat();
+        const f = new TestFormat();
         expect(f.convert()).to.be(' - ');
       });
     });
diff --git a/src/ui/public/index_patterns/__tests__/_index_pattern.js b/src/ui/public/index_patterns/__tests__/_index_pattern.js
index 9503deeb9e446..fda66d2d3c7f1 100644
--- a/src/ui/public/index_patterns/__tests__/_index_pattern.js
+++ b/src/ui/public/index_patterns/__tests__/_index_pattern.js
@@ -21,7 +21,7 @@ describe('index pattern', function () {
   let DocSource;
   let config;
   let docSourceResponse;
-  let indexPatternId = 'test-pattern';
+  const indexPatternId = 'test-pattern';
   let indexPattern;
   let calculateIndices;
   let $rootScope;
diff --git a/src/ui/public/index_patterns/__tests__/_map_field.js b/src/ui/public/index_patterns/__tests__/_map_field.js
index 3384e9c530a7c..4832d85a354d6 100644
--- a/src/ui/public/index_patterns/__tests__/_map_field.js
+++ b/src/ui/public/index_patterns/__tests__/_map_field.js
@@ -18,25 +18,25 @@ describe('field mapping normalizer (mapField)', function () {
   });
 
   it('should return a modified copy of the object, not modify the original', function () {
-    let pristine = _.cloneDeep(fields['foo.bar']);
-    let mapped = fn(fields['foo.bar'], 'foo.bar');
+    const pristine = _.cloneDeep(fields['foo.bar']);
+    const mapped = fn(fields['foo.bar'], 'foo.bar');
 
     expect(fields['foo.bar']).to.not.eql(mapped);
     expect(fields['foo.bar']).to.eql(pristine);
   });
 
   it('should not consider _id indexed unless it is', function () {
-    let mapped = fn(fields._id, '_id');
+    const mapped = fn(fields._id, '_id');
     expect(mapped.indexed).to.be(false);
 
-    let mapping = _.cloneDeep(fields._id);
+    const mapping = _.cloneDeep(fields._id);
     mapping.mapping._id.index = 'not_analyzed';
-    let mapped2 = fn(mapping, '_id');
+    const mapped2 = fn(mapping, '_id');
     expect(mapped2.indexed).to.be(true);
   });
 
   it('should always consider _timestamp to be an indexed date', function () {
-    let mapped = fn(fields._timestamp, '_timestamp');
+    const mapped = fn(fields._timestamp, '_timestamp');
     expect(mapped.indexed).to.be(true);
     expect(mapped.type).to.be('date');
   });
@@ -51,7 +51,7 @@ describe('field mapping normalizer (mapField)', function () {
   });
 
   it('should treat other values for index as true', function () {
-    let mapped = fn(fields.not_analyzed_field, 'not_analyzed_field');
+    const mapped = fn(fields.not_analyzed_field, 'not_analyzed_field');
     expect(mapped.indexed).to.be(true);
   });
 
diff --git a/src/ui/public/index_patterns/__tests__/_pattern_to_wildcard.js b/src/ui/public/index_patterns/__tests__/_pattern_to_wildcard.js
index e2313bce95759..39f688a74fa7a 100644
--- a/src/ui/public/index_patterns/__tests__/_pattern_to_wildcard.js
+++ b/src/ui/public/index_patterns/__tests__/_pattern_to_wildcard.js
@@ -1,7 +1,7 @@
 import expect from 'expect.js';
 describe('Index pattern to wildcard', function () {
 
-  let fn = require('ui/index_patterns/_pattern_to_wildcard')();
+  const fn = require('ui/index_patterns/_pattern_to_wildcard')();
 
 
   it('should be a function', function () {
diff --git a/src/ui/public/index_patterns/__tests__/flatten_hit.js b/src/ui/public/index_patterns/__tests__/flatten_hit.js
index 632e959b263cc..882d44fafa655 100644
--- a/src/ui/public/index_patterns/__tests__/flatten_hit.js
+++ b/src/ui/public/index_patterns/__tests__/flatten_hit.js
@@ -13,7 +13,7 @@ describe('IndexPattern#flattenHit()', function () {
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function (Private, $injector) {
-    let indexPattern = {
+    const indexPattern = {
       fields: {
         byName: {
           'message': { type: 'string' },
diff --git a/src/ui/public/index_patterns/__tests__/intervals.js b/src/ui/public/index_patterns/__tests__/intervals.js
index ff486c86a68c4..78b8e082dd249 100644
--- a/src/ui/public/index_patterns/__tests__/intervals.js
+++ b/src/ui/public/index_patterns/__tests__/intervals.js
@@ -14,10 +14,10 @@ describe('Index Patterns', function () {
     }));
 
     it('should return correct indices for hourly [logstash-]YYYY.MM.DD.HH', function () {
-      let start = moment.utc('2014-01-01T07:00:00Z');
-      let end = moment.utc('2014-01-01T08:30:00Z');
-      let interval = { name: 'hours', startOf: 'hour', display: 'Hourly' };
-      let list = intervals.toIndexList('[logstash-]YYYY.MM.DD.HH', interval, start, end);
+      const start = moment.utc('2014-01-01T07:00:00Z');
+      const end = moment.utc('2014-01-01T08:30:00Z');
+      const interval = { name: 'hours', startOf: 'hour', display: 'Hourly' };
+      const list = intervals.toIndexList('[logstash-]YYYY.MM.DD.HH', interval, start, end);
       expect(list).to.eql([
         {
           index: 'logstash-2014.01.01.07',
@@ -33,10 +33,10 @@ describe('Index Patterns', function () {
     });
 
     it('should return correct indices for daily [logstash-]YYYY.MM.DD', function () {
-      let start = moment(1418244231248);
-      let end = moment(1418849261281);
-      let interval = { name: 'days', startOf: 'day', display: 'Daily' };
-      let list = intervals.toIndexList('[logstash-]YYYY.MM.DD', interval, start, end);
+      const start = moment(1418244231248);
+      const end = moment(1418849261281);
+      const interval = { name: 'days', startOf: 'day', display: 'Daily' };
+      const list = intervals.toIndexList('[logstash-]YYYY.MM.DD', interval, start, end);
       expect(list).to.eql([
         {
           index: 'logstash-2014.12.10',
@@ -82,10 +82,10 @@ describe('Index Patterns', function () {
     });
 
     it('should return correct indices for monthly [logstash-]YYYY.MM', function () {
-      let start = moment.utc('2014-12-01');
-      let end = moment.utc('2015-02-01');
-      let interval = { name: 'months', startOf: 'month', display: 'Monthly' };
-      let list = intervals.toIndexList('[logstash-]YYYY.MM', interval, start, end);
+      const start = moment.utc('2014-12-01');
+      const end = moment.utc('2015-02-01');
+      const interval = { name: 'months', startOf: 'month', display: 'Monthly' };
+      const list = intervals.toIndexList('[logstash-]YYYY.MM', interval, start, end);
       expect(list).to.eql([
         {
           index: 'logstash-2014.12',
@@ -106,10 +106,10 @@ describe('Index Patterns', function () {
     });
 
     it('should return correct indices for yearly [logstash-]YYYY', function () {
-      let start = moment.utc('2014-12-01');
-      let end = moment.utc('2015-02-01');
-      let interval = { name: 'years', startOf: 'year', display: 'Yearly' };
-      let list = intervals.toIndexList('[logstash-]YYYY', interval, start, end);
+      const start = moment.utc('2014-12-01');
+      const end = moment.utc('2015-02-01');
+      const interval = { name: 'years', startOf: 'year', display: 'Yearly' };
+      const list = intervals.toIndexList('[logstash-]YYYY', interval, start, end);
       expect(list).to.eql([
         {
           index: 'logstash-2014',
@@ -126,10 +126,10 @@ describe('Index Patterns', function () {
 
     context('with sortDirection=asc', function () {
       it('returns values in ascending order', function () {
-        let start = moment.utc('2014-12-01');
-        let end = moment.utc('2015-02-01');
-        let interval = { name: 'years', startOf: 'year', display: 'Yearly' };
-        let list = intervals.toIndexList('[logstash-]YYYY', interval, start, end, 'asc');
+        const start = moment.utc('2014-12-01');
+        const end = moment.utc('2015-02-01');
+        const interval = { name: 'years', startOf: 'year', display: 'Yearly' };
+        const list = intervals.toIndexList('[logstash-]YYYY', interval, start, end, 'asc');
         expect(list).to.eql([
           {
             index: 'logstash-2014',
@@ -147,10 +147,10 @@ describe('Index Patterns', function () {
 
     context('with sortDirection=desc', function () {
       it('returns values in descending order', function () {
-        let start = moment.utc('2014-12-01');
-        let end = moment.utc('2015-02-01');
-        let interval = { name: 'years', startOf: 'year', display: 'Yearly' };
-        let list = intervals.toIndexList('[logstash-]YYYY', interval, start, end, 'desc');
+        const start = moment.utc('2014-12-01');
+        const end = moment.utc('2015-02-01');
+        const interval = { name: 'years', startOf: 'year', display: 'Yearly' };
+        const list = intervals.toIndexList('[logstash-]YYYY', interval, start, end, 'desc');
         expect(list).to.eql([
           {
             index: 'logstash-2015',
diff --git a/src/ui/public/index_patterns/_cast_mapping_type.js b/src/ui/public/index_patterns/_cast_mapping_type.js
index bfeab98c2a171..93f36b18bffc1 100644
--- a/src/ui/public/index_patterns/_cast_mapping_type.js
+++ b/src/ui/public/index_patterns/_cast_mapping_type.js
@@ -36,7 +36,7 @@ export default function CastMappingTypeFn() {
   function castMappingType(name) {
     if (!name) return 'unknown';
 
-    let match = castMappingType.types.byName[name];
+    const match = castMappingType.types.byName[name];
     return match ? match.type : 'string';
   }
 
diff --git a/src/ui/public/index_patterns/_ensure_some.js b/src/ui/public/index_patterns/_ensure_some.js
index 8576b4fff4cd2..ffe6be42eed04 100644
--- a/src/ui/public/index_patterns/_ensure_some.js
+++ b/src/ui/public/index_patterns/_ensure_some.js
@@ -1,6 +1,6 @@
 import errors from 'ui/errors';
 export default function EnsureSomeIndexPatternsFn(Private, Notifier, $location, kbnUrl) {
-  let notify = new Notifier();
+  const notify = new Notifier();
 
   return function ensureSomeIndexPatterns() {
     return function promiseHandler(patterns) {
diff --git a/src/ui/public/index_patterns/_field.js b/src/ui/public/index_patterns/_field.js
index af4471f48feef..2edde66a1194b 100644
--- a/src/ui/public/index_patterns/_field.js
+++ b/src/ui/public/index_patterns/_field.js
@@ -3,10 +3,10 @@ import IndexPatternsFieldFormatFieldFormatProvider from 'ui/index_patterns/_fiel
 import IndexPatternsFieldTypesProvider from 'ui/index_patterns/_field_types';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function FieldObjectProvider(Private, shortDotsFilter, $rootScope, Notifier) {
-  let notify = new Notifier({ location: 'IndexPattern Field' });
-  let FieldFormat = Private(IndexPatternsFieldFormatFieldFormatProvider);
-  let fieldTypes = Private(IndexPatternsFieldTypesProvider);
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const notify = new Notifier({ location: 'IndexPattern Field' });
+  const FieldFormat = Private(IndexPatternsFieldFormatFieldFormatProvider);
+  const fieldTypes = Private(IndexPatternsFieldTypesProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   function Field(indexPattern, spec) {
     // unwrap old instances of Field
@@ -15,7 +15,7 @@ export default function FieldObjectProvider(Private, shortDotsFilter, $rootScope
     // constuct this object using ObjDefine class, which
     // extends the Field.prototype but gets it's properties
     // defined using the logic below
-    let obj = new ObjDefine(spec, Field.prototype);
+    const obj = new ObjDefine(spec, Field.prototype);
 
     if (spec.name === '_source') {
       spec.type = '_source';
@@ -38,10 +38,10 @@ export default function FieldObjectProvider(Private, shortDotsFilter, $rootScope
       format = indexPattern.fieldFormatMap[spec.name] || fieldFormats.getDefaultInstance(spec.type);
     }
 
-    let indexed = !!spec.indexed;
-    let scripted = !!spec.scripted;
-    let sortable = spec.name === '_score' || ((indexed || scripted) && type.sortable);
-    let filterable = spec.name === '_id' || scripted || (indexed && type.filterable);
+    const indexed = !!spec.indexed;
+    const scripted = !!spec.scripted;
+    const sortable = spec.name === '_score' || ((indexed || scripted) && type.sortable);
+    const filterable = spec.name === '_id' || scripted || (indexed && type.filterable);
 
     obj.fact('name');
     obj.fact('type');
diff --git a/src/ui/public/index_patterns/_field_format/content_types.js b/src/ui/public/index_patterns/_field_format/content_types.js
index ed82f0210c1f0..c19edabe35669 100644
--- a/src/ui/public/index_patterns/_field_format/content_types.js
+++ b/src/ui/public/index_patterns/_field_format/content_types.js
@@ -3,7 +3,7 @@ import angular from 'angular';
 import 'ui/highlight';
 export default function contentTypesProvider(highlightFilter) {
 
-  let types = {
+  const types = {
     html: function (format, convert) {
       return function recurse(value, field, hit) {
         if (value == null) {
@@ -14,10 +14,10 @@ export default function contentTypesProvider(highlightFilter) {
           return convert.call(format, value, field, hit);
         }
 
-        let subVals = value.map(function (v) {
+        const subVals = value.map(function (v) {
           return recurse(v, field, hit);
         });
-        let useMultiLine = subVals.some(function (sub) {
+        const useMultiLine = subVals.some(function (sub) {
           return sub.indexOf('\n') > -1;
         });
 
@@ -42,7 +42,7 @@ export default function contentTypesProvider(highlightFilter) {
   }
 
   function fallbackHtml(value, field, hit) {
-    let formatted = _.escape(this.convert(value, 'text'));
+    const formatted = _.escape(this.convert(value, 'text'));
 
     if (!hit || !hit.highlight || !hit.highlight[field.name]) {
       return formatted;
@@ -52,8 +52,8 @@ export default function contentTypesProvider(highlightFilter) {
   }
 
   function setup(format) {
-    let src = format._convert || {};
-    let converters = format._convert = {};
+    const src = format._convert || {};
+    const converters = format._convert = {};
 
     converters.text = types.text(format, src.text || fallbackText);
     converters.html = types.html(format, src.html || fallbackHtml);
diff --git a/src/ui/public/index_patterns/_field_format/field_format.js b/src/ui/public/index_patterns/_field_format/field_format.js
index 53b48c69985bd..0084cea0477cd 100644
--- a/src/ui/public/index_patterns/_field_format/field_format.js
+++ b/src/ui/public/index_patterns/_field_format/field_format.js
@@ -1,10 +1,10 @@
 import _ from 'lodash';
 import IndexPatternsFieldFormatContentTypesProvider from 'ui/index_patterns/_field_format/content_types';
 export default function FieldFormatClassProvider(config, $rootScope, Private) {
-  let contentTypes = Private(IndexPatternsFieldFormatContentTypesProvider);
+  const contentTypes = Private(IndexPatternsFieldFormatContentTypesProvider);
 
   function FieldFormat(params) {
-    let self = this;
+    const self = this;
 
     // give the constructor a more appropriate name
     self.type = self.constructor;
@@ -59,7 +59,7 @@ export default function FieldFormatClassProvider(config, $rootScope, Private) {
    * @return {any}
    */
   FieldFormat.prototype.param = function (name) {
-    let val = this._params[name];
+    const val = this._params[name];
     if (val || val === false || val === 0) {
       // truthy, false, or 0 are fine
       // '', NaN, null, undefined, etc are not
@@ -84,8 +84,8 @@ export default function FieldFormatClassProvider(config, $rootScope, Private) {
    * @return {object}
    */
   FieldFormat.prototype.toJSON = function () {
-    let type = this.type;
-    let defaults = this._paramDefaults;
+    const type = this.type;
+    const defaults = this._paramDefaults;
 
     let params = _.transform(this._params, function (uniqParams, val, param) {
       if (val !== defaults[param]) {
diff --git a/src/ui/public/index_patterns/_field_list.js b/src/ui/public/index_patterns/_field_list.js
index 438159f334de6..ddfc65ff042a5 100644
--- a/src/ui/public/index_patterns/_field_list.js
+++ b/src/ui/public/index_patterns/_field_list.js
@@ -2,7 +2,7 @@ import IndexedArray from 'ui/indexed_array';
 import _ from 'lodash';
 import IndexPatternsFieldProvider from 'ui/index_patterns/_field';
 export default function FieldListProvider(Private) {
-  let Field = Private(IndexPatternsFieldProvider);
+  const Field = Private(IndexPatternsFieldProvider);
 
   _.class(FieldList).inherits(IndexedArray);
   function FieldList(indexPattern, specs) {
diff --git a/src/ui/public/index_patterns/_flatten_hit.js b/src/ui/public/index_patterns/_flatten_hit.js
index 7d137cfd070e6..c757789885138 100644
--- a/src/ui/public/index_patterns/_flatten_hit.js
+++ b/src/ui/public/index_patterns/_flatten_hit.js
@@ -9,10 +9,10 @@ export default function FlattenHitProvider(config) {
   });
 
   function flattenHit(indexPattern, hit) {
-    let flat = {};
+    const flat = {};
 
     // recursively merge _source
-    let fields = indexPattern.fields.byName;
+    const fields = indexPattern.fields.byName;
     (function flatten(obj, keyPrefix) {
       keyPrefix = keyPrefix ? keyPrefix + '.' : '';
       _.forOwn(obj, function (val, key) {
@@ -20,8 +20,8 @@ export default function FlattenHitProvider(config) {
 
         if (flat[key] !== void 0) return;
 
-        let hasValidMapping = (fields[key] && fields[key].type !== 'conflict');
-        let isValue = !_.isPlainObject(val);
+        const hasValidMapping = (fields[key] && fields[key].type !== 'conflict');
+        const isValue = !_.isPlainObject(val);
 
         if (hasValidMapping || isValue) {
           flat[key] = val;
diff --git a/src/ui/public/index_patterns/_format_hit.js b/src/ui/public/index_patterns/_format_hit.js
index d188952f33532..6f705da8b77b4 100644
--- a/src/ui/public/index_patterns/_format_hit.js
+++ b/src/ui/public/index_patterns/_format_hit.js
@@ -5,7 +5,7 @@ import _ from 'lodash';
 export default function (indexPattern, defaultFormat) {
 
   function convert(hit, val, fieldName) {
-    let field = indexPattern.fields.byName[fieldName];
+    const field = indexPattern.fields.byName[fieldName];
     if (!field) return defaultFormat.convert(val, 'html');
     return field.format.getConverterFor('html')(val, field, hit);
   }
@@ -15,12 +15,12 @@ export default function (indexPattern, defaultFormat) {
 
     // use and update the partial cache, but don't rewrite it. _source is stored in partials
     // but not $$_formatted
-    let partials = hit.$$_partialFormatted || (hit.$$_partialFormatted = {});
-    let cache = hit.$$_formatted = {};
+    const partials = hit.$$_partialFormatted || (hit.$$_partialFormatted = {});
+    const cache = hit.$$_formatted = {};
 
     _.forOwn(indexPattern.flattenHit(hit), function (val, fieldName) {
       // sync the formatted and partial cache
-      let formatted = partials[fieldName] == null ? convert(hit, val, fieldName) : partials[fieldName];
+      const formatted = partials[fieldName] == null ? convert(hit, val, fieldName) : partials[fieldName];
       cache[fieldName] = partials[fieldName] = formatted;
     });
 
@@ -37,7 +37,7 @@ export default function (indexPattern, defaultFormat) {
       partials = hit.$$_partialFormatted = {};
     }
 
-    let val = fieldName === '_source' ? hit._source : indexPattern.flattenHit(hit)[fieldName];
+    const val = fieldName === '_source' ? hit._source : indexPattern.flattenHit(hit)[fieldName];
     return partials[fieldName] = convert(hit, val, fieldName);
   };
 
diff --git a/src/ui/public/index_patterns/_get_computed_fields.js b/src/ui/public/index_patterns/_get_computed_fields.js
index 8730183a60066..e5bb687fded3c 100644
--- a/src/ui/public/index_patterns/_get_computed_fields.js
+++ b/src/ui/public/index_patterns/_get_computed_fields.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 // Takes a hit, merges it with any stored/scripted fields, and with the metaFields
 // returns a flattened version
 export default function () {
-  let self = this;
-  let scriptFields = {};
+  const self = this;
+  const scriptFields = {};
   let docvalueFields = [];
 
   docvalueFields = _.pluck(self.fields.byType.date, 'name');
diff --git a/src/ui/public/index_patterns/_get_ids.js b/src/ui/public/index_patterns/_get_ids.js
index b499b1dd3859d..969e186a4fb4e 100644
--- a/src/ui/public/index_patterns/_get_ids.js
+++ b/src/ui/public/index_patterns/_get_ids.js
@@ -5,7 +5,7 @@ export default function GetIndexPatternIdsFn(es, kbnIndex) {
   // didn't incorportate with the indexPattern cache to prevent id collisions.
   let cachedPromise;
 
-  let getIds = function () {
+  const getIds = function () {
     if (cachedPromise) {
       // retrun a clone of the cached response
       return cachedPromise.then(function (cachedResp) {
diff --git a/src/ui/public/index_patterns/_intervals.js b/src/ui/public/index_patterns/_intervals.js
index 89617306db719..8fe028348be19 100644
--- a/src/ui/public/index_patterns/_intervals.js
+++ b/src/ui/public/index_patterns/_intervals.js
@@ -3,7 +3,7 @@ import moment from 'moment';
 import IndexedArray from 'ui/indexed_array';
 export default function IndexNameIntervalsService(timefilter) {
 
-  let intervals = new IndexedArray({
+  const intervals = new IndexedArray({
     index: ['name'],
     initialSet: [
       {
@@ -40,10 +40,10 @@ export default function IndexNameIntervalsService(timefilter) {
     // setup the range that the list will span, return two moment objects that
     // are in proper order. a and b can be numbers to specify to go before or after now (respectively)
     // a certain number of times, based on the interval
-    let range = [[a, 'min', 'startOf'], [b, 'max', 'startOf']].map(function (v) {
+    const range = [[a, 'min', 'startOf'], [b, 'max', 'startOf']].map(function (v) {
       let val = v[0];
-      let bound = v[1];
-      let extend = v[2];
+      const bound = v[1];
+      const extend = v[2];
 
       // grab a bound from the time filter
       if (val == null) {
@@ -64,12 +64,12 @@ export default function IndexNameIntervalsService(timefilter) {
       if (!interval) throw new Error('Interval must be one of ' + _.pluck(intervals, 'name'));
     }
 
-    let indexList = [];
+    const indexList = [];
     let start = range.shift();
     // turn stop into milliseconds to that it's not constantly converted by the while condition
-    let stop = range.shift().valueOf();
+    const stop = range.shift().valueOf();
 
-    let add = sortDirection === 'desc' ? 'unshift' : 'push';
+    const add = sortDirection === 'desc' ? 'unshift' : 'push';
 
     while (start <= stop) {
       const index = start.format(format);
diff --git a/src/ui/public/index_patterns/_local_cache.js b/src/ui/public/index_patterns/_local_cache.js
index 64ec26847600a..52a7079f581b2 100644
--- a/src/ui/public/index_patterns/_local_cache.js
+++ b/src/ui/public/index_patterns/_local_cache.js
@@ -4,17 +4,17 @@ import angular from 'angular';
 export default function LocalCacheFactory() {
   function LocalCache(opts) {
     opts = opts || {};
-    let _id = opts.id || function (o) { return '' + o; };
+    const _id = opts.id || function (o) { return '' + o; };
     let _cache = {};
 
     this.get = function (obj) {
-      let id = _id(obj);
+      const id = _id(obj);
       return _cache[id] ? JSON.parse(_cache[id]) : null;
     };
 
     this.set = function (obj, val) {
-      let id = _id(obj);
-      let clean = !_cache.hasOwnProperty(id);
+      const id = _id(obj);
+      const clean = !_cache.hasOwnProperty(id);
       _cache[id] = angular.toJson(val);
       return clean;
     };
@@ -25,7 +25,7 @@ export default function LocalCacheFactory() {
         return;
       }
 
-      let id = _id(obj);
+      const id = _id(obj);
       delete _cache[id];
     };
   }
diff --git a/src/ui/public/index_patterns/_map_field.js b/src/ui/public/index_patterns/_map_field.js
index b4d3a4aa42f78..08a8ca55c10cc 100644
--- a/src/ui/public/index_patterns/_map_field.js
+++ b/src/ui/public/index_patterns/_map_field.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import IndexPatternsCastMappingTypeProvider from 'ui/index_patterns/_cast_mapping_type';
 export default function MapFieldFn(Private, config) {
-  let castMappingType = Private(IndexPatternsCastMappingTypeProvider);
+  const castMappingType = Private(IndexPatternsCastMappingTypeProvider);
 
   /**
    * Accepts a field object and its name, and tries to give it a mapping
@@ -10,11 +10,11 @@ export default function MapFieldFn(Private, config) {
    * @return {Object} - the resulting field after overrides and tweaking
    */
   return function mapField(field, name) {
-    let keys = Object.keys(field.mapping);
+    const keys = Object.keys(field.mapping);
     if (keys.length === 0 || (name[0] === '_') && !_.contains(config.get('metaFields'), name)) return;
 
     // Override the mapping, even if elasticsearch says otherwise
-    let mappingOverrides = {
+    const mappingOverrides = {
       _source: { type: '_source' },
       _index: { type: 'string' },
       _type: { type: 'string' },
@@ -29,7 +29,7 @@ export default function MapFieldFn(Private, config) {
       }
     };
 
-    let mapping = _.cloneDeep(field.mapping[keys.shift()]);
+    const mapping = _.cloneDeep(field.mapping[keys.shift()]);
 
     if (!mapping.index || mapping.index === 'no') {
       // elasticsearch responds with false sometimes and 'no' others
diff --git a/src/ui/public/index_patterns/_mapper.js b/src/ui/public/index_patterns/_mapper.js
index 0ee8984327749..983f86e7a716d 100644
--- a/src/ui/public/index_patterns/_mapper.js
+++ b/src/ui/public/index_patterns/_mapper.js
@@ -7,19 +7,19 @@ import IndexPatternsPatternToWildcardProvider from 'ui/index_patterns/_pattern_t
 import IndexPatternsLocalCacheProvider from 'ui/index_patterns/_local_cache';
 export default function MapperService(Private, Promise, es, config, kbnIndex) {
 
-  let transformMappingIntoFields = Private(IndexPatternsTransformMappingIntoFieldsProvider);
-  let intervals = Private(IndexPatternsIntervalsProvider);
-  let patternToWildcard = Private(IndexPatternsPatternToWildcardProvider);
+  const transformMappingIntoFields = Private(IndexPatternsTransformMappingIntoFieldsProvider);
+  const intervals = Private(IndexPatternsIntervalsProvider);
+  const patternToWildcard = Private(IndexPatternsPatternToWildcardProvider);
 
-  let LocalCache = Private(IndexPatternsLocalCacheProvider);
+  const LocalCache = Private(IndexPatternsLocalCacheProvider);
 
   function Mapper() {
 
     // Save a reference to mapper
-    let self = this;
+    const self = this;
 
     // proper-ish cache, keeps a clean copy of the object, only returns copies of it's copy
-    let fieldCache = self.cache = new LocalCache();
+    const fieldCache = self.cache = new LocalCache();
 
     /**
      * Gets an object containing all fields with their mappings
@@ -29,9 +29,9 @@ export default function MapperService(Private, Promise, es, config, kbnIndex) {
      * @async
      */
     self.getFieldsForIndexPattern = function (indexPattern, skipIndexPatternCache) {
-      let id = indexPattern.id;
+      const id = indexPattern.id;
 
-      let cache = fieldCache.get(id);
+      const cache = fieldCache.get(id);
       if (cache) return Promise.resolve(cache);
 
       if (!skipIndexPatternCache) {
@@ -81,7 +81,7 @@ export default function MapperService(Private, Promise, es, config, kbnIndex) {
       })
       .then(function (resp) {
         // let all = Object.keys(resp).sort();
-        let all = _(resp)
+        const all = _(resp)
         .map(function (index, key) {
           if (index.aliases) {
             return [Object.keys(index.aliases), key];
@@ -94,8 +94,8 @@ export default function MapperService(Private, Promise, es, config, kbnIndex) {
         .uniq(true)
         .value();
 
-        let matches = all.filter(function (existingIndex) {
-          let parsed = moment(existingIndex, indexPattern.id);
+        const matches = all.filter(function (existingIndex) {
+          const parsed = moment(existingIndex, indexPattern.id);
           return existingIndex === parsed.format(indexPattern.id);
         });
 
diff --git a/src/ui/public/index_patterns/_pattern_cache.js b/src/ui/public/index_patterns/_pattern_cache.js
index e9f57f5188e0a..7062ddb44bfd4 100644
--- a/src/ui/public/index_patterns/_pattern_cache.js
+++ b/src/ui/public/index_patterns/_pattern_cache.js
@@ -1,9 +1,9 @@
 import _ from 'lodash';
 export default function PatternCache() {
 
-  let vals = {};
+  const vals = {};
 
-  let validId = function (id) {
+  const validId = function (id) {
     return typeof id !== 'object';
   };
 
diff --git a/src/ui/public/index_patterns/_pattern_to_wildcard.js b/src/ui/public/index_patterns/_pattern_to_wildcard.js
index 447af376c807d..0193241ac12ca 100644
--- a/src/ui/public/index_patterns/_pattern_to_wildcard.js
+++ b/src/ui/public/index_patterns/_pattern_to_wildcard.js
@@ -5,7 +5,7 @@ export default function PatternToWildcardFn() {
     let inPattern = false;
 
     for (let i = 0; i < format.length; i++) {
-      let ch = format.charAt(i);
+      const ch = format.charAt(i);
       switch (ch) {
         case '[':
           inPattern = false;
diff --git a/src/ui/public/index_patterns/_transform_mapping_into_fields.js b/src/ui/public/index_patterns/_transform_mapping_into_fields.js
index 059101e76695e..cf9c3d102facb 100644
--- a/src/ui/public/index_patterns/_transform_mapping_into_fields.js
+++ b/src/ui/public/index_patterns/_transform_mapping_into_fields.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import IndexPatternsMapFieldProvider from 'ui/index_patterns/_map_field';
 export default function transformMappingIntoFields(Private, kbnIndex, config) {
-  let mapField = Private(IndexPatternsMapFieldProvider);
+  const mapField = Private(IndexPatternsMapFieldProvider);
 
 
   /**
@@ -14,15 +14,15 @@ export default function transformMappingIntoFields(Private, kbnIndex, config) {
    *                    use-cases
    */
   return function (response) {
-    let fields = {};
+    const fields = {};
     _.each(response, function (index, indexName) {
       if (indexName === kbnIndex) return;
       _.each(index.mappings, function (mappings) {
         _.each(mappings, function (field, name) {
-          let keys = Object.keys(field.mapping);
+          const keys = Object.keys(field.mapping);
           if (keys.length === 0 || (name[0] === '_') && !_.contains(config.get('metaFields'), name)) return;
 
-          let mapping = mapField(field, name);
+          const mapping = mapField(field, name);
 
           if (fields[name]) {
             if (fields[name].type !== mapping.type) {
@@ -39,7 +39,7 @@ export default function transformMappingIntoFields(Private, kbnIndex, config) {
     config.get('metaFields').forEach(function (meta) {
       if (fields[meta]) return;
 
-      let field = { mapping: {} };
+      const field = { mapping: {} };
       field.mapping[meta] = {};
       fields[meta] = mapField(field, meta);
     });
diff --git a/src/ui/public/index_patterns/index_patterns.js b/src/ui/public/index_patterns/index_patterns.js
index 18ea1b7c95cfd..0a366fb8c2e07 100644
--- a/src/ui/public/index_patterns/index_patterns.js
+++ b/src/ui/public/index_patterns/index_patterns.js
@@ -9,20 +9,20 @@ import IndexPatternsMapperProvider from 'ui/index_patterns/_mapper';
 import IndexPatternsPatternToWildcardProvider from 'ui/index_patterns/_pattern_to_wildcard';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana/index_patterns');
+const module = uiModules.get('kibana/index_patterns');
 
 function IndexPatternsProvider(es, Notifier, Private, Promise, kbnIndex) {
-  let self = this;
+  const self = this;
 
-  let IndexPattern = Private(IndexPatternsIndexPatternProvider);
-  let patternCache = Private(IndexPatternsPatternCacheProvider);
+  const IndexPattern = Private(IndexPatternsIndexPatternProvider);
+  const patternCache = Private(IndexPatternsPatternCacheProvider);
 
-  let notify = new Notifier({ location: 'IndexPatterns Service'});
+  const notify = new Notifier({ location: 'IndexPatterns Service'});
 
   self.get = function (id) {
     if (!id) return self.make();
 
-    let cache = patternCache.get(id);
+    const cache = patternCache.get(id);
     return cache || patternCache.set(id, self.make(id));
   };
 
diff --git a/src/ui/public/index_patterns/route_setup/load_default.js b/src/ui/public/index_patterns/route_setup/load_default.js
index 270e163c06c92..d59b1efb498cd 100644
--- a/src/ui/public/index_patterns/route_setup/load_default.js
+++ b/src/ui/public/index_patterns/route_setup/load_default.js
@@ -4,26 +4,26 @@ import { NoDefaultIndexPattern, NoDefinedIndexPatterns } from 'ui/errors';
 import GetIdsProvider from '../_get_ids';
 import CourierDataSourceRootSearchSourceProvider from 'ui/courier/data_source/_root_search_source';
 import uiRoutes from 'ui/routes';
-let notify = new Notifier({
+const notify = new Notifier({
   location: 'Index Patterns'
 });
 
 module.exports = function (opts) {
   opts = opts || {};
-  let whenMissingRedirectTo = opts.whenMissingRedirectTo || null;
+  const whenMissingRedirectTo = opts.whenMissingRedirectTo || null;
   let defaultRequiredToasts = null;
 
   uiRoutes
   .addSetupWork(function loadDefaultIndexPattern(Private, Promise, $route, config, indexPatterns) {
-    let getIds = Private(GetIdsProvider);
-    let rootSearchSource = Private(CourierDataSourceRootSearchSourceProvider);
-    let route = _.get($route, 'current.$$route');
+    const getIds = Private(GetIdsProvider);
+    const rootSearchSource = Private(CourierDataSourceRootSearchSourceProvider);
+    const route = _.get($route, 'current.$$route');
 
     return getIds()
     .then(function (patterns) {
       let defaultId = config.get('defaultIndex');
       let defined = !!defaultId;
-      let exists = _.contains(patterns, defaultId);
+      const exists = _.contains(patterns, defaultId);
 
       if (defined && !exists) {
         config.remove('defaultIndex');
@@ -48,7 +48,7 @@ module.exports = function (opts) {
 
     // failure
     function (err, kbnUrl) {
-      let hasDefault = !(err instanceof NoDefaultIndexPattern);
+      const hasDefault = !(err instanceof NoDefaultIndexPattern);
       if (hasDefault || !whenMissingRedirectTo) throw err; // rethrow
 
       kbnUrl.change(whenMissingRedirectTo);
diff --git a/src/ui/public/indexed_array/__tests__/indexed_array.js b/src/ui/public/indexed_array/__tests__/indexed_array.js
index 69820fbe8bba4..040bc29046a06 100644
--- a/src/ui/public/indexed_array/__tests__/indexed_array.js
+++ b/src/ui/public/indexed_array/__tests__/indexed_array.js
@@ -4,7 +4,7 @@ import expect from 'expect.js';
 import IndexedArray from 'ui/indexed_array';
 
 // this is generally a data-structure that IndexedArray is good for managing
-let users = [
+const users = [
   { name: 'John', id: 69, username: 'beast', group: 'admins' },
   { name: 'Anon', id:  0, username: 'shhhh', group: 'secret' },
   { name: 'Fern', id: 42, username: 'kitty', group: 'editor' },
@@ -43,7 +43,7 @@ describe('IndexedArray', function () {
 
   describe('Indexing', function () {
     it('provides the initial set', function () {
-      let reg = new IndexedArray({
+      const reg = new IndexedArray({
         initialSet: [1, 2, 3]
       });
 
@@ -55,7 +55,7 @@ describe('IndexedArray', function () {
     });
 
     it('indexes the initial set', function () {
-      let reg = new IndexedArray({
+      const reg = new IndexedArray({
         index: ['username'],
         initialSet: users
       });
@@ -66,11 +66,11 @@ describe('IndexedArray', function () {
 
     it('updates indices after values are added', function () {
       // split up the user list, and add it in chunks
-      let firstUser = users.slice(0, 1).pop();
-      let otherUsers = users.slice(1);
+      const firstUser = users.slice(0, 1).pop();
+      const otherUsers = users.slice(1);
 
       // start off with all but the first
-      let reg = new IndexedArray({
+      const reg = new IndexedArray({
         group: ['group'],
         order: ['id'],
         initialSet: otherUsers
@@ -86,7 +86,7 @@ describe('IndexedArray', function () {
 
     it('updates indices after values are removed', function () {
       // start off with all
-      let reg = new IndexedArray({
+      const reg = new IndexedArray({
         group: ['group'],
         order: ['id'],
         initialSet: users
@@ -95,18 +95,18 @@ describe('IndexedArray', function () {
       // remove the last
       reg.pop();
 
-      let expectedCount = users.length - 1;
+      const expectedCount = users.length - 1;
       // indexed lists should be updated
       expect(reg).to.have.length(expectedCount);
 
-      let sumOfGroups = _.reduce(reg.byGroup, function (note, group) {
+      const sumOfGroups = _.reduce(reg.byGroup, function (note, group) {
         return note + group.length;
       }, 0);
       expect(sumOfGroups).to.eql(expectedCount);
     });
 
     it('removes items based on a predicate', function () {
-      let reg = new IndexedArray({
+      const reg = new IndexedArray({
         group: ['group'],
         order: ['id'],
         initialSet: users
@@ -120,7 +120,7 @@ describe('IndexedArray', function () {
     });
 
     it('updates indices after values are re-ordered', function () {
-      let rawUsers = users.slice(0);
+      const rawUsers = users.slice(0);
 
       // collect and shuffle the ids available
       let ids = [];
@@ -128,18 +128,18 @@ describe('IndexedArray', function () {
       ids = _.shuffle(ids);
 
       // move something here
-      let toI = ids.shift();
+      const toI = ids.shift();
       // from here
-      let fromI = ids.shift();
+      const fromI = ids.shift();
       // do the move
-      let move = function (arr) { arr.splice(toI, 0, arr.splice(fromI, 1)[0]); };
+      const move = function (arr) { arr.splice(toI, 0, arr.splice(fromI, 1)[0]); };
 
-      let reg = new IndexedArray({
+      const reg = new IndexedArray({
         index: ['username'],
         initialSet: rawUsers
       });
 
-      let index = reg.byUsername;
+      const index = reg.byUsername;
 
       move(reg);
 
diff --git a/src/ui/public/indexed_array/__tests__/inflector.js b/src/ui/public/indexed_array/__tests__/inflector.js
index 3fc45e1a9f974..e7628ecf159fc 100644
--- a/src/ui/public/indexed_array/__tests__/inflector.js
+++ b/src/ui/public/indexed_array/__tests__/inflector.js
@@ -3,13 +3,13 @@ import expect from 'expect.js';
 
 describe('IndexedArray Inflector', function () {
   it('returns a function', function () {
-    let getter = inflector();
+    const getter = inflector();
     expect(getter).to.be.a('function');
   });
 
   describe('fn', function () {
     it('prepends a prefix', function () {
-      let inflect = inflector('my');
+      const inflect = inflector('my');
 
       expect(inflect('Family')).to.be('myFamily');
       expect(inflect('family')).to.be('myFamily');
@@ -17,7 +17,7 @@ describe('IndexedArray Inflector', function () {
     });
 
     it('adds both a prefix and suffix', function () {
-      let inflect = inflector('foo', 'Bar');
+      const inflect = inflector('foo', 'Bar');
 
       expect(inflect('box')).to.be('fooBoxBar');
       expect(inflect('box.car.MAX')).to.be('fooBoxCarMaxBar');
@@ -25,19 +25,19 @@ describe('IndexedArray Inflector', function () {
     });
 
     it('ignores prefix if it is already at the end of the inflected string', function () {
-      let inflect = inflector('foo', 'Bar');
+      const inflect = inflector('foo', 'Bar');
       expect(inflect('fooBox')).to.be('fooBoxBar');
       expect(inflect('FooBox')).to.be('FooBoxBar');
     });
 
     it('ignores postfix if it is already at the end of the inflected string', function () {
-      let inflect = inflector('foo', 'Bar');
+      const inflect = inflector('foo', 'Bar');
       expect(inflect('bar')).to.be('fooBar');
       expect(inflect('showBoxBar')).to.be('fooShowBoxBar');
     });
 
     it('works with "name"', function () {
-      let inflect = inflector('in', 'Order');
+      const inflect = inflector('in', 'Order');
       expect(inflect('name')).to.be('inNameOrder');
     });
   });
diff --git a/src/ui/public/indexed_array/indexed_array.js b/src/ui/public/indexed_array/indexed_array.js
index 3c7f81fcb52db..3f3325e2d3f7b 100644
--- a/src/ui/public/indexed_array/indexed_array.js
+++ b/src/ui/public/indexed_array/indexed_array.js
@@ -2,12 +2,12 @@ import _ from 'lodash';
 import inflector from 'ui/indexed_array/inflector';
 
 
-let pathGetter = _(_.get).rearg(1, 0).ary(2);
-let inflectIndex = inflector('by');
-let inflectOrder = inflector('in', 'Order');
+const pathGetter = _(_.get).rearg(1, 0).ary(2);
+const inflectIndex = inflector('by');
+const inflectOrder = inflector('in', 'Order');
 
-let CLEAR_CACHE = {};
-let OPT_NAMES = IndexedArray.OPT_NAMES = ['index', 'group', 'order', 'initialSet', 'immutable'];
+const CLEAR_CACHE = {};
+const OPT_NAMES = IndexedArray.OPT_NAMES = ['index', 'group', 'order', 'initialSet', 'immutable'];
 
 /**
  * Generic extension of Array class, which will index (and reindex) the
@@ -69,11 +69,11 @@ IndexedArray.prototype._setupIndices = function (props, inflect, op) {
   // shortcut for empty props
   if (!props || props.length === 0) return;
 
-  let self = this;
+  const self = this;
   return props.map(function (prop) {
 
-    let from = pathGetter.partial(prop).value();
-    let to = inflect(prop);
+    const from = pathGetter.partial(prop).value();
+    const to = inflect(prop);
     let cache;
 
     Object.defineProperty(self, to, {
@@ -105,7 +105,7 @@ IndexedArray.prototype._setupIndices = function (props, inflect, op) {
  * @return {undefined}
  */
 IndexedArray.prototype._clearIndices = function () {
-  let self = this;
+  const self = this;
   self._indexNames.forEach(function (name) {
     self[name] = CLEAR_CACHE;
   });
@@ -120,7 +120,7 @@ IndexedArray.prototype._clearIndices = function () {
  * @return {[type]}        [description]
  */
 'pop push shift splice unshift reverse'.split(' ').forEach(function (method) {
-  let orig = Array.prototype[method];
+  const orig = Array.prototype[method];
 
   IndexedArray.prototype[method] = function (/* args... */) {
     // call the original method with this context
@@ -141,7 +141,7 @@ IndexedArray.prototype._clearIndices = function () {
 * @return {array} - the removed data
 */
 IndexedArray.prototype.remove = function (predicate, context) {
-  let out = _.remove(this, predicate, context);
+  const out = _.remove(this, predicate, context);
   _.remove(this.raw, predicate, context);
   this._clearIndices();
   return out;
diff --git a/src/ui/public/indexed_array/inflector.js b/src/ui/public/indexed_array/inflector.js
index f879cbdf8965e..e2ef5eca31cda 100644
--- a/src/ui/public/indexed_array/inflector.js
+++ b/src/ui/public/indexed_array/inflector.js
@@ -8,7 +8,7 @@ function startsWith(str, test) {
 }
 
 function endsWith(str, test) {
-  let tooShort = str.length < test.length;
+  const tooShort = str.length < test.length;
   if (tooShort) return;
 
   return str.substr(str.length - test.length).toLowerCase() === test.toLowerCase();
diff --git a/src/ui/public/jquery/__tests__/find_test_subject.js b/src/ui/public/jquery/__tests__/find_test_subject.js
index 7a70ec05bd2a1..8302712e78f68 100644
--- a/src/ui/public/jquery/__tests__/find_test_subject.js
+++ b/src/ui/public/jquery/__tests__/find_test_subject.js
@@ -7,42 +7,42 @@ function $make(subject) {
 
 describe('jQuery.findTestSubject', function () {
   it('finds all of the element with a subject', function () {
-    let $container = $('<div>');
-    let $match = $make('subject').appendTo($container);
-    let $noMatch = $make('notSubject').appendTo($container);
+    const $container = $('<div>');
+    const $match = $make('subject').appendTo($container);
+    const $noMatch = $make('notSubject').appendTo($container);
 
-    let $found = $container.findTestSubject('subject');
+    const $found = $container.findTestSubject('subject');
     expect($found.is($match)).to.be(true);
     expect($found.is($noMatch)).to.be(false);
   });
 
   it('finds multiple elements with a subject', function () {
-    let $container = $('<div>');
-    let $match = $make('subject').appendTo($container);
-    let $otherMatch = $make('subject').appendTo($container);
+    const $container = $('<div>');
+    const $match = $make('subject').appendTo($container);
+    const $otherMatch = $make('subject').appendTo($container);
 
-    let $found = $container.findTestSubject('subject');
+    const $found = $container.findTestSubject('subject');
     expect($found.filter($match).size()).to.be(1);
     expect($found.filter($otherMatch).size()).to.be(1);
   });
 
   it('finds all of the elements with either subject', function () {
-    let $container = $('<div>');
-    let $match1 = $make('subject').appendTo($container);
-    let $match2 = $make('alsoSubject').appendTo($container);
-    let $noMatch = $make('notSubject').appendTo($container);
+    const $container = $('<div>');
+    const $match1 = $make('subject').appendTo($container);
+    const $match2 = $make('alsoSubject').appendTo($container);
+    const $noMatch = $make('notSubject').appendTo($container);
 
-    let $found = $container.findTestSubject('subject', 'alsoSubject');
+    const $found = $container.findTestSubject('subject', 'alsoSubject');
     expect($found.filter($match1).size()).to.be(1);
     expect($found.filter($match2).size()).to.be(1);
     expect($found.filter($noMatch).size()).to.be(0);
   });
 
   it('finds all of the elements with a decendant selector', function () {
-    let $container = $('<div>');
-    let $parent = $make('foo name').appendTo($container);
-    let $bar = $make('bar othername').appendTo($parent);
-    let $baz = $make('baz third name').appendTo($parent);
+    const $container = $('<div>');
+    const $parent = $make('foo name').appendTo($container);
+    const $bar = $make('bar othername').appendTo($parent);
+    const $baz = $make('baz third name').appendTo($parent);
 
     expect($container.findTestSubject('foo bar').is($bar)).to.be(true);
     expect($container.findTestSubject('foo bar').is($baz)).to.be(false);
@@ -52,9 +52,9 @@ describe('jQuery.findTestSubject', function () {
   });
 
   it('finds elements with compound subjects', function () {
-    let $container = $('<div>');
-    let $bar = $make('button bar').appendTo($container);
-    let $baz = $make('button baz').appendTo($container);
+    const $container = $('<div>');
+    const $bar = $make('button bar').appendTo($container);
+    const $baz = $make('button baz').appendTo($container);
 
     expect($container.findTestSubject('button&bar').is($bar)).to.be(true);
     expect($container.findTestSubject('button& bar').is($bar)).to.be(true);
diff --git a/src/ui/public/jquery/find_test_subject.js b/src/ui/public/jquery/find_test_subject.js
index 935bb67a14558..ecb85ea5944c9 100644
--- a/src/ui/public/jquery/find_test_subject.js
+++ b/src/ui/public/jquery/find_test_subject.js
@@ -45,7 +45,7 @@ module.exports = function bindToJquery($) {
 
   function findTestSubject(...subjectSelectors) {
     let $els = $();
-    let $context = this;
+    const $context = this;
 
     subjectSelectors.forEach(function (selector) {
       $els = $els.add($context.find(testSubjSelector(selector)));
diff --git a/src/ui/public/kbn_top_nav/__tests__/kbn_top_nav_controller.js b/src/ui/public/kbn_top_nav/__tests__/kbn_top_nav_controller.js
index bdb9759052e0d..e6fba1fbac2e4 100644
--- a/src/ui/public/kbn_top_nav/__tests__/kbn_top_nav_controller.js
+++ b/src/ui/public/kbn_top_nav/__tests__/kbn_top_nav_controller.js
@@ -303,7 +303,7 @@ describe('KbnTopNavController', function () {
         expect(controller.menuItems).to.have.length(4);
 
         // check that the items were added
-        let matches = controller.menuItems.reduce((acc, item) => {
+        const matches = controller.menuItems.reduce((acc, item) => {
           if (item.key === 'green' || item.key === 'red') {
             acc[item.key] = item;
           }
@@ -324,7 +324,7 @@ describe('KbnTopNavController', function () {
         expect(controller.menuItems).to.have.length(3);
 
         // check that the items were added
-        let match = controller.menuItems.filter((item) => {
+        const match = controller.menuItems.filter((item) => {
           return item.key === 'green';
         });
         expect(match[0]).to.have.property('run');
diff --git a/src/ui/public/listen/__tests__/listen.js b/src/ui/public/listen/__tests__/listen.js
index a4dcae53d176d..5c0384291f4e9 100644
--- a/src/ui/public/listen/__tests__/listen.js
+++ b/src/ui/public/listen/__tests__/listen.js
@@ -22,8 +22,8 @@ describe('listen component', function () {
   });
 
   it('binds to an event emitter', function () {
-    let emitter = new Events();
-    let $scope = $rootScope.$new();
+    const emitter = new Events();
+    const $scope = $rootScope.$new();
 
     function handler() {}
     $scope.$listen(emitter, 'hello', handler);
@@ -33,8 +33,8 @@ describe('listen component', function () {
   });
 
   it('binds to $scope, waiting for the destroy event', function () {
-    let emitter = new Events();
-    let $scope = $rootScope.$new();
+    const emitter = new Events();
+    const $scope = $rootScope.$new();
 
     sinon.stub($scope, '$on');
     sinon.stub($rootScope, '$on');
@@ -45,14 +45,14 @@ describe('listen component', function () {
     expect($rootScope.$on).to.have.property('callCount', 0);
     expect($scope.$on).to.have.property('callCount', 1);
 
-    let call = $scope.$on.firstCall;
+    const call = $scope.$on.firstCall;
     expect(call.args[0]).to.be('$destroy');
     expect(call.args[1]).to.be.a('function');
   });
 
   it('unbinds the event handler when $destroy is triggered', function () {
-    let emitter = new Events();
-    let $scope = $rootScope.$new();
+    const emitter = new Events();
+    const $scope = $rootScope.$new();
 
     sinon.stub($scope, '$on');
     sinon.stub(emitter, 'off');
@@ -62,7 +62,7 @@ describe('listen component', function () {
     $scope.$listen(emitter, 'hello', handler);
 
     // get the unbinder that was registered to $scope
-    let unbinder = $scope.$on.firstCall.args[1];
+    const unbinder = $scope.$on.firstCall.args[1];
 
     // call the unbinder
     expect(emitter.off).to.have.property('callCount', 0);
@@ -70,7 +70,7 @@ describe('listen component', function () {
     expect(emitter.off).to.have.property('callCount', 1);
 
     // check that the off args were as expected
-    let call = emitter.off.firstCall;
+    const call = emitter.off.firstCall;
     expect(call.args[0]).to.be('hello');
     expect(call.args[1]).to.be(handler);
   });
diff --git a/src/ui/public/notify/__tests__/lib/_format_es_msg.js b/src/ui/public/notify/__tests__/lib/_format_es_msg.js
index 5b89a909386bc..0fd73df79edc1 100644
--- a/src/ui/public/notify/__tests__/lib/_format_es_msg.js
+++ b/src/ui/public/notify/__tests__/lib/_format_es_msg.js
@@ -3,23 +3,23 @@ import expect from 'expect.js';
 describe('formatESMsg', function () {
 
   it('should return undefined if passed a basic error', function () {
-    let err = new Error('This is a normal error');
+    const err = new Error('This is a normal error');
 
-    let actual = formatESMsg(err);
+    const actual = formatESMsg(err);
 
     expect(actual).to.be(undefined);
   });
 
   it('should return undefined if passed a string', function () {
-    let err = 'This is a error string';
+    const err = 'This is a error string';
 
-    let actual = formatESMsg(err);
+    const actual = formatESMsg(err);
 
     expect(actual).to.be(undefined);
   });
 
   it('should return the root_cause if passed an extended elasticsearch', function () {
-    let err = new Error('This is an elasticsearch error');
+    const err = new Error('This is an elasticsearch error');
     err.resp = {
       error : {
         root_cause : [
@@ -30,13 +30,13 @@ describe('formatESMsg', function () {
       }
     };
 
-    let actual = formatESMsg(err);
+    const actual = formatESMsg(err);
 
     expect(actual).to.equal('I am the detailed message');
   });
 
   it('should combine the reason messages if more than one is returned.', function () {
-    let err = new Error('This is an elasticsearch error');
+    const err = new Error('This is an elasticsearch error');
     err.resp = {
       error : {
         root_cause : [
@@ -50,7 +50,7 @@ describe('formatESMsg', function () {
       }
     };
 
-    let actual = formatESMsg(err);
+    const actual = formatESMsg(err);
 
     expect(actual).to.equal('I am the detailed message 1\nI am the detailed message 2');
   });
diff --git a/src/ui/public/notify/__tests__/lib/_format_msg.js b/src/ui/public/notify/__tests__/lib/_format_msg.js
index 725fd6a518d73..a58f2fa4e2d72 100644
--- a/src/ui/public/notify/__tests__/lib/_format_msg.js
+++ b/src/ui/public/notify/__tests__/lib/_format_msg.js
@@ -3,26 +3,26 @@ import expect from 'expect.js';
 describe('formatMsg', function () {
 
   it('should prepend the second argument to result', function () {
-    let actual = formatMsg('error message', 'unit_test');
+    const actual = formatMsg('error message', 'unit_test');
 
     expect(actual).to.equal('unit_test: error message');
   });
 
   it('should handle a simple string', function () {
-    let actual = formatMsg('error message');
+    const actual = formatMsg('error message');
 
     expect(actual).to.equal('error message');
   });
 
   it('should handle a simple Error object', function () {
-    let err = new Error('error message');
-    let actual = formatMsg(err);
+    const err = new Error('error message');
+    const actual = formatMsg(err);
 
     expect(actual).to.equal('error message');
   });
 
   it('should handle a simple Angular $http error object', function () {
-    let err = {
+    const err = {
       data: {
         statusCode: 403,
         error: 'Forbidden',
@@ -32,13 +32,13 @@ describe('formatMsg', function () {
       config: {},
       statusText: 'Forbidden'
     };
-    let actual = formatMsg(err);
+    const actual = formatMsg(err);
 
     expect(actual).to.equal('Error 403 Forbidden: [security_exception] action [indices:data/read/mget] is unauthorized for user [user]');
   });
 
   it('should handle an extended elasticsearch error', function () {
-    let err = {
+    const err = {
       resp : {
         error : {
           root_cause : [
@@ -50,7 +50,7 @@ describe('formatMsg', function () {
       }
     };
 
-    let actual = formatMsg(err);
+    const actual = formatMsg(err);
 
     expect(actual).to.equal('I am the detailed message');
   });
diff --git a/src/ui/public/notify/__tests__/notifier.js b/src/ui/public/notify/__tests__/notifier.js
index 7fea469a37875..57902227cc6a2 100644
--- a/src/ui/public/notify/__tests__/notifier.js
+++ b/src/ui/public/notify/__tests__/notifier.js
@@ -67,7 +67,7 @@ describe('Notifier', function () {
     });
 
     it('sets timeRemaining and decrements', function () {
-      let notif = notify('error');
+      const notif = notify('error');
 
       expect(notif.timeRemaining).to.equal(300);
       $interval.flush(1000);
@@ -75,8 +75,8 @@ describe('Notifier', function () {
     });
 
     it('closes notification on lifetime expiry', function () {
-      let expectation = sinon.mock();
-      let notif = notifier.error(message, expectation);
+      const expectation = sinon.mock();
+      const notif = notifier.error(message, expectation);
 
       expectation.once();
       expectation.withExactArgs('ignore');
@@ -87,7 +87,7 @@ describe('Notifier', function () {
     });
 
     it('allows canceling of timer', function () {
-      let notif = notify('error');
+      const notif = notify('error');
 
       expect(notif.timerId).to.not.be(undefined);
       notif.cancelTimer();
@@ -96,7 +96,7 @@ describe('Notifier', function () {
     });
 
     it('resets timer on addition to stack', function () {
-      let notif = notify('error');
+      const notif = notify('error');
 
       $interval.flush(100000);
       expect(notif.timeRemaining).to.equal(200);
@@ -106,12 +106,12 @@ describe('Notifier', function () {
     });
 
     it('allows reporting', function () {
-      let includesReport = _.includes(notify('error').actions, 'report');
+      const includesReport = _.includes(notify('error').actions, 'report');
       expect(includesReport).to.true;
     });
 
     it('allows accepting', function () {
-      let includesAccept = _.includes(notify('error').actions, 'accept');
+      const includesAccept = _.includes(notify('error').actions, 'accept');
       expect(includesAccept).to.true;
     });
 
@@ -144,12 +144,12 @@ describe('Notifier', function () {
     });
 
     it('does not allow reporting', function () {
-      let includesReport = _.includes(notify('warning').actions, 'report');
+      const includesReport = _.includes(notify('warning').actions, 'report');
       expect(includesReport).to.false;
     });
 
     it('allows accepting', function () {
-      let includesAccept = _.includes(notify('warning').actions, 'accept');
+      const includesAccept = _.includes(notify('warning').actions, 'accept');
       expect(includesAccept).to.true;
     });
 
@@ -182,12 +182,12 @@ describe('Notifier', function () {
     });
 
     it('does not allow reporting', function () {
-      let includesReport = _.includes(notify('info').actions, 'report');
+      const includesReport = _.includes(notify('info').actions, 'report');
       expect(includesReport).to.false;
     });
 
     it('allows accepting', function () {
-      let includesAccept = _.includes(notify('info').actions, 'accept');
+      const includesAccept = _.includes(notify('info').actions, 'accept');
       expect(includesAccept).to.true;
     });
 
@@ -345,12 +345,12 @@ describe('Notifier', function () {
     });
 
     it('does not allow reporting', function () {
-      let includesReport = _.includes(notify('banner').actions, 'report');
+      const includesReport = _.includes(notify('banner').actions, 'report');
       expect(includesReport).to.false;
     });
 
     it('allows accepting', function () {
-      let includesAccept = _.includes(notify('banner').actions, 'accept');
+      const includesAccept = _.includes(notify('banner').actions, 'accept');
       expect(includesAccept).to.true;
     });
 
@@ -371,13 +371,13 @@ describe('Notifier', function () {
   function testVersionInfo(fnName) {
     context('when version is configured', function () {
       it('adds version to notification', function () {
-        let notification = notify(fnName);
+        const notification = notify(fnName);
         expect(notification.info.version).to.equal(version);
       });
     });
     context('when build number is configured', function () {
       it('adds buildNum to notification', function () {
-        let notification = notify(fnName);
+        const notification = notify(fnName);
         expect(notification.info.buildNum).to.equal(buildNum);
       });
     });
diff --git a/src/ui/public/notify/directives.js b/src/ui/public/notify/directives.js
index cb91b664d5403..bbef11f7e2bfe 100644
--- a/src/ui/public/notify/directives.js
+++ b/src/ui/public/notify/directives.js
@@ -5,7 +5,7 @@ import 'ui/notify/notify.less';
 import 'ui/filters/markdown';
 import 'ui/directives/truncated';
 
-let notify = uiModules.get('kibana/notify');
+const notify = uiModules.get('kibana/notify');
 
 notify.directive('kbnNotifications', function () {
   return {
diff --git a/src/ui/public/notify/errors.js b/src/ui/public/notify/errors.js
index 68a040466124f..85f4ed66c7d47 100644
--- a/src/ui/public/notify/errors.js
+++ b/src/ui/public/notify/errors.js
@@ -1,8 +1,8 @@
 import _ from 'lodash';
-let errors = {};
+const errors = {};
 
-let canStack = (function () {
-  let err = new Error();
+const canStack = (function () {
+  const err = new Error();
   return !!err.stack;
 }());
 
diff --git a/src/ui/public/notify/lib/_format_es_msg.js b/src/ui/public/notify/lib/_format_es_msg.js
index ac8c6b043a625..d812a04ec6eed 100644
--- a/src/ui/public/notify/lib/_format_es_msg.js
+++ b/src/ui/public/notify/lib/_format_es_msg.js
@@ -6,11 +6,11 @@ import _ from 'lodash';
  * @returns {string}
  */
 export default function formatESMsg(err) {
-  let rootCause = _.get(err, 'resp.error.root_cause');
+  const rootCause = _.get(err, 'resp.error.root_cause');
   if (!rootCause) {
     return; //undefined
   }
 
-  let result = _.pluck(rootCause, 'reason').join('\n');
+  const result = _.pluck(rootCause, 'reason').join('\n');
   return result;
 };
diff --git a/src/ui/public/notify/lib/_format_msg.js b/src/ui/public/notify/lib/_format_msg.js
index 448c4fa4b2c8c..c77b550b5d20a 100644
--- a/src/ui/public/notify/lib/_format_msg.js
+++ b/src/ui/public/notify/lib/_format_msg.js
@@ -1,6 +1,6 @@
 import _ from 'lodash';
 import formatESMsg from 'ui/notify/lib/_format_es_msg';
-let has = _.has;
+const has = _.has;
 
 /**
  * Formats the error message from an error object, extended elasticsearch
@@ -15,7 +15,7 @@ function formatMsg(err, from) {
     rtn += from + ': ';
   }
 
-  let esMsg = formatESMsg(err);
+  const esMsg = formatESMsg(err);
 
   if (typeof err === 'string') {
     rtn += err;
diff --git a/src/ui/public/notify/notifier.js b/src/ui/public/notify/notifier.js
index 2113ede5c288e..4352a0d333cf2 100644
--- a/src/ui/public/notify/notifier.js
+++ b/src/ui/public/notify/notifier.js
@@ -7,17 +7,17 @@ import fatalSplashScreen from 'ui/notify/partials/fatal_splash_screen.html';
 import 'ui/render_directive';
 /* eslint no-console: 0 */
 
-let notifs = [];
-let version = metadata.version;
-let buildNum = metadata.buildNum;
-let consoleGroups = ('group' in window.console) && ('groupCollapsed' in window.console) && ('groupEnd' in window.console);
+const notifs = [];
+const version = metadata.version;
+const buildNum = metadata.buildNum;
+const consoleGroups = ('group' in window.console) && ('groupCollapsed' in window.console) && ('groupEnd' in window.console);
 
-let log = _.bindKey(console, 'log');
+const log = _.bindKey(console, 'log');
 
 // used to identify the first call to fatal, set to false there
 let firstFatal = true;
 
-let fatalToastTemplate = (function lazyTemplate(tmpl) {
+const fatalToastTemplate = (function lazyTemplate(tmpl) {
   let compiled;
   return function (vars) {
     return (compiled || (compiled = _.template(tmpl)))(vars);
@@ -34,7 +34,7 @@ function now() {
 function closeNotif(notif, cb = _.noop, key) {
   return function () {
     // this === notif
-    let i = notifs.indexOf(notif);
+    const i = notifs.indexOf(notif);
     if (i !== -1) notifs.splice(i, 1);
 
     cancelTimer(notif);
@@ -151,7 +151,7 @@ Notifier.prototype.add = add;
 Notifier.prototype.set = set;
 
 function formatInfo() {
-  let info = [];
+  const info = [];
 
   if (!_.isUndefined(version)) {
     info.push(`Version: ${version}`);
@@ -176,7 +176,7 @@ function formatStack(err) {
  * Functionality to check that
  */
 function Notifier(opts) {
-  let self = this;
+  const self = this;
   opts = opts || {};
 
   // label type thing to say where notifications came from
@@ -254,7 +254,7 @@ Notifier.prototype.lifecycle = createGroupLogger('lifecycle', {
  * @return {function} - the wrapped function
  */
 Notifier.prototype.timed = function (name, fn) {
-  let self = this;
+  const self = this;
 
   if (typeof name === 'function') {
     fn = name;
@@ -262,8 +262,8 @@ Notifier.prototype.timed = function (name, fn) {
   }
 
   return function WrappedNotifierFunction() {
-    let cntx = this;
-    let args = arguments;
+    const cntx = this;
+    const args = arguments;
 
     return self.event(name, function () {
       return fn.apply(cntx, args);
@@ -299,7 +299,7 @@ Notifier.prototype._showFatal = function (err) {
     });
   }
 
-  let html = fatalToastTemplate({
+  const html = fatalToastTemplate({
     info: formatInfo(),
     msg: formatMsg(err, this.from),
     stack: formatStack(err)
@@ -539,7 +539,7 @@ if (log === _.noop) {
   Notifier.prototype.log = _.noop;
 } else {
   Notifier.prototype.log = function () {
-    let args = [].slice.apply(arguments);
+    const args = [].slice.apply(arguments);
     if (this.from) args.unshift(this.from + ':');
     log.apply(null, args);
   };
@@ -548,15 +548,15 @@ if (log === _.noop) {
 // general functionality used by .event() and .lifecycle()
 function createGroupLogger(type, opts) {
   // Track the groups managed by this logger
-  let groups = window[type + 'Groups'] = {};
+  const groups = window[type + 'Groups'] = {};
 
   return function logger(name, success) {
     let status; // status of the timer
     let exec; // function to execute and wrap
     let ret; // return value
 
-    let complete = function (val) { logger(name, true); return val; };
-    let failure = function (err) { logger(name, false); throw err; };
+    const complete = function (val) { logger(name, true); return val; };
+    const failure = function (err) { logger(name, false); throw err; };
 
     if (typeof success === 'function' || success === void 0) {
       // start
@@ -572,7 +572,7 @@ function createGroupLogger(type, opts) {
     }
     else {
       groups[name] = now() - (groups[name] || 0);
-      let time = ' in ' + groups[name].toFixed(2) + 'ms';
+      const time = ' in ' + groups[name].toFixed(2) + 'ms';
 
       // end
       if (success) {
diff --git a/src/ui/public/notify/notify.js b/src/ui/public/notify/notify.js
index bcfa025cfcdea..76af7d3be906b 100644
--- a/src/ui/public/notify/notify.js
+++ b/src/ui/public/notify/notify.js
@@ -6,8 +6,8 @@ import Notifier from 'ui/notify/notifier';
 import 'ui/notify/directives';
 import chrome from 'ui/chrome';
 import { kbnIndex } from 'ui/metadata';
-let module = modules.get('kibana/notify');
-let rootNotifier = new Notifier();
+const module = modules.get('kibana/notify');
+const rootNotifier = new Notifier();
 
 module.factory('createNotifier', function () {
   return function (opts) {
diff --git a/src/ui/public/number_list/number_list.js b/src/ui/public/number_list/number_list.js
index 9c18da1f3058f..03206d8d4cd01 100644
--- a/src/ui/public/number_list/number_list.js
+++ b/src/ui/public/number_list/number_list.js
@@ -13,7 +13,7 @@ uiModules
     controllerAs: 'numberListCntr',
     require: 'ngModel',
     controller: function ($scope, $attrs, $parse) {
-      let self = this;
+      const self = this;
 
       // Called from the pre-link function once we have the controllers
       self.init = function (modelCntr) {
@@ -25,7 +25,7 @@ uiModules
 
         self.getUnitName = _.partial($parse($attrs.unit), $scope);
 
-        let defaultRange = self.range = parseRange('[0,Infinity)');
+        const defaultRange = self.range = parseRange('[0,Infinity)');
 
         $scope.$watch(function () {
           return $attrs.range;
@@ -48,7 +48,7 @@ uiModules
          * @return {undefined}
          */
         self.remove = function (index) {
-          let list = self.getList();
+          const list = self.getList();
           if (!list) return;
 
           list.splice(index, 1);
@@ -59,7 +59,7 @@ uiModules
          * @return {undefined}
          */
         self.add = function () {
-          let list = self.getList();
+          const list = self.getList();
           if (!list) return;
 
           list.push(_.last(list) + 1);
diff --git a/src/ui/public/number_list/number_list_input.js b/src/ui/public/number_list/number_list_input.js
index 7fbf1b935e02f..21fe02ddf259a 100644
--- a/src/ui/public/number_list/number_list_input.js
+++ b/src/ui/public/number_list/number_list_input.js
@@ -3,11 +3,11 @@ import _ from 'lodash';
 import keyMap from 'ui/utils/key_map';
 import uiModules from 'ui/modules';
 
-let INVALID = {}; // invalid flag
-let FLOATABLE = /^[\d\.e\-\+]+$/i;
+const INVALID = {}; // invalid flag
+const FLOATABLE = /^[\d\.e\-\+]+$/i;
 
-let VALIDATION_ERROR = 'numberListRangeAndOrder';
-let DIRECTIVE_ATTR = 'kbn-number-list-input';
+const VALIDATION_ERROR = 'numberListRangeAndOrder';
+const DIRECTIVE_ATTR = 'kbn-number-list-input';
 
 uiModules
 .get('kibana')
@@ -16,13 +16,13 @@ uiModules
     restrict: 'A',
     require: ['ngModel', '^kbnNumberList'],
     link: function ($scope, $el, attrs, controllers) {
-      let ngModelCntr = controllers[0];
-      let numberListCntr = controllers[1];
+      const ngModelCntr = controllers[0];
+      const numberListCntr = controllers[1];
 
-      let $setModel = $parse(attrs.ngModel).assign;
-      let $repeater = $el.closest('[ng-repeat]');
+      const $setModel = $parse(attrs.ngModel).assign;
+      const $repeater = $el.closest('[ng-repeat]');
 
-      let handlers = {
+      const handlers = {
         up: change(add, 1),
         'shift-up': change(addTenth, 1),
 
@@ -54,14 +54,14 @@ uiModules
 
       function go(dir) {
         return function () {
-          let $to = $get(dir);
+          const $to = $get(dir);
           if ($to.size()) $to.focus();
           else return false;
         };
       }
 
       function idKey(event) {
-        let id = [];
+        const id = [];
         if (event.ctrlKey) id.push('ctrl');
         if (event.shiftKey) id.push('shift');
         if (event.metaKey) id.push('meta');
@@ -93,11 +93,11 @@ uiModules
 
       function change(using, mod) {
         return function () {
-          let str = String(ngModelCntr.$viewValue);
-          let val = parse(str);
+          const str = String(ngModelCntr.$viewValue);
+          const val = parse(str);
           if (val === INVALID) return;
 
-          let next = using(mod, val, str);
+          const next = using(mod, val, str);
           if (next === INVALID) return;
 
           $el.val(next);
@@ -106,7 +106,7 @@ uiModules
       }
 
       function onKeydown(event) {
-        let handler = handlers[idKey(event)];
+        const handler = handlers[idKey(event)];
         if (!handler) return;
 
         if (handler(event) !== false) {
@@ -133,13 +133,13 @@ uiModules
           if (isNaN(num)) return INVALID;
         }
 
-        let range = numberListCntr.range;
+        const range = numberListCntr.range;
         if (!range.within(num)) return INVALID;
 
         if ($scope.$index > 0) {
-          let i = $scope.$index - 1;
-          let list = numberListCntr.getList();
-          let prev = list[i];
+          const i = $scope.$index - 1;
+          const list = numberListCntr.getList();
+          const prev = list[i];
           if (num <= prev) return INVALID;
         }
 
@@ -155,14 +155,14 @@ uiModules
           }
         }
       ], function () {
-        let valid = parse(ngModelCntr.$viewValue) !== INVALID;
+        const valid = parse(ngModelCntr.$viewValue) !== INVALID;
         ngModelCntr.$setValidity(VALIDATION_ERROR, valid);
       });
 
       function validate(then) {
         return function (input) {
           let value = parse(input);
-          let valid = value !== INVALID;
+          const valid = value !== INVALID;
           value = valid ? value : input;
           ngModelCntr.$setValidity(VALIDATION_ERROR, valid);
           then && then(input, value);
diff --git a/src/ui/public/paginated_table/__tests__/index.js b/src/ui/public/paginated_table/__tests__/index.js
index 945118d794a70..08057156b65a4 100644
--- a/src/ui/public/paginated_table/__tests__/index.js
+++ b/src/ui/public/paginated_table/__tests__/index.js
@@ -13,9 +13,9 @@ describe('paginated table', function () {
   let $scope;
   let $elScope;
   let $orderBy;
-  let defaultPerPage = 10;
+  const defaultPerPage = 10;
 
-  let makeData = function (colCount, rowCount) {
+  const makeData = function (colCount, rowCount) {
     let columns = [];
     let rows = [];
 
@@ -29,7 +29,7 @@ describe('paginated table', function () {
 
     if (_.isNumber(rowCount)) {
       _.times(rowCount, function (col) {
-        let rowItems = [];
+        const rowItems = [];
 
         _.times(columns.length, function (row) {
           rowItems.push('item' + col + row);
@@ -47,7 +47,7 @@ describe('paginated table', function () {
     };
   };
 
-  let renderTable = function (cols, rows, perPage, sort) {
+  const renderTable = function (cols, rows, perPage, sort) {
     $scope.cols = cols || [];
     $scope.rows = rows || [];
     $scope.perPage = perPage || defaultPerPage;
@@ -68,23 +68,23 @@ describe('paginated table', function () {
 
   describe('rendering', function () {
     it('should not display without rows', function () {
-      let cols = [{
+      const cols = [{
         title: 'test1'
       }];
-      let rows = [];
+      const rows = [];
 
       renderTable(cols, rows);
       expect($el.children().size()).to.be(0);
     });
 
     it('should render columns and rows', function () {
-      let data = makeData(2, 2);
-      let cols = data.columns;
-      let rows = data.rows;
+      const data = makeData(2, 2);
+      const cols = data.columns;
+      const rows = data.rows;
 
       renderTable(cols, rows);
       expect($el.children().size()).to.be(1);
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       // should pad rows
       expect(tableRows.size()).to.be(defaultPerPage);
       // should contain the row data
@@ -96,13 +96,13 @@ describe('paginated table', function () {
 
     it('should paginate rows', function () {
       // note: paginate truncates pages, so don't make too many
-      let rowCount = _.random(16, 24);
-      let perPageCount = _.random(5, 8);
-      let data = makeData(3, rowCount);
-      let pageCount = Math.ceil(rowCount / perPageCount);
+      const rowCount = _.random(16, 24);
+      const perPageCount = _.random(5, 8);
+      const data = makeData(3, rowCount);
+      const pageCount = Math.ceil(rowCount / perPageCount);
 
       renderTable(data.columns, data.rows, perPageCount);
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.size()).to.be(perPageCount);
       // add 2 for the first and last page links
       expect($el.find('paginate-controls a').size()).to.be(pageCount + 2);
@@ -132,7 +132,7 @@ describe('paginated table', function () {
     // });
 
     it('should not sort by default', function () {
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(0).text()).to.be(data.rows[0][0]);
       expect(tableRows.eq(lastRowIndex).find('td').eq(0).text()).to.be(data.rows[lastRowIndex][0]);
     });
@@ -142,7 +142,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(999);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(0).text()).to.be('bbbb');
       expect(tableRows.eq(0).find('td').eq(1).text()).to.be('aaaa');
       expect(tableRows.eq(0).find('td').eq(2).text()).to.be('zzzz');
@@ -155,7 +155,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(0);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(0).text()).to.be('bbbb');
       expect(tableRows.eq(0).find('td').eq(1).text()).to.be('aaaa');
       expect(tableRows.eq(0).find('td').eq(2).text()).to.be('zzzz');
@@ -165,7 +165,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(1);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(2).find('td').eq(1).text()).to.be('cccc');
       expect(tableRows.eq(1).find('td').eq(1).text()).to.be('bbbb');
       expect(tableRows.eq(0).find('td').eq(1).text()).to.be('aaaa');
@@ -175,7 +175,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(1, 'desc');
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(1).text()).to.be('zzzz');
       expect(tableRows.eq(1).find('td').eq(1).text()).to.be('cccc');
       expect(tableRows.eq(2).find('td').eq(1).text()).to.be('bbbb');
@@ -186,7 +186,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(0);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(0).text()).to.be('aaaa');
       expect(tableRows.eq(lastRowIndex).find('td').eq(0).text()).to.be('zzzz');
     });
@@ -197,7 +197,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(0);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(0).text()).to.be('zzzz');
       expect(tableRows.eq(lastRowIndex).find('td').eq(0).text()).to.be('aaaa');
     });
@@ -209,7 +209,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(0);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(0).text()).to.be(data.rows[0][0]);
       expect(tableRows.eq(lastRowIndex).find('td').eq(0).text()).to.be('aaaa');
     });
@@ -223,7 +223,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(1);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(1).text()).to.be('aaaa');
       expect(tableRows.eq(lastRowIndex).find('td').eq(1).text()).to.be('zzzz');
     });
@@ -233,15 +233,15 @@ describe('paginated table', function () {
   describe('sorting duplicate columns', function () {
     let data;
     let paginatedTable;
-    let colText = 'test row';
+    const colText = 'test row';
 
     beforeEach(function () {
-      let cols = [
+      const cols = [
         { title: colText },
         { title: colText },
         { title: colText }
       ];
-      let rows = [
+      const rows = [
         ['bbbb', 'aaaa', 'zzzz'],
         ['cccc', 'cccc', 'aaaa'],
         ['zzzz', 'bbbb', 'bbbb'],
@@ -254,7 +254,7 @@ describe('paginated table', function () {
     });
 
     it('should have duplicate column titles', function () {
-      let columns = $el.find('thead th span');
+      const columns = $el.find('thead th span');
       columns.each(function () {
         expect($(this).text()).to.be(colText);
       });
@@ -265,7 +265,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(2);
       $scope.$digest();
 
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('td').eq(0).text()).to.be('cccc');
       expect(tableRows.eq(0).find('td').eq(1).text()).to.be('cccc');
       expect(tableRows.eq(0).find('td').eq(2).text()).to.be('aaaa');
@@ -302,7 +302,7 @@ describe('paginated table', function () {
       paginatedTable.sortColumn(1);
       $scope.$digest();
 
-      let sorters = $el.find('thead th i');
+      const sorters = $el.find('thead th i');
       expect(sorters.eq(0).hasClass('fa-sort')).to.be(true);
       expect(sorters.eq(1).hasClass('fa-sort')).to.be(false);
       expect(sorters.eq(2).hasClass('fa-sort')).to.be(true);
@@ -333,7 +333,7 @@ describe('paginated table', function () {
     });
 
     it('should append object markup', function () {
-      let tableRows = $el.find('tbody tr');
+      const tableRows = $el.find('tbody tr');
       expect(tableRows.eq(0).find('h1').size()).to.be(0);
       expect(tableRows.eq(1).find('h1').size()).to.be(1);
       expect(tableRows.eq(2).find('h1').size()).to.be(0);
diff --git a/src/ui/public/parse_query/lib/from_user.js b/src/ui/public/parse_query/lib/from_user.js
index 6aac1f93c0feb..85b1ac423364f 100644
--- a/src/ui/public/parse_query/lib/from_user.js
+++ b/src/ui/public/parse_query/lib/from_user.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import DecorateQueryProvider from 'ui/courier/data_source/_decorate_query';
 export default function GetQueryFromUser(es, Private) {
-  let decorateQuery = Private(DecorateQueryProvider);
+  const decorateQuery = Private(DecorateQueryProvider);
 
   /**
    * Take text from the user and make it into a query object
@@ -13,7 +13,7 @@ export default function GetQueryFromUser(es, Private) {
       return decorateQuery({query_string: {query: text}});
     }
 
-    let matchAll = getQueryStringQuery('*');
+    const matchAll = getQueryStringQuery('*');
 
     // If we get an empty object, treat it as a *
     if (_.isObject(text)) {
diff --git a/src/ui/public/parse_query/parse_query.js b/src/ui/public/parse_query/parse_query.js
index 148a2f962f796..8d1ea46ddf4a8 100644
--- a/src/ui/public/parse_query/parse_query.js
+++ b/src/ui/public/parse_query/parse_query.js
@@ -4,7 +4,7 @@ import uiModules from 'ui/modules';
 uiModules
   .get('kibana')
   .directive('parseQuery', function (Private) {
-    let fromUser = Private(ParseQueryLibFromUserProvider);
+    const fromUser = Private(ParseQueryLibFromUserProvider);
 
     return {
       restrict: 'A',
@@ -13,7 +13,7 @@ uiModules
         'ngModel': '='
       },
       link: function ($scope, elem, attr, ngModel) {
-        let init = function () {
+        const init = function () {
           $scope.ngModel = fromUser($scope.ngModel);
         };
 
diff --git a/src/ui/public/pattern_checker/pattern_checker.js b/src/ui/public/pattern_checker/pattern_checker.js
index 134bfce760f61..bec93a9471ce3 100644
--- a/src/ui/public/pattern_checker/pattern_checker.js
+++ b/src/ui/public/pattern_checker/pattern_checker.js
@@ -17,7 +17,7 @@ module.directive('patternChecker', function () {
     controller: function (Notifier, $scope, $timeout, $http) {
       let validationTimeout;
 
-      let notify = new Notifier({
+      const notify = new Notifier({
         location: 'Add Data'
       });
 
diff --git a/src/ui/public/persisted_log/__tests__/persisted_log.js b/src/ui/public/persisted_log/__tests__/persisted_log.js
index 11115f087e6f8..eff9efa14870c 100644
--- a/src/ui/public/persisted_log/__tests__/persisted_log.js
+++ b/src/ui/public/persisted_log/__tests__/persisted_log.js
@@ -8,9 +8,9 @@ let storage;
 let config;
 let PersistedLog;
 
-let historyName = 'testHistory';
-let historyLimit = 10;
-let payload = [
+const historyName = 'testHistory';
+const historyLimit = 10;
+const payload = [
   { first: 'clark', last: 'kent' },
   { first: 'peter', last: 'parker' },
   { first: 'bruce', last: 'wayne' }
@@ -41,7 +41,7 @@ describe('PersistedLog', function () {
 
   describe('expected API', function () {
     it('has expected methods', function () {
-      let log = new PersistedLog(historyName);
+      const log = new PersistedLog(historyName);
 
       expect(log.add).to.be.a('function');
       expect(log.get).to.be.a('function');
@@ -50,17 +50,17 @@ describe('PersistedLog', function () {
 
   describe('internal functionality', function () {
     it('reads from storage', function () {
-      let log = new PersistedLog(historyName);
+      const log = new PersistedLog(historyName);
 
       expect(storage.get.calledOnce).to.be(true);
       expect(storage.get.calledWith(historyName)).to.be(true);
     });
 
     it('writes to storage', function () {
-      let log = new PersistedLog(historyName);
-      let newItem = { first: 'diana', last: 'prince' };
+      const log = new PersistedLog(historyName);
+      const newItem = { first: 'diana', last: 'prince' };
 
-      let data = log.add(newItem);
+      const data = log.add(newItem);
 
       expect(storage.set.calledOnce).to.be(true);
       expect(data).to.eql([newItem]);
@@ -70,19 +70,19 @@ describe('PersistedLog', function () {
   describe('persisting data', function () {
     it('fetches records from storage', function () {
       storage.get.returns(payload);
-      let log = new PersistedLog(historyName);
+      const log = new PersistedLog(historyName);
 
-      let items = log.get();
+      const items = log.get();
       expect(items.length).to.equal(3);
       expect(items).to.eql(payload);
     });
 
     it('prepends new records', function () {
       storage.get.returns(payload.slice(0));
-      let log = new PersistedLog(historyName);
-      let newItem = { first: 'selina', last: 'kyle' };
+      const log = new PersistedLog(historyName);
+      const newItem = { first: 'selina', last: 'kyle' };
 
-      let items = log.add(newItem);
+      const items = log.add(newItem);
       expect(items.length).to.equal(payload.length + 1);
       expect(items[0]).to.eql(newItem);
     });
@@ -90,40 +90,40 @@ describe('PersistedLog', function () {
 
   describe('stack options', function () {
     it('should observe the maxLength option', function () {
-      let bulkData = [];
+      const bulkData = [];
 
       for (let i = 0; i < historyLimit; i++) {
         bulkData.push(['record ' + i]);
       }
       storage.get.returns(bulkData);
 
-      let log = new PersistedLog(historyName, { maxLength: historyLimit });
+      const log = new PersistedLog(historyName, { maxLength: historyLimit });
       log.add(['new array 1']);
-      let items = log.add(['new array 2']);
+      const items = log.add(['new array 2']);
 
       expect(items.length).to.equal(historyLimit);
     });
 
     it('should observe the filterDuplicates option', function () {
       storage.get.returns(payload.slice(0));
-      let log = new PersistedLog(historyName, { filterDuplicates: true });
-      let newItem = payload[1];
+      const log = new PersistedLog(historyName, { filterDuplicates: true });
+      const newItem = payload[1];
 
-      let items = log.add(newItem);
+      const items = log.add(newItem);
       expect(items.length).to.equal(payload.length);
     });
 
     it ('should truncate the list upon initialization if too long', () => {
       storage.get.returns(payload.slice(0));
-      let log = new PersistedLog(historyName, {maxLength: 1});
-      let items = log.get();
+      const log = new PersistedLog(historyName, {maxLength: 1});
+      const items = log.get();
       expect(items.length).to.equal(1);
     });
 
     it('should allow a maxLength of 0', () => {
       storage.get.returns(payload.slice(0));
-      let log = new PersistedLog(historyName, {maxLength: 0});
-      let items = log.get();
+      const log = new PersistedLog(historyName, {maxLength: 0});
+      const items = log.get();
       expect(items.length).to.equal(0);
     });
   });
diff --git a/src/ui/public/persisted_state/__tests__/persisted_state.js b/src/ui/public/persisted_state/__tests__/persisted_state.js
index af6a2deb3c9cf..e988bbf473aa7 100644
--- a/src/ui/public/persisted_state/__tests__/persisted_state.js
+++ b/src/ui/public/persisted_state/__tests__/persisted_state.js
@@ -36,7 +36,7 @@ describe('Persisted State', function () {
     });
 
     it('should create a state instance with data', function () {
-      let val = { red: 'blue' };
+      const val = { red: 'blue' };
       persistedState = new PersistedState(val);
 
       expect(persistedState.get()).to.eql(val);
@@ -45,7 +45,7 @@ describe('Persisted State', function () {
     });
 
     it('should create a copy of the state passed in', function () {
-      let val = { red: 'blue' };
+      const val = { red: 'blue' };
       persistedState = new PersistedState(val);
 
       expect(persistedState.get()).to.eql(val);
@@ -53,10 +53,10 @@ describe('Persisted State', function () {
     });
 
     it('should not throw if creating valid child object', function () {
-      let run = function () {
-        let val = { red: 'blue' };
-        let path = ['test.path'];
-        let parent = new PersistedState();
+      const run = function () {
+        const val = { red: 'blue' };
+        const path = ['test.path'];
+        const parent = new PersistedState();
         new PersistedState(val, path, parent);
       };
 
@@ -64,8 +64,8 @@ describe('Persisted State', function () {
     });
 
     it('should throw if given an invalid value', function () {
-      let run = function () {
-        let val = 'bananas';
+      const run = function () {
+        const val = 'bananas';
         new PersistedState(val);
       };
 
@@ -75,10 +75,10 @@ describe('Persisted State', function () {
     });
 
     it('should not throw if given primitive to child', function () {
-      let run = function () {
-        let val = 'bananas';
-        let path = ['test.path'];
-        let parent = new PersistedState();
+      const run = function () {
+        const val = 'bananas';
+        const path = ['test.path'];
+        const parent = new PersistedState();
         new PersistedState(val, path, parent);
       };
 
@@ -86,10 +86,10 @@ describe('Persisted State', function () {
     });
 
     it('should throw if given an invalid parent object', function () {
-      let run = function () {
-        let val = { red: 'blue' };
-        let path = ['test.path'];
-        let parent = {};
+      const run = function () {
+        const val = { red: 'blue' };
+        const path = ['test.path'];
+        const parent = {};
         new PersistedState(val, path, parent);
       };
 
@@ -99,10 +99,10 @@ describe('Persisted State', function () {
     });
 
     it('should throw if given a parent without a path', function () {
-      let run = function () {
-        let val = { red: 'blue' };
+      const run = function () {
+        const val = { red: 'blue' };
         let path;
-        let parent = new PersistedState();
+        const parent = new PersistedState();
 
         new PersistedState(val, path, parent);
       };
@@ -117,8 +117,8 @@ describe('Persisted State', function () {
     let childState;
 
     it('should not append the child state to the parent, without parent value', function () {
-      let childIndex = 'i can haz child';
-      let persistedState = new PersistedState();
+      const childIndex = 'i can haz child';
+      const persistedState = new PersistedState();
       childState = persistedState.createChild(childIndex);
 
       // parent state should not contain the child state
@@ -127,9 +127,9 @@ describe('Persisted State', function () {
     });
 
     it('should not append the child state to the parent, with parent value', function () {
-      let childIndex = 'i can haz child';
-      let persistedStateValue = { original: true };
-      let persistedState = new PersistedState(persistedStateValue);
+      const childIndex = 'i can haz child';
+      const persistedStateValue = { original: true };
+      const persistedState = new PersistedState(persistedStateValue);
       childState = persistedState.createChild(childIndex);
 
       // child state should be empty, we didn't give it any default data
@@ -141,14 +141,14 @@ describe('Persisted State', function () {
     });
 
     it('should append the child state to the parent, with parent and child values', function () {
-      let childIndex = 'i can haz child';
-      let childStateValue = { tacos: 'yes please' };
-      let persistedStateValue = { original: true };
-      let persistedState = new PersistedState(persistedStateValue);
+      const childIndex = 'i can haz child';
+      const childStateValue = { tacos: 'yes please' };
+      const persistedStateValue = { original: true };
+      const persistedState = new PersistedState(persistedStateValue);
       childState = persistedState.createChild(childIndex, childStateValue);
 
       // parent state should contain the child and its original state value
-      let parentState = persistedState.get();
+      const parentState = persistedState.get();
       expect(parentState).to.have.property('original', true);
       expect(parentState).to.have.property(childIndex);
       expect(parentState[childIndex]).to.eql(childStateValue);
@@ -157,15 +157,15 @@ describe('Persisted State', function () {
 
   describe('deep child state creation', function () {
     it('should delegate get/set calls to parent state', function () {
-      let children = [{
+      const children = [{
         path: 'first*child',
         value: { first: true, second: false }
       }, {
         path: 'second child',
         value: { first: false, second: true }
       }];
-      let persistedStateValue = { original: true };
-      let persistedState = new PersistedState(persistedStateValue);
+      const persistedStateValue = { original: true };
+      const persistedState = new PersistedState(persistedStateValue);
 
       // first child is a child of the parent persistedState
       children[0].instance = persistedState.createChild(children[0].path, children[0].value);
@@ -176,7 +176,7 @@ describe('Persisted State', function () {
       expect(children[1].instance.get()).to.eql(children[1].value);
 
       // parent should contain original props and first child path, but not the second child path
-      let parentState = persistedState.get();
+      const parentState = persistedState.get();
       _.keys(persistedStateValue).forEach(function (key) {
         expect(parentState).to.have.property(key);
       });
@@ -184,28 +184,28 @@ describe('Persisted State', function () {
       expect(parentState).to.not.have.property(children[1].path);
 
       // second child path should be inside the first child
-      let firstChildState = children[0].instance.get();
+      const firstChildState = children[0].instance.get();
       expect(firstChildState).to.have.property(children[1].path);
       expect(firstChildState[children[1].path]).to.eql(children[1].value);
 
       // check that the second child is still accessible from the parent instance
-      let firstChild = persistedState.get(children[0].path);
+      const firstChild = persistedState.get(children[0].path);
       expect(firstChild).to.have.property(children[1].path);
     });
   });
 
   describe('child state removal', function () {
     it('should clear path from parent state', function () {
-      let persistedState = new PersistedState();
-      let childState = persistedState.createChild('child', { userId: 1234 });
+      const persistedState = new PersistedState();
+      const childState = persistedState.createChild('child', { userId: 1234 });
       expect(persistedState.get()).to.eql({ child: { userId: 1234 }});
       persistedState.removeChild('child');
       expect(persistedState.get()).to.eql({});
     });
 
     it('should reset original parent value at path', function () {
-      let persistedState = new PersistedState({ user: 1234 });
-      let childState = persistedState.createChild('user', { id: 5678 });
+      const persistedState = new PersistedState({ user: 1234 });
+      const childState = persistedState.createChild('user', { id: 5678 });
       expect(persistedState.get()).to.eql({ user: { id: 5678 }});
 
       persistedState.removeChild('user');
@@ -213,8 +213,8 @@ describe('Persisted State', function () {
     });
 
     it('should clear changedState', function () {
-      let persistedState = new PersistedState({ user: 1234 });
-      let childState = persistedState.createChild('user');
+      const persistedState = new PersistedState({ user: 1234 });
+      const childState = persistedState.createChild('user');
       childState.set('name', 'user name');
       expect(persistedState.getChanges()).to.eql({ user: { name: 'user name' }});
 
@@ -225,16 +225,16 @@ describe('Persisted State', function () {
 
   describe('deep child state removal', function () {
     it('should clear path from parent state', function () {
-      let persistedState = new PersistedState();
-      let childState = persistedState.createChild('child.state', { userId: 1234 });
+      const persistedState = new PersistedState();
+      const childState = persistedState.createChild('child.state', { userId: 1234 });
       expect(persistedState.get()).to.eql({ child: { state: { userId: 1234 }}});
       persistedState.removeChild('child.state');
       expect(persistedState.get()).to.eql({});
     });
 
     it('should reset original parent value at path', function () {
-      let persistedState = new PersistedState({ user: { id: 1234 }});
-      let childState = persistedState.createChild('user.id', 5678);
+      const persistedState = new PersistedState({ user: { id: 1234 }});
+      const childState = persistedState.createChild('user.id', 5678);
       expect(persistedState.get()).to.eql({ user: { id: 5678 }});
 
       persistedState.removeChild('user.id');
@@ -242,8 +242,8 @@ describe('Persisted State', function () {
     });
 
     it('should reset original parent other values at path', function () {
-      let persistedState = new PersistedState({ user: { name: 'user' }});
-      let childState = persistedState.createChild('user.id', 5678);
+      const persistedState = new PersistedState({ user: { name: 'user' }});
+      const childState = persistedState.createChild('user.id', 5678);
       expect(persistedState.get()).to.eql({ user: { name: 'user', id: 5678 }});
 
       persistedState.removeChild('user.id');
@@ -251,8 +251,8 @@ describe('Persisted State', function () {
     });
 
     it('should clear the changed state', function () {
-      let persistedState = new PersistedState({ user: { id: 1234 }});
-      let childState = persistedState.createChild('user.name');
+      const persistedState = new PersistedState({ user: { id: 1234 }});
+      const childState = persistedState.createChild('user.name');
       childState.set('user name');
       expect(persistedState.getChanges()).to.eql({ user: { name: 'user name' }});
 
@@ -264,8 +264,8 @@ describe('Persisted State', function () {
 
   describe('child state conditions', function () {
     it('should be merged with the parent state', function () {
-      let parent = new PersistedState({ name: 'test' });
-      let child = parent.createChild('child', 'value');
+      const parent = new PersistedState({ name: 'test' });
+      const child = parent.createChild('child', 'value');
       expect(parent.get()).to.eql({
         name: 'test',
         child: 'value'
@@ -285,8 +285,8 @@ describe('Persisted State', function () {
     });
 
     it('should give child state precedence', function () {
-      let parent = new PersistedState({ user: { id: 1234, name: 'test' }});
-      let child = parent.createChild('user', { name: 'child test' });
+      const parent = new PersistedState({ user: { id: 1234, name: 'test' }});
+      const child = parent.createChild('user', { name: 'child test' });
       expect(parent.get()).to.eql({
         user: {
           id: 1234,
@@ -299,8 +299,8 @@ describe('Persisted State', function () {
     });
 
     it('should be cleaned up with removeChild', function () {
-      let parent = new PersistedState({ name: 'test' });
-      let child = parent.createChild('child', 'value');
+      const parent = new PersistedState({ name: 'test' });
+      const child = parent.createChild('child', 'value');
       expect(parent.get()).to.eql({
         name: 'test',
         child: 'value'
@@ -315,16 +315,16 @@ describe('Persisted State', function () {
 
   describe('colliding child paths and parent state values', function () {
     it('should not change the child path value by default', function () {
-      let childIndex = 'childTest';
-      let persistedStateValue = {};
+      const childIndex = 'childTest';
+      const persistedStateValue = {};
       persistedStateValue[childIndex] = { overlapping_index: true };
 
-      let persistedState = new PersistedState(persistedStateValue);
+      const persistedState = new PersistedState(persistedStateValue);
       let state = persistedState.get();
       expect(state).to.have.property(childIndex);
       expect(state[childIndex]).to.eql(persistedStateValue[childIndex]);
 
-      let childState = persistedState.createChild(childIndex);
+      const childState = persistedState.createChild(childIndex);
       expect(childState.get()).to.eql(persistedStateValue[childIndex]);
 
       // make sure the parent state is still the same
@@ -334,21 +334,21 @@ describe('Persisted State', function () {
     });
 
     it('should merge default child state', function () {
-      let childIndex = 'childTest';
-      let childStateValue = { child_index: false };
-      let persistedStateValue = {};
+      const childIndex = 'childTest';
+      const childStateValue = { child_index: false };
+      const persistedStateValue = {};
       persistedStateValue[childIndex] = { parent_index: true };
 
-      let persistedState = new PersistedState(persistedStateValue);
+      const persistedState = new PersistedState(persistedStateValue);
       let state = persistedState.get();
       expect(state).to.have.property(childIndex);
       expect(state[childIndex]).to.eql(persistedStateValue[childIndex]);
 
       // pass in child state value
-      let childState = persistedState.createChild(childIndex, childStateValue);
+      const childState = persistedState.createChild(childIndex, childStateValue);
 
       // parent's default state is merged with child state
-      let compare = _.merge({}, childStateValue, persistedStateValue[childIndex]);
+      const compare = _.merge({}, childStateValue, persistedStateValue[childIndex]);
       expect(childState.get()).to.eql(compare);
       state = persistedState.get();
       expect(state).to.have.property(childIndex);
@@ -358,11 +358,11 @@ describe('Persisted State', function () {
 
   describe('mutation', function () {
     it('should not mutate the internal object', function () {
-      let persistedStateValue = { hello: 'world' };
-      let insertedObj = { farewell: 'cruel world' };
-      let persistedState = new PersistedState(persistedStateValue);
+      const persistedStateValue = { hello: 'world' };
+      const insertedObj = { farewell: 'cruel world' };
+      const persistedState = new PersistedState(persistedStateValue);
 
-      let obj = persistedState.get();
+      const obj = persistedState.get();
       _.assign(obj, insertedObj);
 
       expect(obj).to.have.property('farewell');
@@ -379,38 +379,38 @@ describe('Persisted State', function () {
 
     describe('exporting state to JSON', function () {
       it('should return the full JSON representation', function () {
-        let persistedState = new PersistedState(persistedStateValue);
+        const persistedState = new PersistedState(persistedStateValue);
 
-        let json = persistedState.toJSON();
+        const json = persistedState.toJSON();
         expect(json).to.eql(persistedStateValue);
       });
 
       it('should return the JSON representation of the child state', function () {
-        let persistedState = new PersistedState(persistedStateValue);
-        let childState = persistedState.createChild('awesome', { pants: false });
+        const persistedState = new PersistedState(persistedStateValue);
+        const childState = persistedState.createChild('awesome', { pants: false });
 
         expect(childState.toJSON()).to.eql({ pants: false });
         // verify JSON output of the parent state
-        let parentCompare = _.assign({ awesome: { pants: false }}, persistedStateValue);
+        const parentCompare = _.assign({ awesome: { pants: false }}, persistedStateValue);
         expect(persistedState.toJSON()).to.eql(parentCompare);
       });
 
       it('should export stringified version of state', function () {
-        let persistedState = new PersistedState(persistedStateValue);
-        let childState = persistedState.createChild('awesome', { pants: false });
+        const persistedState = new PersistedState(persistedStateValue);
+        const childState = persistedState.createChild('awesome', { pants: false });
 
-        let data = childState.toString();
+        const data = childState.toString();
         expect(JSON.parse(data)).to.eql({ pants: false });
         // verify JSON output of the parent state
-        let parentCompare = _.assign({ awesome: { pants: false }}, persistedStateValue);
+        const parentCompare = _.assign({ awesome: { pants: false }}, persistedStateValue);
         expect(JSON.parse(persistedState.toString())).to.eql(parentCompare);
       });
     });
 
     describe('importing state from JSON string (hydration)', function () {
       it('should set the state from JSON string input', function () {
-        let stateJSON = JSON.stringify(persistedStateValue);
-        let persistedState = new PersistedState();
+        const stateJSON = JSON.stringify(persistedStateValue);
+        const persistedState = new PersistedState();
         expect(persistedState.get()).to.eql({});
 
         persistedState.fromString(stateJSON);
@@ -421,7 +421,7 @@ describe('Persisted State', function () {
 
   describe('get state', function () {
     it('should perform deep gets with various formats', function () {
-      let obj = {
+      const obj = {
         red: {
           green: {
             blue: 'yellow'
@@ -432,7 +432,7 @@ describe('Persisted State', function () {
           violet: ''
         }
       };
-      let persistedState = new PersistedState(obj);
+      const persistedState = new PersistedState(obj);
       expect(persistedState.get()).to.eql(obj);
 
       expect(persistedState.get('red')).to.eql({ green: { blue: 'yellow' } });
@@ -451,7 +451,7 @@ describe('Persisted State', function () {
     });
 
     it('should perform deep gets with arrays', function () {
-      let persistedState = new PersistedState({ hello: { nouns: ['world', 'humans', 'everyone'] } });
+      const persistedState = new PersistedState({ hello: { nouns: ['world', 'humans', 'everyone'] } });
 
       expect(persistedState.get()).to.eql({ hello: { nouns: ['world', 'humans', 'everyone'] } });
       expect(persistedState.get('hello')).to.eql({ nouns: ['world', 'humans', 'everyone'] });
@@ -459,9 +459,9 @@ describe('Persisted State', function () {
     });
 
     it('should pass defaults to parent delegation', function () {
-      let persistedState = new PersistedState({ parent: true });
-      let childState = persistedState.createChild('child', { account: { name: 'first child' }});
-      let defaultValue = 'i have no data';
+      const persistedState = new PersistedState({ parent: true });
+      const childState = persistedState.createChild('child', { account: { name: 'first child' }});
+      const defaultValue = 'i have no data';
 
       expect(childState.get('account.name', defaultValue)).to.eql('first child');
       expect(childState.get('account.age', defaultValue)).to.eql(defaultValue);
@@ -471,25 +471,25 @@ describe('Persisted State', function () {
   describe('set state', function () {
     describe('path format support', function () {
       it('should create deep objects from dot notation', function () {
-        let persistedState = new PersistedState();
+        const persistedState = new PersistedState();
         persistedState.set('one.two.three', 4);
         expect(persistedState.get()).to.eql({ one: { two: { three: 4 } } });
       });
 
       it('should create deep objects from array notation', function () {
-        let persistedState = new PersistedState();
+        const persistedState = new PersistedState();
         persistedState.set('one[two][three]', 4);
         expect(persistedState.get()).to.eql({ one: { two: { three: 4 } } });
       });
 
       it('should create deep objects from arrays', function () {
-        let persistedState = new PersistedState();
+        const persistedState = new PersistedState();
         persistedState.set(['one', 'two', 'three'], 4);
         expect(persistedState.get()).to.eql({ one: { two: { three: 4 } } });
       });
 
       it('should create deep objects with an existing path', function () {
-        let persistedState = new PersistedState({}, 'deep.path');
+        const persistedState = new PersistedState({}, 'deep.path');
         persistedState.set('green[red].blue', 4);
         expect(persistedState.get()).to.eql({ green: { red: { blue: 4 } }});
       });
@@ -555,19 +555,19 @@ describe('Persisted State', function () {
 
   describe('internal state tracking', function () {
     it('should be an empty object', function () {
-      let persistedState = new PersistedState();
+      const persistedState = new PersistedState();
       expect(persistedState._defaultState).to.eql({});
     });
 
     it('should store the default state value', function () {
-      let val = { one: 1, two: 2 };
-      let persistedState = new PersistedState(val);
+      const val = { one: 1, two: 2 };
+      const persistedState = new PersistedState(val);
       expect(persistedState._defaultState).to.eql(val);
     });
 
     it('should keep track of changes', function () {
-      let val = { one: 1, two: 2 };
-      let persistedState = new PersistedState(val);
+      const val = { one: 1, two: 2 };
+      const persistedState = new PersistedState(val);
 
       persistedState.set('two', 22);
       expect(persistedState._defaultState).to.eql(val);
@@ -579,14 +579,14 @@ describe('Persisted State', function () {
     let persistedState;
     let emitter;
 
-    let getByType = function (type, spy) {
+    const getByType = function (type, spy) {
       spy = spy || emitter;
       return spy.getCalls().filter(function (call) {
         return call.args[0] === type;
       });
     };
 
-    let watchEmitter = function (state) {
+    const watchEmitter = function (state) {
       return sinon.spy(state, 'emit');
     };
 
@@ -667,7 +667,7 @@ describe('Persisted State', function () {
     });
 
     it('should emit on parent and child instances', function (done) {
-      let child = persistedState.createChild('checker');
+      const child = persistedState.createChild('checker');
       expect(getByType('change')).to.have.length(0);
 
       // parent and child should emit, set up listener to test
diff --git a/src/ui/public/persisted_state/persisted_state.js b/src/ui/public/persisted_state/persisted_state.js
index 3975c20c24ea6..2df7e511d5ea9 100644
--- a/src/ui/public/persisted_state/persisted_state.js
+++ b/src/ui/public/persisted_state/persisted_state.js
@@ -5,7 +5,7 @@ import SimpleEmitter from 'ui/utils/simple_emitter';
 import EventsProvider from 'ui/events';
 
 export default function (Private) {
-  let Events = Private(EventsProvider);
+  const Events = Private(EventsProvider);
 
   function validateParent(parent, path) {
     if (path.length <= 0) {
@@ -17,7 +17,7 @@ export default function (Private) {
   }
 
   function validateValue(value) {
-    let msg = 'State value must be a plain object';
+    const msg = 'State value must be a plain object';
     if (!value) return;
     if (!_.isPlainObject(value)) throw new errors.PersistedStateError(msg);
   }
@@ -73,21 +73,21 @@ export default function (Private) {
   };
 
   PersistedState.prototype.set = function (key, value) {
-    let params = prepSetParams(key, value, this._path);
-    let val = this._set(params.key, params.value);
+    const params = prepSetParams(key, value, this._path);
+    const val = this._set(params.key, params.value);
     this.emit('set');
     return val;
   };
 
   PersistedState.prototype.setSilent = function (key, value) {
-    let params = prepSetParams(key, value, this._path);
+    const params = prepSetParams(key, value, this._path);
     return this._set(params.key, params.value, true);
   };
 
   PersistedState.prototype.reset = function (path) {
-    let keyPath = this._getIndex(path);
-    let origValue = _.get(this._defaultState, keyPath);
-    let currentValue = _.get(this._mergedState, keyPath);
+    const keyPath = this._getIndex(path);
+    const origValue = _.get(this._defaultState, keyPath);
+    const currentValue = _.get(this._mergedState, keyPath);
 
     if (_.isUndefined(origValue)) {
       this._cleanPath(path, this._mergedState);
@@ -108,7 +108,7 @@ export default function (Private) {
   };
 
   PersistedState.prototype.removeChild = function (path) {
-    let origValue = _.get(this._defaultState, this._getIndex(path));
+    const origValue = _.get(this._defaultState, this._getIndex(path));
 
     if (_.isUndefined(origValue)) {
       this.reset(path);
@@ -139,19 +139,19 @@ export default function (Private) {
   };
 
   PersistedState.prototype._getPartialIndex = function (key) {
-    let keyPath = this._getIndex(key);
+    const keyPath = this._getIndex(key);
     return keyPath.slice(this._path.length);
   };
 
   PersistedState.prototype._cleanPath = function (path, stateTree) {
-    let partialPath = this._getPartialIndex(path);
+    const partialPath = this._getPartialIndex(path);
     let remove = true;
 
     // recursively delete value tree, when no other keys exist
     while (partialPath.length > 0) {
-      let lastKey = partialPath.splice(partialPath.length - 1, 1)[0];
-      let statePath = this._path.concat(partialPath);
-      let stateVal = statePath.length > 0 ? _.get(stateTree, statePath) : stateTree;
+      const lastKey = partialPath.splice(partialPath.length - 1, 1)[0];
+      const statePath = this._path.concat(partialPath);
+      const stateVal = statePath.length > 0 ? _.get(stateTree, statePath) : stateTree;
 
       // if stateVal isn't an object, do nothing
       if (!_.isPlainObject(stateVal)) return;
@@ -162,13 +162,13 @@ export default function (Private) {
   };
 
   PersistedState.prototype._getDefault = function () {
-    let def = (this._hasPath()) ? undefined : {};
+    const def = (this._hasPath()) ? undefined : {};
     return (this._parent ? this.get() : def);
   };
 
   PersistedState.prototype._setPath = function (path) {
-    let isString = _.isString(path);
-    let isArray = _.isArray(path);
+    const isString = _.isString(path);
+    const isArray = _.isArray(path);
 
     if (!isString && !isArray) return [];
     return (isString) ? [this._getIndex(path)] : path;
@@ -196,11 +196,11 @@ export default function (Private) {
   };
 
   PersistedState.prototype._set = function (key, value, silent, initialChildState) {
-    let self = this;
+    const self = this;
     let stateChanged = false;
-    let initialState = !this._initialized;
-    let keyPath = this._getIndex(key);
-    let hasKeyPath = keyPath.length > 0;
+    const initialState = !this._initialized;
+    const keyPath = this._getIndex(key);
+    const hasKeyPath = keyPath.length > 0;
 
     // if this is the initial state value, save value as the default
     if (initialState) {
@@ -226,7 +226,7 @@ export default function (Private) {
         }
       } else {
         // check for changes at path, emit an event when different
-        let curVal = hasKeyPath ? this.get(keyPath) : this._mergedState;
+        const curVal = hasKeyPath ? this.get(keyPath) : this._mergedState;
         stateChanged = !_.isEqual(curVal, value);
 
         if (!initialChildState) {
@@ -243,11 +243,11 @@ export default function (Private) {
     }
 
     // update the merged state value
-    let targetObj = this._mergedState || _.cloneDeep(this._defaultState);
-    let sourceObj = _.merge({}, this._defaultChildState, this._changedState);
+    const targetObj = this._mergedState || _.cloneDeep(this._defaultState);
+    const sourceObj = _.merge({}, this._defaultChildState, this._changedState);
 
     // handler arguments are (targetValue, sourceValue, key, target, source)
-    let mergeMethod = function (targetValue, sourceValue, mergeKey) {
+    const mergeMethod = function (targetValue, sourceValue, mergeKey) {
       // if not initial state, skip default merge method (ie. return value, see note below)
       if (!initialState && !initialChildState && _.isEqual(keyPath, self._getIndex(mergeKey))) {
         // use the sourceValue or fall back to targetValue
diff --git a/src/ui/public/private/__tests__/private.js b/src/ui/public/private/__tests__/private.js
index fc3dab39d3436..0efb5ac1fc110 100644
--- a/src/ui/public/private/__tests__/private.js
+++ b/src/ui/public/private/__tests__/private.js
@@ -11,12 +11,12 @@ describe('Private module loader', function () {
   }));
 
   it('accepts a provider that will be called to init a module', function () {
-    let football = {};
+    const football = {};
     function Provider() {
       return football;
     }
 
-    let instance = Private(Provider);
+    const instance = Private(Provider);
     expect(instance).to.be(football);
   });
 
@@ -25,25 +25,25 @@ describe('Private module loader', function () {
       return Private;
     }
 
-    let instance = Private(Provider);
+    const instance = Private(Provider);
     expect(instance).to.be(Private);
   });
 
   it('detects circular dependencies', function () {
     expect(function () {
       function Provider1() {
-        let p3 = Private(Provider3);
+        const p3 = Private(Provider3);
       }
 
       function Provider2() {
-        let p3 = Private(Provider3);
+        const p3 = Private(Provider3);
       }
 
       function Provider3() {
-        let p1 = Private(Provider3);
+        const p1 = Private(Provider3);
       }
 
-      let p1 = Private(Provider1);
+      const p1 = Private(Provider1);
     }).to.throwException(/circular/i);
   });
 
@@ -57,24 +57,24 @@ describe('Private module loader', function () {
 
   describe('#stub', function () {
     it('accepts a replacement instance for a Provider', function () {
-      let replaced = {};
-      let replacement = {};
+      const replaced = {};
+      const replacement = {};
 
       function Provider() {
         return replaced;
       }
 
-      let instance = Private(Provider);
+      const instance = Private(Provider);
       expect(instance).to.be(replaced);
 
       Private.stub(Provider, replacement);
 
-      let instance2 = Private(Provider);
+      const instance2 = Private(Provider);
       expect(instance2).to.be(replacement);
 
       Private.stub(Provider, replaced);
 
-      let instance3 = Private(Provider);
+      const instance3 = Private(Provider);
       expect(instance3).to.be(replaced);
     });
   });
@@ -89,18 +89,18 @@ describe('Private module loader', function () {
         return {};
       }
 
-      let instance1 = Private(Provider1);
+      const instance1 = Private(Provider1);
       expect(instance1).to.be.an('object');
 
       Private.swap(Provider1, Provider2);
 
-      let instance2 = Private(Provider1);
+      const instance2 = Private(Provider1);
       expect(instance2).to.be.an('object');
       expect(instance2).to.not.be(instance1);
 
       Private.swap(Provider1, Provider1);
 
-      let instance3 = Private(Provider1);
+      const instance3 = Private(Provider1);
       expect(instance3).to.be(instance1);
     });
 
@@ -115,12 +115,12 @@ describe('Private module loader', function () {
         };
       }
 
-      let instance1 = Private(Provider1);
+      const instance1 = Private(Provider1);
       expect(instance1).to.be.an('object');
 
       Private.swap(Provider1, Provider2);
 
-      let instance2 = Private(Provider1);
+      const instance2 = Private(Provider1);
       expect(instance2).to.have.property('instance1');
       expect(instance2.instance1).to.be(instance1);
     });
diff --git a/src/ui/public/private/private.js b/src/ui/public/private/private.js
index 4c371da82cc47..9359fd8f9e6d7 100644
--- a/src/ui/public/private/private.js
+++ b/src/ui/public/private/private.js
@@ -87,7 +87,7 @@ import uiModules from 'ui/modules';
  */
 
 
-let nextId = _.partial(_.uniqueId, 'privateProvider#');
+const nextId = _.partial(_.uniqueId, 'privateProvider#');
 
 function name(fn) {
   return fn.name || fn.toString().split('\n').shift();
@@ -95,11 +95,11 @@ function name(fn) {
 
 uiModules.get('kibana')
 .provider('Private', function () {
-  let provider = this;
+  const provider = this;
 
   // one cache/swaps per Provider
-  let cache = {};
-  let swaps = {};
+  const cache = {};
+  const swaps = {};
 
   // return the uniq id for this function
   function identify(fn) {
@@ -117,15 +117,15 @@ uiModules.get('kibana')
   };
 
   provider.swap = function (fn, prov) {
-    let id = identify(fn);
+    const id = identify(fn);
     swaps[id] = prov;
   };
 
   provider.$get = ['$injector', function PrivateFactory($injector) {
 
     // prevent circular deps by tracking where we came from
-    let privPath = [];
-    let pathToString = function () {
+    const privPath = [];
+    const pathToString = function () {
       return privPath.map(name).join(' -> ');
     };
 
@@ -140,7 +140,7 @@ uiModules.get('kibana')
 
       privPath.push(prov);
 
-      let context = {};
+      const context = {};
       let instance = $injector.invoke(prov, context, locals);
       if (!_.isObject(instance)) instance = context;
 
diff --git a/src/ui/public/promises/__tests__/promises.js b/src/ui/public/promises/__tests__/promises.js
index 9ded576e76cf3..f623e54da5f64 100644
--- a/src/ui/public/promises/__tests__/promises.js
+++ b/src/ui/public/promises/__tests__/promises.js
@@ -31,8 +31,8 @@ describe('Promise service', function () {
     });
 
     it('rejects if the callback receives an error', function () {
-      let errback = sinon.stub();
-      let err = new Error();
+      const errback = sinon.stub();
+      const err = new Error();
       Promise.fromNode(cb => cb(err)).catch(errback);
       $rootScope.$apply();
 
@@ -41,8 +41,8 @@ describe('Promise service', function () {
     });
 
     it('resolves with the second argument', function () {
-      let thenback = sinon.stub();
-      let result = {};
+      const thenback = sinon.stub();
+      const result = {};
       Promise.fromNode(cb => cb(null, result)).then(thenback);
       $rootScope.$apply();
 
@@ -51,9 +51,9 @@ describe('Promise service', function () {
     });
 
     it('resolves with an array if multiple arguments are received', function () {
-      let thenback = sinon.stub();
-      let result1 = {};
-      let result2 = {};
+      const thenback = sinon.stub();
+      const result1 = {};
+      const result2 = {};
       Promise.fromNode(cb => cb(null, result1, result2)).then(thenback);
       $rootScope.$apply();
 
@@ -63,7 +63,7 @@ describe('Promise service', function () {
     });
 
     it('resolves with an array if multiple undefined are received', function () {
-      let thenback = sinon.stub();
+      const thenback = sinon.stub();
       Promise.fromNode(cb => cb(null, undefined, undefined)).then(thenback);
       $rootScope.$apply();
 
diff --git a/src/ui/public/promises/promises.js b/src/ui/public/promises/promises.js
index a2d1ef5249c28..8e3ed9c0b3f17 100644
--- a/src/ui/public/promises/promises.js
+++ b/src/ui/public/promises/promises.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import uiModules from 'ui/modules';
 
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 // Provides a tiny subset of the excelent API from
 // bluebird, reimplemented using the $q service
@@ -9,7 +9,7 @@ module.service('Promise', function ($q, $timeout) {
   function Promise(fn) {
     if (typeof this === 'undefined') throw new Error('Promise constructor must be called with "new"');
 
-    let defer = $q.defer();
+    const defer = $q.defer();
     try {
       fn(defer.resolve, defer.reject);
     } catch (e) {
@@ -20,12 +20,12 @@ module.service('Promise', function ($q, $timeout) {
 
   Promise.all = Promise.props = $q.all;
   Promise.resolve = function (val) {
-    let defer = $q.defer();
+    const defer = $q.defer();
     defer.resolve(val);
     return defer.promise;
   };
   Promise.reject = function (reason) {
-    let defer = $q.defer();
+    const defer = $q.defer();
     defer.reject(reason);
     return defer.promise;
   };
@@ -36,7 +36,7 @@ module.service('Promise', function ($q, $timeout) {
   };
   Promise.method = function (fn) {
     return function () {
-      let args = Array.prototype.slice.call(arguments);
+      const args = Array.prototype.slice.call(arguments);
       return Promise.try(fn, args, this);
     };
   };
@@ -51,7 +51,7 @@ module.service('Promise', function ($q, $timeout) {
     }));
   };
   Promise.each = function (arr, fn) {
-    let queue = arr.slice(0);
+    const queue = arr.slice(0);
     let i = 0;
     return (function next() {
       if (!queue.length) return arr;
@@ -64,7 +64,7 @@ module.service('Promise', function ($q, $timeout) {
     return obj && typeof obj.then === 'function';
   };
   Promise.halt = _.once(function () {
-    let promise = new Promise();
+    const promise = new Promise();
     promise.then = _.constant(promise);
     promise.catch = _.constant(promise);
     return promise;
@@ -155,7 +155,7 @@ module.factory('PromiseEmitter', function (Promise) {
    * @return {Promise}
    */
   function PromiseEmitter(fn, handler) {
-    let prom = new Promise(fn);
+    const prom = new Promise(fn);
 
     if (!handler) return prom;
 
diff --git a/src/ui/public/reflow_watcher/__tests__/reflow_watcher.js b/src/ui/public/reflow_watcher/__tests__/reflow_watcher.js
index 576fa9f0bd9ae..1b1f8bafba505 100644
--- a/src/ui/public/reflow_watcher/__tests__/reflow_watcher.js
+++ b/src/ui/public/reflow_watcher/__tests__/reflow_watcher.js
@@ -8,11 +8,11 @@ import EventsProvider from 'ui/events';
 import ReflowWatcherProvider from 'ui/reflow_watcher';
 describe('Reflow watcher', function () {
 
-  let $body = $(document.body);
-  let $window = $(window);
-  let expectStubbedEventAndEl = function (stub, event, $el) {
+  const $body = $(document.body);
+  const $window = $(window);
+  const expectStubbedEventAndEl = function (stub, event, $el) {
     expect(stub.getCalls().some(function (call) {
-      let events = call.args[0].split(' ');
+      const events = call.args[0].split(' ');
       return _.contains(events, event) && $el.is(call.thisValue);
     })).to.be(true);
   };
@@ -70,7 +70,7 @@ describe('Reflow watcher', function () {
   });
 
   it('triggers the "reflow" event within a new angular tick', function () {
-    let stub = sinon.stub();
+    const stub = sinon.stub();
     reflowWatcher.on('reflow', stub);
     reflowWatcher.trigger();
 
diff --git a/src/ui/public/reflow_watcher/reflow_watcher.js b/src/ui/public/reflow_watcher/reflow_watcher.js
index 2592cc9e4bc12..d825e94d9c7e5 100644
--- a/src/ui/public/reflow_watcher/reflow_watcher.js
+++ b/src/ui/public/reflow_watcher/reflow_watcher.js
@@ -4,12 +4,12 @@ import _ from 'lodash';
 import EventsProvider from 'ui/events';
 export default function ReflowWatcherService(Private, $rootScope, $http) {
 
-  let EventEmitter = Private(EventsProvider);
-  let $body = $(document.body);
-  let $window = $(window);
+  const EventEmitter = Private(EventsProvider);
+  const $body = $(document.body);
+  const $window = $(window);
 
-  let MOUSE_EVENTS = 'mouseup';
-  let WINDOW_EVENTS = 'resize';
+  const MOUSE_EVENTS = 'mouseup';
+  const WINDOW_EVENTS = 'resize';
 
   _.class(ReflowWatcher).inherits(EventEmitter);
   /**
diff --git a/src/ui/public/registry/__tests__/index.js b/src/ui/public/registry/__tests__/index.js
index 85091d32bc754..aaf1f69b115b5 100644
--- a/src/ui/public/registry/__tests__/index.js
+++ b/src/ui/public/registry/__tests__/index.js
@@ -13,14 +13,14 @@ describe('Registry', function () {
   }));
 
   it('is technically a function', function () {
-    let reg = registry();
+    const reg = registry();
     expect(reg).to.be.a('function');
   });
 
   describe('#register', function () {
     it('accepts a Private module', function () {
-      let reg = registry();
-      let mod = function SomePrivateModule() {};
+      const reg = registry();
+      const mod = function SomePrivateModule() {};
 
       reg.register(mod);
       // modules are not exposed, so this is the most that we can test
@@ -29,13 +29,13 @@ describe('Registry', function () {
 
   describe('as a module', function () {
     it('exposes the list of registered modules', function () {
-      let reg = registry();
-      let mod = function SomePrivateModule(Private) {
+      const reg = registry();
+      const mod = function SomePrivateModule(Private) {
         this.PrivateModuleLoader = Private;
       };
 
       reg.register(mod);
-      let modules = Private(reg);
+      const modules = Private(reg);
       expect(modules).to.have.length(1);
       expect(modules[0]).to.have.property('PrivateModuleLoader', Private);
     });
@@ -43,16 +43,16 @@ describe('Registry', function () {
 
   describe('spec', function () {
     it('executes with the module list as "this", and can override it', function () {
-      let i = 0;
+      const i = 0;
       let self;
 
-      let reg = registry({
+      const reg = registry({
         constructor: function () {
           return { mods: (self = this) };
         }
       });
 
-      let modules = Private(reg);
+      const modules = Private(reg);
       expect(modules).to.be.an('object');
       expect(modules).to.have.property('mods', self);
     });
@@ -60,7 +60,7 @@ describe('Registry', function () {
 
   describe('spec.name', function () {
     it('sets the displayName of the registry and the name param on the final instance', function () {
-      let reg = registry({
+      const reg = registry({
         name: 'visTypes'
       });
 
@@ -72,27 +72,27 @@ describe('Registry', function () {
   describe('spec.constructor', function () {
     it('executes before the modules are returned', function () {
       let i = 0;
-      let reg = registry({
+      const reg = registry({
         constructor: function () {
           i = i + 1;
         }
       });
 
-      let modules = Private(reg);
+      const modules = Private(reg);
       expect(i).to.be(1);
     });
 
     it('executes with the module list as "this", and can override it', function () {
-      let i = 0;
+      const i = 0;
       let self;
 
-      let reg = registry({
+      const reg = registry({
         constructor: function () {
           return { mods: (self = this) };
         }
       });
 
-      let modules = Private(reg);
+      const modules = Private(reg);
       expect(modules).to.be.an('object');
       expect(modules).to.have.property('mods', self);
     });
@@ -100,13 +100,13 @@ describe('Registry', function () {
 
   describe('spec[any]', function () {
     it('mixes the extra properties into the module list', function () {
-      let reg = registry({
+      const reg = registry({
         someMethod: function () {
           return this;
         }
       });
 
-      let modules = Private(reg);
+      const modules = Private(reg);
       expect(modules).to.have.property('someMethod');
       expect(modules.someMethod()).to.be(modules);
     });
diff --git a/src/ui/public/registry/_registry.js b/src/ui/public/registry/_registry.js
index 396ad08237ed8..c5aa8ec454bc2 100644
--- a/src/ui/public/registry/_registry.js
+++ b/src/ui/public/registry/_registry.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import IndexedArray from 'ui/indexed_array';
 import RegistryVisTypesProvider from 'ui/registry/vis_types';
-let notPropsOptNames = IndexedArray.OPT_NAMES.concat('constructor');
+const notPropsOptNames = IndexedArray.OPT_NAMES.concat('constructor');
 
 /**
  * Create a registry, which is just a Private module provider.
@@ -49,10 +49,10 @@ let notPropsOptNames = IndexedArray.OPT_NAMES.concat('constructor');
 export default function createRegistry(spec) {
   spec = spec || {};
 
-  let constructor = _.has(spec, 'constructor') && spec.constructor;
-  let iaOpts = _.defaults(_.pick(spec, IndexedArray.OPT_NAMES), { index: ['name'] });
-  let props = _.omit(spec, notPropsOptNames);
-  let providers = [];
+  const constructor = _.has(spec, 'constructor') && spec.constructor;
+  const iaOpts = _.defaults(_.pick(spec, IndexedArray.OPT_NAMES), { index: ['name'] });
+  const props = _.omit(spec, notPropsOptNames);
+  const providers = [];
 
   /**
    * This is the Private module that will be instanciated by
@@ -62,7 +62,7 @@ export default function createRegistry(spec) {
    *                          that were registered, the registry spec
    *                          defines how things will be indexed.
    */
-  let registry = function (Private, $injector) {
+  const registry = function (Private, $injector) {
     // index all of the modules
     iaOpts.initialSet = providers.map(Private);
     let modules = new IndexedArray(iaOpts);
diff --git a/src/ui/public/registry/field_formats.js b/src/ui/public/registry/field_formats.js
index ca7895faca82f..393f2660afb47 100644
--- a/src/ui/public/registry/field_formats.js
+++ b/src/ui/public/registry/field_formats.js
@@ -7,7 +7,7 @@ export default uiRegistry({
   group: ['fieldType'],
 
   constructor: function (config) {
-    let self = this;
+    const self = this;
     let defaultMap;
 
     function init() {
@@ -54,7 +54,7 @@ export default uiRegistry({
      * @return {FieldFormat}
      */
     self.getInstance = _.memoize(function (formatId) {
-      let FieldFormat = self.byId[formatId];
+      const FieldFormat = self.byId[formatId];
       return new FieldFormat();
     });
 
@@ -65,8 +65,8 @@ export default uiRegistry({
      * @return {FieldFormat}
      */
     self.getDefaultInstance = _.memoize(function (fieldType) {
-      let conf = self.getDefaultConfig(fieldType);
-      let FieldFormat = self.byId[conf.id];
+      const conf = self.getDefaultConfig(fieldType);
+      const FieldFormat = self.byId[conf.id];
       return new FieldFormat(conf.params);
     });
 
diff --git a/src/ui/public/routes/__tests__/_route_manager.js b/src/ui/public/routes/__tests__/_route_manager.js
index c854d88325400..b920e5d63dd14 100644
--- a/src/ui/public/routes/__tests__/_route_manager.js
+++ b/src/ui/public/routes/__tests__/_route_manager.js
@@ -5,7 +5,7 @@ import RouteManager from 'ui/routes/route_manager';
 import expect from 'expect.js';
 
 let routes; // will contain an new instance of RouteManager for each test
-let chainableMethods = [
+const chainableMethods = [
   { name: 'when', args: ['', {}] },
   { name: 'otherwise', args: [{}] },
   { name: 'defaults', args: [/regexp/, {}] }
@@ -31,7 +31,7 @@ describe('routes/route_manager', function () {
 
   describe('#otherwise', function () {
     it('should forward the last otherwise route', function () {
-      let otherRoute = {};
+      const otherRoute = {};
       routes.otherwise({});
       routes.otherwise(otherRoute);
 
@@ -68,7 +68,7 @@ describe('routes/route_manager', function () {
 
   describe('#config', function () {
     it('should add defined routes to the global $routeProvider service in order', function () {
-      let args = [
+      const args = [
         ['/one', {}],
         ['/two', {}]
       ];
@@ -81,8 +81,8 @@ describe('routes/route_manager', function () {
 
       expect($rp.when.callCount).to.be(args.length);
       _.times(args.length, function (i) {
-        let call = $rp.when.getCall(i);
-        let a = args.shift();
+        const call = $rp.when.getCall(i);
+        const a = args.shift();
 
         expect(call.args[0]).to.be(a[0]);
         expect(call.args[1]).to.be(a[1]);
diff --git a/src/ui/public/routes/__tests__/_work_queue.js b/src/ui/public/routes/__tests__/_work_queue.js
index 863f7345075bd..33044daeae835 100644
--- a/src/ui/public/routes/__tests__/_work_queue.js
+++ b/src/ui/public/routes/__tests__/_work_queue.js
@@ -25,10 +25,10 @@ describe('work queue', function () {
 
   describe('#resolveWhenFull', function () {
     it('resolves requests waiting for the queue to fill when appropriate', function () {
-      let size = _.random(5, 50);
+      const size = _.random(5, 50);
       queue.limit = size;
 
-      let whenFull = Promise.defer();
+      const whenFull = Promise.defer();
       sinon.stub(whenFull, 'resolve');
       queue.resolveWhenFull(whenFull);
 
@@ -53,11 +53,11 @@ describe('work queue', function () {
    *                         can manipulate the filled queue
    */
   function fillWithStubs(then) {
-    let size = _.random(5, 50);
-    let stub = sinon.stub();
+    const size = _.random(5, 50);
+    const stub = sinon.stub();
 
     _.times(size, function () {
-      let d = Promise.defer();
+      const d = Promise.defer();
       // overwrite the defer methods with the stub
       d.resolve = stub;
       d.reject = stub;
diff --git a/src/ui/public/routes/__tests__/_wrap_route_with_prep.js b/src/ui/public/routes/__tests__/_wrap_route_with_prep.js
index a56cb503e1d46..8570b3f7cb8c3 100644
--- a/src/ui/public/routes/__tests__/_wrap_route_with_prep.js
+++ b/src/ui/public/routes/__tests__/_wrap_route_with_prep.js
@@ -18,11 +18,11 @@ describe('wrapRouteWithPrep fn', function () {
     routes = new RouteManager();
   });
 
-  let SchedulingTest = function (opts) {
+  const SchedulingTest = function (opts) {
     opts = opts || {};
 
-    let delaySetup = opts.delayUserWork ? 0 : 50;
-    let delayUserWork = opts.delayUserWork ? 50 : 0;
+    const delaySetup = opts.delayUserWork ? 0 : 50;
+    const delayUserWork = opts.delayUserWork ? 50 : 0;
 
     return function () {
       ngMock.module('kibana', 'kibana/notify');
diff --git a/src/ui/public/routes/route_manager.js b/src/ui/public/routes/route_manager.js
index e06c9fc6e55d5..22c6c1e518387 100644
--- a/src/ui/public/routes/route_manager.js
+++ b/src/ui/public/routes/route_manager.js
@@ -4,16 +4,16 @@ import wrapRouteWithPrep from './wrap_route_with_prep';
 import RouteSetupManager from './route_setup_manager';
 
 function RouteManager() {
-  let self = this;
-  let setup = new RouteSetupManager();
-  let when = [];
-  let defaults = [];
+  const self = this;
+  const setup = new RouteSetupManager();
+  const when = [];
+  const defaults = [];
   let otherwise;
 
   self.config = function ($routeProvider) {
     when.forEach(function (args) {
-      let path = args[0];
-      let route = args[1] || {};
+      const path = args[0];
+      const route = args[1] || {};
 
       // merge in any defaults
       defaults.forEach(function (args) {
@@ -40,7 +40,7 @@ function RouteManager() {
     }
   };
 
-  let wrapSetupAndChain = (fn, ...args) => {
+  const wrapSetupAndChain = (fn, ...args) => {
     fn.apply(setup, args);
     return this;
   };
diff --git a/src/ui/public/routes/route_setup_manager.js b/src/ui/public/routes/route_setup_manager.js
index 1cb89fe456455..15ab1b264149f 100644
--- a/src/ui/public/routes/route_setup_manager.js
+++ b/src/ui/public/routes/route_setup_manager.js
@@ -30,7 +30,7 @@ module.exports = class RouteSetupManager {
    */
   doWork(Promise, $injector, userWork) {
 
-    let invokeEach = (arr, locals) => {
+    const invokeEach = (arr, locals) => {
       return Promise.map(arr, fn => {
         if (!fn) return;
         return $injector.invoke(fn, null, locals);
@@ -39,16 +39,16 @@ module.exports = class RouteSetupManager {
 
     // call each error handler in order, until one of them resolves
     // or we run out of handlers
-    let callErrorHandlers = (handlers, origError) => {
+    const callErrorHandlers = (handlers, origError) => {
       if (!_.size(handlers)) throw origError;
 
       // clone so we don't discard handlers or loose them
       handlers = handlers.slice(0);
 
-      let next = (err) => {
+      const next = (err) => {
         if (!handlers.length) throw err;
 
-        let handler = handlers.shift();
+        const handler = handlers.shift();
         if (!handler) return next(err);
 
         return Promise.try(function () {
@@ -66,7 +66,7 @@ module.exports = class RouteSetupManager {
     )
     .then(() => {
       // wait for the queue to fill up, then do all the work
-      let defer = Promise.defer();
+      const defer = Promise.defer();
       userWork.resolveWhenFull(defer);
 
       return defer.promise.then(() => Promise.all(userWork.doWork()));
diff --git a/src/ui/public/routes/routes.js b/src/ui/public/routes/routes.js
index cbb9878df7a1e..077590cafa642 100644
--- a/src/ui/public/routes/routes.js
+++ b/src/ui/public/routes/routes.js
@@ -1,7 +1,7 @@
 import RouteManager from './route_manager';
 import 'angular-route/angular-route';
 import uiModules from 'ui/modules';
-let defaultRouteManager = new RouteManager();
+const defaultRouteManager = new RouteManager();
 
 module.exports = {
   ...defaultRouteManager,
diff --git a/src/ui/public/routes/work_queue.js b/src/ui/public/routes/work_queue.js
index 40f4294327829..05146f6613a07 100644
--- a/src/ui/public/routes/work_queue.js
+++ b/src/ui/public/routes/work_queue.js
@@ -1,10 +1,10 @@
 import _ from 'lodash';
 
 function WorkQueue() {
-  let q = this;
+  const q = this;
 
-  let work = [];
-  let fullDefers = [];
+  const work = [];
+  const fullDefers = [];
 
   q.limit = 0;
   Object.defineProperty(q, 'length', {
@@ -13,13 +13,13 @@ function WorkQueue() {
     }
   });
 
-  let resolve = function (defers) {
+  const resolve = function (defers) {
     return defers.splice(0).map(function (defer) {
       return defer.resolve();
     });
   };
 
-  let checkIfFull = function () {
+  const checkIfFull = function () {
     if (work.length >= q.limit && fullDefers.length) {
       resolve(fullDefers);
     }
@@ -31,7 +31,7 @@ function WorkQueue() {
   };
 
   q.doWork = function () {
-    let resps = resolve(work);
+    const resps = resolve(work);
     checkIfFull();
     return resps;
   };
diff --git a/src/ui/public/routes/wrap_route_with_prep.js b/src/ui/public/routes/wrap_route_with_prep.js
index 5c4b98a82d0a8..6ed3368226af3 100644
--- a/src/ui/public/routes/wrap_route_with_prep.js
+++ b/src/ui/public/routes/wrap_route_with_prep.js
@@ -7,11 +7,11 @@ import errors from 'ui/errors';
 function wrapRouteWithPrep(route, setup) {
   if (!route.resolve && route.redirectTo) return;
 
-  let userWork = new WorkQueue();
+  const userWork = new WorkQueue();
   // the point at which we will consider the queue "full"
   userWork.limit = _.keys(route.resolve).length;
 
-  let resolve = {
+  const resolve = {
     __prep__: function ($injector) {
       return $injector.invoke(setup.doWork, setup, { userWork });
     }
@@ -21,7 +21,7 @@ function wrapRouteWithPrep(route, setup) {
   // prep is complete
   _.forOwn(route.resolve || {}, function (expr, name) {
     resolve[name] = function ($injector, Promise) {
-      let defer = Promise.defer();
+      const defer = Promise.defer();
       userWork.push(defer);
       return defer.promise.then(function () {
         return $injector[angular.isString(expr) ? 'get' : 'invoke'](expr);
diff --git a/src/ui/public/stack_trace_mapper/set_error_stack.js b/src/ui/public/stack_trace_mapper/set_error_stack.js
index ff6f5b7838455..47e3dacb8aeb0 100644
--- a/src/ui/public/stack_trace_mapper/set_error_stack.js
+++ b/src/ui/public/stack_trace_mapper/set_error_stack.js
@@ -1,6 +1,6 @@
 import _ from 'lodash';
 
-let err = new Error();
+const err = new Error();
 try { setByAssignment(err, 'john'); } catch (e) {} // eslint-disable-line
 
 // err.stack is not always writeable, so we
@@ -13,7 +13,7 @@ if (err.stack === 'john') module.exports = setByAssignment;
 else module.exports = setByShadowing;
 
 function setByShadowing(err, stack) {
-  let props = _.mapValues(err, function (val) {
+  const props = _.mapValues(err, function (val) {
     return {
       enumerable: true,
       value: val
diff --git a/src/ui/public/stack_trace_mapper/stack_line_format.js b/src/ui/public/stack_trace_mapper/stack_line_format.js
index 7d4c2ebe476c7..aed9949777008 100644
--- a/src/ui/public/stack_trace_mapper/stack_line_format.js
+++ b/src/ui/public/stack_trace_mapper/stack_line_format.js
@@ -1,6 +1,6 @@
 import _ from 'lodash';
 
-let opts = [
+const opts = [
   /@((?:[!#$&-;=?-\[\]_a-z~]|%[0-9a-f]{2})+\.js)\:(\d+)(?:\:(\d+)|())/ig,
   /(?: \(|at )((?:[!#$&-;=?-\[\]_a-z~]|%[0-9a-f]{2})+\.js)\:(\d+)(?:\:(\d+)|())/ig
 ];
@@ -8,7 +8,7 @@ let opts = [
 let sample;
 try { throw new Error('msg'); } catch (e) { sample = e.stack; }
 
-let format = _.find(opts, function (format) {
+const format = _.find(opts, function (format) {
   return format.test(sample);
 });
 
diff --git a/src/ui/public/stack_trace_mapper/stack_trace_mapper.js b/src/ui/public/stack_trace_mapper/stack_trace_mapper.js
index 85b4366184333..348de16e1d99e 100644
--- a/src/ui/public/stack_trace_mapper/stack_trace_mapper.js
+++ b/src/ui/public/stack_trace_mapper/stack_trace_mapper.js
@@ -22,7 +22,7 @@ StackTraceMapper.prototype.init = function (mapUrls) {
 StackTraceMapper.prototype.mapError = function (err) {
   if (!stackLineFormat || !err.stack) return err;
 
-  let stack = err.stack.replace(stackLineFormat, this.mapLine);
+  const stack = err.stack.replace(stackLineFormat, this.mapLine);
   return setErrorStack(err, stack);
 };
 
@@ -39,10 +39,10 @@ StackTraceMapper.prototype.getMapFor = function (url) {
 StackTraceMapper.prototype.loadMaps = function (mapUrls) {
   mapUrls = _.clone(mapUrls || {});
 
-  let maps = this.maps;
+  const maps = this.maps;
 
   $('script[src][src-map]').each(function () {
-    let $el = $(this);
+    const $el = $(this);
     mapUrls[$el.attr('src')] = $el.attr('src-map');
   });
 
diff --git a/src/ui/public/stack_trace_mapper/translate_stack_line.js b/src/ui/public/stack_trace_mapper/translate_stack_line.js
index f19f64cfe6186..c2a2c313a9a44 100644
--- a/src/ui/public/stack_trace_mapper/translate_stack_line.js
+++ b/src/ui/public/stack_trace_mapper/translate_stack_line.js
@@ -3,16 +3,16 @@ import _ from 'lodash';
 module.exports = function (map, match, filename, line, col) {
   if (!map) return match;
 
-  let position = {
+  const position = {
     line: parseFloat(line) || 0,
     column: parseFloat(col) || 0
   };
 
-  let srcPosition = map.smc.originalPositionFor(position);
+  const srcPosition = map.smc.originalPositionFor(position);
   if (!srcPosition || !srcPosition.source) return match;
 
-  let srcFilename = srcPosition.source;
-  let srcLine = srcPosition.line;
+  const srcFilename = srcPosition.source;
+  const srcLine = srcPosition.line;
   let srcCol = srcPosition.column;
 
   if (srcCol === 0 && position.column) {
@@ -28,8 +28,8 @@ module.exports = function (map, match, filename, line, col) {
   // we don't accidentally replace the wrong part we use splitting and consumption
   let resp = '';
   let remainingResp = match;
-  let fold = function (replace, replacement) {
-    let wrappingContent = remainingResp.split(replace);
+  const fold = function (replace, replacement) {
+    const wrappingContent = remainingResp.split(replace);
     resp += wrappingContent.shift() + replacement;
     remainingResp = wrappingContent.join(replace);
   };
diff --git a/src/ui/public/state_management/__tests__/app_state.js b/src/ui/public/state_management/__tests__/app_state.js
index 6f9af310db4a4..ba4b1310a0f70 100644
--- a/src/ui/public/state_management/__tests__/app_state.js
+++ b/src/ui/public/state_management/__tests__/app_state.js
@@ -27,7 +27,7 @@ describe('State Management', function () {
     });
 
     it('should use passed in params', function () {
-      let params = {
+      const params = {
         test: true,
         mock: false
       };
@@ -46,8 +46,8 @@ describe('State Management', function () {
     });
 
     it('should be destroyed on $routeChangeStart', function () {
-      let destroySpy = sinon.spy(appState, 'destroy');
-      let url = '/test/path';
+      const destroySpy = sinon.spy(appState, 'destroy');
+      const url = '/test/path';
 
       $rootScope.$emit('$routeChangeStart');
 
diff --git a/src/ui/public/state_management/__tests__/state.js b/src/ui/public/state_management/__tests__/state.js
index d0233594e5b44..7224be9cc4623 100644
--- a/src/ui/public/state_management/__tests__/state.js
+++ b/src/ui/public/state_management/__tests__/state.js
@@ -23,26 +23,26 @@ describe('State Management', function () {
 
   describe('Provider', function () {
     it('should reset the state to the defaults', function () {
-      let state = new State('_s', { message: ['test'] });
+      const state = new State('_s', { message: ['test'] });
       state.reset();
-      let search = $location.search();
+      const search = $location.search();
       expect(search).to.have.property('_s');
       expect(search._s).to.equal('(message:!(test))');
       expect(state.message).to.eql(['test']);
     });
 
     it('should apply the defaults upon initialization', function () {
-      let state = new State('_s', { message: 'test' });
+      const state = new State('_s', { message: 'test' });
       expect(state).to.have.property('message', 'test');
     });
 
     it('should inherit from Events', function () {
-      let state = new State();
+      const state = new State();
       expect(state).to.be.an(Events);
     });
 
     it('should emit an event if reset with changes', function (done) {
-      let state = new State('_s', { message: 'test' });
+      const state = new State('_s', { message: 'test' });
       state.on('reset_with_changes', function (keys) {
         expect(keys).to.eql(['message']);
         done();
@@ -54,7 +54,7 @@ describe('State Management', function () {
     });
 
     it('should not emit an event if reset without changes', function () {
-      let state = new State('_s', { message: 'test' });
+      const state = new State('_s', { message: 'test' });
       state.on('reset_with_changes', function () {
         expect().fail();
       });
@@ -67,29 +67,29 @@ describe('State Management', function () {
 
   describe('Search', function () {
     it('should save to $location.search()', function () {
-      let state = new State('_s', { test: 'foo' });
+      const state = new State('_s', { test: 'foo' });
       state.save();
-      let search = $location.search();
+      const search = $location.search();
       expect(search).to.have.property('_s');
       expect(search._s).to.equal('(test:foo)');
     });
 
     it('should emit an event if changes are saved', function (done) {
-      let state = new State();
+      const state = new State();
       state.on('save_with_changes', function (keys) {
         expect(keys).to.eql(['test']);
         done();
       });
       state.test = 'foo';
       state.save();
-      let search = $location.search();
+      const search = $location.search();
       $rootScope.$apply();
     });
   });
 
   describe('Fetch', function () {
     it('should emit an event if changes are fetched', function (done) {
-      let state = new State();
+      const state = new State();
       state.on('fetch_with_changes', function (keys) {
         expect(keys).to.eql(['foo']);
         done();
@@ -101,7 +101,7 @@ describe('State Management', function () {
     });
 
     it('should have events that attach to scope', function (done) {
-      let state = new State();
+      const state = new State();
       state.on('test', function (message) {
         expect(message).to.equal('foo');
         done();
@@ -111,7 +111,7 @@ describe('State Management', function () {
     });
 
     it('should fire listeners for #onUpdate() on #fetch()', function (done) {
-      let state = new State();
+      const state = new State();
       state.on('fetch_with_changes', function (keys) {
         expect(keys).to.eql(['foo']);
         done();
@@ -123,7 +123,7 @@ describe('State Management', function () {
     });
 
     it('should apply defaults to fetches', function () {
-      let state = new State('_s', { message: 'test' });
+      const state = new State('_s', { message: 'test' });
       $location.search({ _s: '(foo:bar)' });
       state.fetch();
       expect(state).to.have.property('foo', 'bar');
@@ -131,15 +131,15 @@ describe('State Management', function () {
     });
 
     it('should call fetch when $routeUpdate is fired on $rootScope', function () {
-      let state = new State();
-      let spy = sinon.spy(state, 'fetch');
+      const state = new State();
+      const spy = sinon.spy(state, 'fetch');
       $rootScope.$emit('$routeUpdate', 'test');
       sinon.assert.calledOnce(spy);
     });
 
     it('should clear state when missing form URL', function () {
       let stateObj;
-      let state = new State();
+      const state = new State();
 
       // set satte via URL
       $location.search({ _s: '(foo:(bar:baz))' });
diff --git a/src/ui/public/state_management/app_state.js b/src/ui/public/state_management/app_state.js
index c2312c5cdcffa..a77b267cafce2 100644
--- a/src/ui/public/state_management/app_state.js
+++ b/src/ui/public/state_management/app_state.js
@@ -2,11 +2,11 @@ import _ from 'lodash';
 import modules from 'ui/modules';
 import StateManagementStateProvider from 'ui/state_management/state';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
-let urlParam = '_a';
+const urlParam = '_a';
 
 function AppStateProvider(Private, $rootScope, $location) {
-  let State = Private(StateManagementStateProvider);
-  let PersistedState = Private(PersistedStatePersistedStateProvider);
+  const State = Private(StateManagementStateProvider);
+  const PersistedState = Private(PersistedStatePersistedStateProvider);
   let persistedStates;
   let eventUnsubscribers;
 
@@ -30,31 +30,31 @@ function AppStateProvider(Private, $rootScope, $location) {
 
   AppState.prototype.makeStateful = function (prop) {
     if (persistedStates[prop]) return persistedStates[prop];
-    let self = this;
+    const self = this;
 
     // set up the ui state
     persistedStates[prop] = new PersistedState();
 
     // update the app state when the stateful instance changes
-    let updateOnChange = function () {
-      let replaceState = false; // TODO: debouncing logic
+    const updateOnChange = function () {
+      const replaceState = false; // TODO: debouncing logic
 
       self[prop] = persistedStates[prop].getChanges();
       self.save(replaceState);
     };
-    let handlerOnChange = (method) => persistedStates[prop][method]('change', updateOnChange);
+    const handlerOnChange = (method) => persistedStates[prop][method]('change', updateOnChange);
     handlerOnChange('on');
     eventUnsubscribers.push(() => handlerOnChange('off'));
 
     // update the stateful object when the app state changes
-    let persistOnChange = function (changes) {
+    const persistOnChange = function (changes) {
       if (!changes) return;
 
       if (changes.indexOf(prop) !== -1) {
         persistedStates[prop].set(self[prop]);
       }
     };
-    let handlePersist = (method) => this[method]('fetch_with_changes', persistOnChange);
+    const handlePersist = (method) => this[method]('fetch_with_changes', persistOnChange);
     handlePersist('on');
     eventUnsubscribers.push(() => handlePersist('off'));
 
@@ -73,7 +73,7 @@ function AppStateProvider(Private, $rootScope, $location) {
 
     // Checks to see if the appState might already exist, even if it hasn't been newed up
     get.previouslyStored = function () {
-      let search = $location.search();
+      const search = $location.search();
       return search[urlParam] ? true : false;
     };
 
diff --git a/src/ui/public/state_management/global_state.js b/src/ui/public/state_management/global_state.js
index 7448822d7b8b8..81c875b086a6f 100644
--- a/src/ui/public/state_management/global_state.js
+++ b/src/ui/public/state_management/global_state.js
@@ -5,10 +5,10 @@ import rison from 'rison-node';
 import StateManagementStateProvider from 'ui/state_management/state';
 import uiModules from 'ui/modules';
 
-let module = uiModules.get('kibana/global_state');
+const module = uiModules.get('kibana/global_state');
 
 function GlobalStateProvider(Private, $rootScope, $location) {
-  let State = Private(StateManagementStateProvider);
+  const State = Private(StateManagementStateProvider);
 
   _.class(GlobalState).inherits(State);
   function GlobalState(defaults) {
diff --git a/src/ui/public/state_management/state.js b/src/ui/public/state_management/state.js
index 7b934567e01ff..e86b88d360f5a 100644
--- a/src/ui/public/state_management/state.js
+++ b/src/ui/public/state_management/state.js
@@ -14,7 +14,7 @@ export default function StateProvider(Private, $rootScope, $location) {
   function State(urlParam, defaults) {
     State.Super.call(this);
 
-    let self = this;
+    const self = this;
     self.setDefaults(defaults);
     self._urlParam = urlParam || '_s';
 
@@ -45,7 +45,7 @@ export default function StateProvider(Private, $rootScope, $location) {
   }
 
   State.prototype._readFromURL = function () {
-    let search = $location.search();
+    const search = $location.search();
     try {
       return search[this._urlParam] ? rison.decode(search[this._urlParam]) : null;
     } catch (e) {
@@ -74,7 +74,7 @@ export default function StateProvider(Private, $rootScope, $location) {
 
     _.defaults(stash, this._defaults);
     // apply diff to state from stash, will change state in place via side effect
-    let diffResults = applyDiff(this, stash);
+    const diffResults = applyDiff(this, stash);
 
     if (diffResults.keys.length) {
       this.emit('fetch_with_changes', diffResults.keys);
@@ -87,7 +87,7 @@ export default function StateProvider(Private, $rootScope, $location) {
    */
   State.prototype.save = function (replace) {
     let stash = this._readFromURL();
-    let state = this.toObject();
+    const state = this.toObject();
     replace = replace || false;
 
     if (!stash) {
@@ -97,14 +97,14 @@ export default function StateProvider(Private, $rootScope, $location) {
 
     _.defaults(state, this._defaults);
     // apply diff to state from stash, will change state in place via side effect
-    let diffResults = applyDiff(stash, state);
+    const diffResults = applyDiff(stash, state);
 
     if (diffResults.keys.length) {
       this.emit('save_with_changes', diffResults.keys);
     }
 
     // persist the state in the URL
-    let search = $location.search();
+    const search = $location.search();
     search[this._urlParam] = this.toRISON();
     if (replace) {
       $location.search(search).replace();
@@ -129,7 +129,7 @@ export default function StateProvider(Private, $rootScope, $location) {
   State.prototype.reset = function () {
     // apply diff to _attributes from defaults, this is side effecting so
     // it will change the state in place.
-    let diffResults = applyDiff(this, this._defaults);
+    const diffResults = applyDiff(this, this._defaults);
     if (diffResults.keys.length) {
       this.emit('reset_with_changes', diffResults.keys);
     }
diff --git a/src/ui/public/storage/__tests__/storage.js b/src/ui/public/storage/__tests__/storage.js
index 8a4d5e2872f7c..f5f5f7a7c425c 100644
--- a/src/ui/public/storage/__tests__/storage.js
+++ b/src/ui/public/storage/__tests__/storage.js
@@ -5,7 +5,7 @@ import 'ui/storage';
 
 let storage;
 let $window;
-let payload = { first: 'john', last: 'smith' };
+const payload = { first: 'john', last: 'smith' };
 
 
 function init() {
@@ -69,21 +69,21 @@ describe('StorageService', function () {
 
   describe('json data', function () {
     it('should parse JSON when reading from the store', function () {
-      let getItem = $window.localStorage.getItem;
+      const getItem = $window.localStorage.getItem;
       getItem.returns(JSON.stringify(payload));
 
-      let data = storage.get('name');
+      const data = storage.get('name');
       expect(data).to.eql(payload);
     });
 
     it('should write JSON string to the store', function () {
-      let setItem = $window.localStorage.setItem;
-      let key = 'name';
-      let value = payload;
+      const setItem = $window.localStorage.setItem;
+      const key = 'name';
+      const value = payload;
 
       storage.set(key, value);
 
-      let call = setItem.getCall(0);
+      const call = setItem.getCall(0);
       expect(call.args[0]).to.equal(key);
       expect(call.args[1]).to.equal(JSON.stringify(value));
     });
@@ -91,15 +91,15 @@ describe('StorageService', function () {
 
   describe('expected responses', function () {
     it('should return null when not exists', function () {
-      let data = storage.get('notexists');
+      const data = storage.get('notexists');
       expect(data).to.equal(null);
     });
 
     it('should return null when invalid JSON', function () {
-      let getItem = $window.localStorage.getItem;
+      const getItem = $window.localStorage.getItem;
       getItem.returns('not: json');
 
-      let data = storage.get('name');
+      const data = storage.get('name');
       expect(data).to.equal(null);
     });
   });
diff --git a/src/ui/public/storage/storage.js b/src/ui/public/storage/storage.js
index aa043158724bd..eaa243ed5be1d 100644
--- a/src/ui/public/storage/storage.js
+++ b/src/ui/public/storage/storage.js
@@ -2,7 +2,7 @@ import modules from 'ui/modules';
 import angular from 'angular';
 
 function Storage(store) {
-  let self = this;
+  const self = this;
   self.store = store;
 
   self.get = function (key) {
@@ -30,7 +30,7 @@ function Storage(store) {
   };
 }
 
-let createService = function (type) {
+const createService = function (type) {
   return function ($window) {
     return new Storage($window[type]);
   };
diff --git a/src/ui/public/stringify/__tests__/_color.js b/src/ui/public/stringify/__tests__/_color.js
index f48823ea3d5e1..4d3a73eb7b251 100644
--- a/src/ui/public/stringify/__tests__/_color.js
+++ b/src/ui/public/stringify/__tests__/_color.js
@@ -13,7 +13,7 @@ describe('Color Format', function () {
   }));
 
   it('should add colors if the value is in range', function () {
-    let colorer = new ColorFormat({
+    const colorer = new ColorFormat({
       colors: [{
         range: '100:150',
         text: 'blue',
@@ -27,7 +27,7 @@ describe('Color Format', function () {
   });
 
   it('should not convert invalid ranges', function () {
-    let colorer = new ColorFormat({
+    const colorer = new ColorFormat({
       colors: [{
         range: '100150',
         text: 'blue',
diff --git a/src/ui/public/stringify/__tests__/_date.js b/src/ui/public/stringify/__tests__/_date.js
index aec730580bf48..c3a90a2c1d7f1 100644
--- a/src/ui/public/stringify/__tests__/_date.js
+++ b/src/ui/public/stringify/__tests__/_date.js
@@ -15,8 +15,8 @@ describe('Date Format', function () {
     settings = config;
 
     fieldFormats = Private(RegistryFieldFormatsProvider);
-    let DateFormat = fieldFormats.getType('date');
-    let date = new DateFormat();
+    const DateFormat = fieldFormats.getType('date');
+    const date = new DateFormat();
 
     convert = date.convert.bind(date);
   }));
@@ -30,17 +30,17 @@ describe('Date Format', function () {
     function setDefaultTimezone() {
       moment.tz.setDefault(settings.get('dateFormat:tz'));
     }
-    let time = 1445027693942;
+    const time = 1445027693942;
 
     off = $scope.$on('change:config.dateFormat:tz', setDefaultTimezone);
 
     settings.set('dateFormat:tz', 'America/Chicago');
     $scope.$digest();
-    let chicagoTime = convert(time);
+    const chicagoTime = convert(time);
 
     settings.set('dateFormat:tz', 'America/Phoenix');
     $scope.$digest();
-    let phoenixTime = convert(time);
+    const phoenixTime = convert(time);
 
     expect(chicagoTime).not.to.equal(phoenixTime);
     off();
diff --git a/src/ui/public/stringify/__tests__/_source.js b/src/ui/public/stringify/__tests__/_source.js
index 63d4691c33b09..38806c03dbed0 100644
--- a/src/ui/public/stringify/__tests__/_source.js
+++ b/src/ui/public/stringify/__tests__/_source.js
@@ -28,8 +28,8 @@ describe('_source formatting', function () {
     }));
 
     it('uses the _source, field, and hit to create a <dl>', function () {
-      let hit = _.first(hits);
-      let $dl = $(convertHtml(hit._source, indexPattern.fields.byName._source, hit));
+      const hit = _.first(hits);
+      const $dl = $(convertHtml(hit._source, indexPattern.fields.byName._source, hit));
       expect($dl.is('dl')).to.be.ok();
       expect($dl.find('dt')).to.have.length(_.keys(indexPattern.flattenHit(hit)).length);
     });
diff --git a/src/ui/public/stringify/__tests__/_string.js b/src/ui/public/stringify/__tests__/_string.js
index f0b4b254db15e..19212e23b6670 100644
--- a/src/ui/public/stringify/__tests__/_string.js
+++ b/src/ui/public/stringify/__tests__/_string.js
@@ -10,16 +10,16 @@ describe('String Format', function () {
   }));
 
   it('decode a base64 string', function () {
-    let StringFormat = fieldFormats.getType('string');
-    let string = new StringFormat({
+    const StringFormat = fieldFormats.getType('string');
+    const string = new StringFormat({
       transform: 'base64'
     });
     expect(string.convert('Zm9vYmFy')).to.be('foobar');
   });
 
   it('convert a string to title case', function () {
-    let StringFormat = fieldFormats.getType('string');
-    let string = new StringFormat({
+    const StringFormat = fieldFormats.getType('string');
+    const string = new StringFormat({
       transform: 'title'
     });
     expect(string.convert('PLEASE DO NOT SHOUT')).to.be('Please Do Not Shout');
diff --git a/src/ui/public/stringify/__tests__/_truncate.js b/src/ui/public/stringify/__tests__/_truncate.js
index 7e9564944402a..7f36690b8e1c7 100644
--- a/src/ui/public/stringify/__tests__/_truncate.js
+++ b/src/ui/public/stringify/__tests__/_truncate.js
@@ -10,29 +10,29 @@ describe('String Truncate Format', function () {
   }));
 
   it('truncate large string', function () {
-    let Truncate = fieldFormats.getType('truncate');
-    let truncate = new Truncate({fieldLength: 4});
+    const Truncate = fieldFormats.getType('truncate');
+    const truncate = new Truncate({fieldLength: 4});
 
     expect(truncate.convert('This is some text')).to.be('This...');
   });
 
   it('does not truncate large string when field length is not a string', function () {
-    let Truncate = fieldFormats.getType('truncate');
-    let truncate = new Truncate({fieldLength: 'not number'});
+    const Truncate = fieldFormats.getType('truncate');
+    const truncate = new Truncate({fieldLength: 'not number'});
 
     expect(truncate.convert('This is some text')).to.be('This is some text');
   });
 
   it('does not truncate large string when field length is null', function () {
-    let Truncate = fieldFormats.getType('truncate');
-    let truncate = new Truncate({fieldLength: null});
+    const Truncate = fieldFormats.getType('truncate');
+    const truncate = new Truncate({fieldLength: null});
 
     expect(truncate.convert('This is some text')).to.be('This is some text');
   });
 
   it('does not truncate large string when field length larger than the text', function () {
-    let Truncate = fieldFormats.getType('truncate');
-    let truncate = new Truncate({fieldLength: 100000});
+    const Truncate = fieldFormats.getType('truncate');
+    const truncate = new Truncate({fieldLength: 100000});
 
     expect(truncate.convert('This is some text')).to.be('This is some text');
   });
diff --git a/src/ui/public/stringify/__tests__/_url.js b/src/ui/public/stringify/__tests__/_url.js
index 845ad0fb27885..48a918e67b867 100644
--- a/src/ui/public/stringify/__tests__/_url.js
+++ b/src/ui/public/stringify/__tests__/_url.js
@@ -19,9 +19,9 @@ describe('Url Format', function () {
     });
 
     it('ouputs a simple <a> tab by default', function () {
-      let url = new Url();
+      const url = new Url();
 
-      let $a = $(url.convert('http://elastic.co', 'html'));
+      const $a = $(url.convert('http://elastic.co', 'html'));
       expect($a.is('a')).to.be(true);
       expect($a.size()).to.be(1);
       expect($a.attr('href')).to.be('http://elastic.co');
@@ -30,17 +30,17 @@ describe('Url Format', function () {
     });
 
     it('outputs an <image> if type === "img"', function () {
-      let url = new Url({ type: 'img' });
+      const url = new Url({ type: 'img' });
 
-      let $img = $(url.convert('http://elastic.co', 'html'));
+      const $img = $(url.convert('http://elastic.co', 'html'));
       expect($img.is('img')).to.be(true);
       expect($img.attr('src')).to.be('http://elastic.co');
     });
 
     describe('url template', function () {
       it('accepts a template', function () {
-        let url = new Url({ urlTemplate: 'url: {{ value }}' });
-        let $a = $(url.convert('url', 'html'));
+        const url = new Url({ urlTemplate: 'url: {{ value }}' });
+        const $a = $(url.convert('url', 'html'));
         expect($a.is('a')).to.be(true);
         expect($a.size()).to.be(1);
         expect($a.attr('href')).to.be('url: url');
@@ -49,15 +49,15 @@ describe('Url Format', function () {
       });
 
       it('only outputs the url if the contentType === "text"', function () {
-        let url = new Url();
+        const url = new Url();
         expect(url.convert('url', 'text')).to.be('url');
       });
     });
 
     describe('label template', function () {
       it('accepts a template', function () {
-        let url = new Url({ labelTemplate: 'extension: {{ value }}' });
-        let $a = $(url.convert('php', 'html'));
+        const url = new Url({ labelTemplate: 'extension: {{ value }}' });
+        const $a = $(url.convert('php', 'html'));
         expect($a.is('a')).to.be(true);
         expect($a.size()).to.be(1);
         expect($a.attr('href')).to.be('php');
@@ -65,19 +65,19 @@ describe('Url Format', function () {
       });
 
       it('uses the label template for text formating', function () {
-        let url = new Url({ labelTemplate: 'external {{value }}'});
+        const url = new Url({ labelTemplate: 'external {{value }}'});
         expect(url.convert('url', 'text')).to.be('external url');
       });
 
       it('can use the raw value', function () {
-        let url = new Url({
+        const url = new Url({
           labelTemplate: 'external {{value}}'
         });
         expect(url.convert('url?', 'text')).to.be('external url?');
       });
 
       it('can use the url', function () {
-        let url = new Url({
+        const url = new Url({
           urlTemplate: 'http://google.com/{{value}}',
           labelTemplate: 'external {{url}}'
         });
@@ -87,19 +87,19 @@ describe('Url Format', function () {
 
     describe('templating', function () {
       it('ignores unknown variables', function () {
-        let url = new Url({ urlTemplate: '{{ not really a var }}' });
+        const url = new Url({ urlTemplate: '{{ not really a var }}' });
         expect(url.convert('url', 'text')).to.be('');
       });
 
       it('does not allow executing code in variable expressions', function () {
         window.SHOULD_NOT_BE_TRUE = false;
-        let url = new Url({ urlTemplate: '{{ (window.SHOULD_NOT_BE_TRUE = true) && value }}' });
+        const url = new Url({ urlTemplate: '{{ (window.SHOULD_NOT_BE_TRUE = true) && value }}' });
         expect(url.convert('url', 'text')).to.be('');
       });
 
       describe('', function () {
         it('does not get values from the prototype chain', function () {
-          let url = new Url({ urlTemplate: '{{ toString }}' });
+          const url = new Url({ urlTemplate: '{{ toString }}' });
           expect(url.convert('url', 'text')).to.be('');
         });
       });
diff --git a/src/ui/public/stringify/types/_numeral.js b/src/ui/public/stringify/types/_numeral.js
index ee55f155b4341..9bbab9715436e 100644
--- a/src/ui/public/stringify/types/_numeral.js
+++ b/src/ui/public/stringify/types/_numeral.js
@@ -3,9 +3,9 @@ import 'ui/field_format_editor/numeral/numeral';
 import IndexPatternsFieldFormatProvider from 'ui/index_patterns/_field_format/field_format';
 import BoundToConfigObjProvider from 'ui/bound_to_config_obj';
 export default function AbstractNumeralFormatProvider(Private) {
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
-  let BoundToConfigObj = Private(BoundToConfigObjProvider);
-  let numeral = require('numeral')();
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const BoundToConfigObj = Private(BoundToConfigObjProvider);
+  const numeral = require('numeral')();
 
   _.class(Numeral).inherits(FieldFormat);
   function Numeral(params) {
diff --git a/src/ui/public/stringify/types/boolean.js b/src/ui/public/stringify/types/boolean.js
index 651b129ad0783..6c522db02527c 100644
--- a/src/ui/public/stringify/types/boolean.js
+++ b/src/ui/public/stringify/types/boolean.js
@@ -3,7 +3,7 @@ import _ from 'lodash';
 
 export default function TruncateFormatProvider(Private) {
 
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
 
   class Bool extends FieldFormat {
 
diff --git a/src/ui/public/stringify/types/bytes.js b/src/ui/public/stringify/types/bytes.js
index 88e72823a4a4c..a585656df150b 100644
--- a/src/ui/public/stringify/types/bytes.js
+++ b/src/ui/public/stringify/types/bytes.js
@@ -1,7 +1,7 @@
 import StringifyTypesNumeralProvider from 'ui/stringify/types/_numeral';
 
 export default function BytesFormatProvider(Private) {
-  let Numeral = Private(StringifyTypesNumeralProvider);
+  const Numeral = Private(StringifyTypesNumeralProvider);
   return Numeral.factory({
     id: 'bytes',
     title: 'Bytes',
diff --git a/src/ui/public/stringify/types/date.js b/src/ui/public/stringify/types/date.js
index d88ff3ed4d910..b0faef57501a0 100644
--- a/src/ui/public/stringify/types/date.js
+++ b/src/ui/public/stringify/types/date.js
@@ -5,8 +5,8 @@ import IndexPatternsFieldFormatProvider from 'ui/index_patterns/_field_format/fi
 import BoundToConfigObjProvider from 'ui/bound_to_config_obj';
 import dateTemplate from 'ui/stringify/editors/date.html';
 export default function DateTimeFormatProvider(Private) {
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
-  let BoundToConfigObj = Private(BoundToConfigObjProvider);
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const BoundToConfigObj = Private(BoundToConfigObjProvider);
 
 
   _.class(DateTime).inherits(FieldFormat);
@@ -27,7 +27,7 @@ export default function DateTimeFormatProvider(Private) {
     template: dateTemplate,
     controllerAs: 'cntrl',
     controller: function ($interval, $scope) {
-      let self = this;
+      const self = this;
       self.sampleInputs = [
         Date.now(),
         +moment().startOf('year'),
@@ -43,11 +43,11 @@ export default function DateTimeFormatProvider(Private) {
   DateTime.prototype._convert = function (val) {
     // don't give away our ref to converter so
     // we can hot-swap when config changes
-    let pattern = this.param('pattern');
-    let timezone = this.param('timezone');
+    const pattern = this.param('pattern');
+    const timezone = this.param('timezone');
 
-    let timezoneChanged = this._timeZone !== timezone;
-    let datePatternChanged = this._memoizedPattern !== pattern;
+    const timezoneChanged = this._timeZone !== timezone;
+    const datePatternChanged = this._memoizedPattern !== pattern;
     if (timezoneChanged || datePatternChanged) {
       this._timeZone = timezone;
       this._memoizedPattern = pattern;
diff --git a/src/ui/public/stringify/types/ip.js b/src/ui/public/stringify/types/ip.js
index 465d77fc3b41e..875c20401afc5 100644
--- a/src/ui/public/stringify/types/ip.js
+++ b/src/ui/public/stringify/types/ip.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import IndexPatternsFieldFormatProvider from 'ui/index_patterns/_field_format/field_format';
 export default function IpFormatProvider(Private) {
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
 
   _.class(Ip).inherits(FieldFormat);
   function Ip(params) {
diff --git a/src/ui/public/stringify/types/number.js b/src/ui/public/stringify/types/number.js
index e9d12b1d241f2..569be5cf32bc4 100644
--- a/src/ui/public/stringify/types/number.js
+++ b/src/ui/public/stringify/types/number.js
@@ -1,7 +1,7 @@
 import StringifyTypesNumeralProvider from 'ui/stringify/types/_numeral';
 
 export default function NumberFormatProvider(Private) {
-  let Numeral = Private(StringifyTypesNumeralProvider);
+  const Numeral = Private(StringifyTypesNumeralProvider);
   return Numeral.factory({
     id: 'number',
     title: 'Number',
diff --git a/src/ui/public/stringify/types/percent.js b/src/ui/public/stringify/types/percent.js
index f309604ef0f0b..d4a2d672a0829 100644
--- a/src/ui/public/stringify/types/percent.js
+++ b/src/ui/public/stringify/types/percent.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 import BoundToConfigObjProvider from 'ui/bound_to_config_obj';
 import StringifyTypesNumeralProvider from 'ui/stringify/types/_numeral';
 export default function PercentFormatProvider(Private) {
-  let BoundToConfigObj = Private(BoundToConfigObjProvider);
-  let Numeral = Private(StringifyTypesNumeralProvider);
+  const BoundToConfigObj = Private(BoundToConfigObjProvider);
+  const Numeral = Private(StringifyTypesNumeralProvider);
 
   return Numeral.factory({
     id: 'percent',
diff --git a/src/ui/public/stringify/types/source.js b/src/ui/public/stringify/types/source.js
index 9662bfebef4ec..55fcde64cb491 100644
--- a/src/ui/public/stringify/types/source.js
+++ b/src/ui/public/stringify/types/source.js
@@ -3,8 +3,8 @@ import noWhiteSpace from 'ui/utils/no_white_space';
 import angular from 'angular';
 import IndexPatternsFieldFormatProvider from 'ui/index_patterns/_field_format/field_format';
 export default function _SourceFormatProvider(Private, shortDotsFilter) {
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
-  let template = _.template(noWhiteSpace(require('ui/stringify/types/_source.html')));
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const template = _.template(noWhiteSpace(require('ui/stringify/types/_source.html')));
 
   _.class(Source).inherits(FieldFormat);
   function Source(params) {
@@ -20,15 +20,15 @@ export default function _SourceFormatProvider(Private, shortDotsFilter) {
     html: function sourceToHtml(source, field, hit) {
       if (!field) return this.getConverter('text')(source, field, hit);
 
-      let highlights = (hit && hit.highlight) || {};
-      let formatted = field.indexPattern.formatHit(hit);
-      let highlightPairs = [];
-      let sourcePairs = [];
+      const highlights = (hit && hit.highlight) || {};
+      const formatted = field.indexPattern.formatHit(hit);
+      const highlightPairs = [];
+      const sourcePairs = [];
 
       _.keys(formatted).forEach(function (key) {
-        let pairs = highlights[key] ? highlightPairs : sourcePairs;
-        let field = shortDotsFilter(key);
-        let val = formatted[key];
+        const pairs = highlights[key] ? highlightPairs : sourcePairs;
+        const field = shortDotsFilter(key);
+        const val = formatted[key];
         pairs.push([field, val]);
       }, []);
 
diff --git a/src/ui/public/stringify/types/string.js b/src/ui/public/stringify/types/string.js
index 3db37865534e7..259469706ab68 100644
--- a/src/ui/public/stringify/types/string.js
+++ b/src/ui/public/stringify/types/string.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import 'ui/field_format_editor/samples/samples';
 import IndexPatternsFieldFormatProvider from 'ui/index_patterns/_field_format/field_format';
 export default function StringFormatProvider(Private) {
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
 
 
   _.class(_String).inherits(FieldFormat);
diff --git a/src/ui/public/stringify/types/truncate.js b/src/ui/public/stringify/types/truncate.js
index 666add8819581..b20a7c2c62092 100644
--- a/src/ui/public/stringify/types/truncate.js
+++ b/src/ui/public/stringify/types/truncate.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 
 import IndexPatternsFieldFormatProvider from 'ui/index_patterns/_field_format/field_format';
 export default function TruncateFormatProvider(Private) {
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
-  let omission = '...';
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const omission = '...';
 
   _.class(Truncate).inherits(FieldFormat);
 
@@ -16,7 +16,7 @@ export default function TruncateFormatProvider(Private) {
   Truncate.fieldType = ['string'];
 
   Truncate.prototype._convert = function (val) {
-    let length = this.param('fieldLength');
+    const length = this.param('fieldLength');
     if (length > 0) {
       return _.trunc(val, {
         'length': length + omission.length,
diff --git a/src/ui/public/stringify/types/url.js b/src/ui/public/stringify/types/url.js
index eb1c46aeaaafe..a848567523ed9 100644
--- a/src/ui/public/stringify/types/url.js
+++ b/src/ui/public/stringify/types/url.js
@@ -5,7 +5,7 @@ import IndexPatternsFieldFormatProvider from 'ui/index_patterns/_field_format/fi
 import urlTemplate from 'ui/stringify/editors/url.html';
 export default function UrlFormatProvider(Private, highlightFilter) {
 
-  let FieldFormat = Private(IndexPatternsFieldFormatProvider);
+  const FieldFormat = Private(IndexPatternsFieldFormatProvider);
 
 
   _.class(Url).inherits(FieldFormat);
@@ -31,7 +31,7 @@ export default function UrlFormatProvider(Private, highlightFilter) {
     template: urlTemplate,
     controllerAs: 'url',
     controller: function ($scope) {
-      let iconPattern = '/bundles/src/ui/public/stringify/icons/{{value}}.png';
+      const iconPattern = '/bundles/src/ui/public/stringify/icons/{{value}}.png';
 
       this.samples = {
         a: [ 'john', '/some/pathname/asset.png', 1234 ],
@@ -39,7 +39,7 @@ export default function UrlFormatProvider(Private, highlightFilter) {
       };
 
       $scope.$watch('editor.formatParams.type', function (type, prev) {
-        let params = $scope.editor.formatParams;
+        const params = $scope.editor.formatParams;
         if (type === 'img' && type !== prev && !params.urlTemplate) {
           params.urlTemplate = iconPattern;
         }
@@ -60,7 +60,7 @@ export default function UrlFormatProvider(Private, highlightFilter) {
   ];
 
   Url.prototype._formatUrl = function (value) {
-    let template = this.param('urlTemplate');
+    const template = this.param('urlTemplate');
     if (!template) return value;
 
     return this._compileTemplate(template)({
@@ -70,7 +70,7 @@ export default function UrlFormatProvider(Private, highlightFilter) {
   };
 
   Url.prototype._formatLabel = function (value, url) {
-    let template = this.param('labelTemplate');
+    const template = this.param('labelTemplate');
     if (url == null) url = this._formatUrl(value);
     if (!template) return url;
 
@@ -86,7 +86,7 @@ export default function UrlFormatProvider(Private, highlightFilter) {
     },
 
     html: function (rawValue, field, hit) {
-      let url = _.escape(this._formatUrl(rawValue));
+      const url = _.escape(this._formatUrl(rawValue));
       let label = _.escape(this._formatLabel(rawValue, url));
 
       switch (this.param('type')) {
@@ -103,7 +103,7 @@ export default function UrlFormatProvider(Private, highlightFilter) {
   };
 
   Url.prototype._compileTemplate = function (template) {
-    let parts = template.split(Url.templateMatchRE).map(function (part, i) {
+    const parts = template.split(Url.templateMatchRE).map(function (part, i) {
       // trim all the odd bits, the variable names
       return (i % 2) ? part.trim() : part;
     });
@@ -115,7 +115,7 @@ export default function UrlFormatProvider(Private, highlightFilter) {
       while (++i < parts.length) {
         if (i % 2) {
           if (locals.hasOwnProperty(parts[i])) {
-            let local = locals[parts[i]];
+            const local = locals[parts[i]];
             output += local == null ? '' : local;
           }
         } else {
diff --git a/src/ui/public/style_compile/__tests__/style_compile.js b/src/ui/public/style_compile/__tests__/style_compile.js
index 3bb46d7f3cb27..804e0f0b59287 100644
--- a/src/ui/public/style_compile/__tests__/style_compile.js
+++ b/src/ui/public/style_compile/__tests__/style_compile.js
@@ -13,7 +13,7 @@ describe('styleCompile directive', function () {
   }));
 
   it('exports a few config values as css', function () {
-    let $style = $('#style-compile');
+    const $style = $('#style-compile');
 
     config.set('truncate:maxHeight', 0);
     $rootScope.$apply();
diff --git a/src/ui/public/style_compile/style_compile.js b/src/ui/public/style_compile/style_compile.js
index 4ec2bd7367c03..90fc2e09fecbd 100644
--- a/src/ui/public/style_compile/style_compile.js
+++ b/src/ui/public/style_compile/style_compile.js
@@ -2,15 +2,15 @@ import _ from 'lodash';
 import $ from 'jquery';
 import 'ui/config';
 import uiModules from 'ui/modules';
-let $style = $('<style>').appendTo('head').attr('id', 'style-compile');
+const $style = $('<style>').appendTo('head').attr('id', 'style-compile');
 
 
 uiModules
 .get('kibana')
 .run(function ($rootScope, $compile, config) {
-  let truncateGradientHeight = 15;
-  let template = _.template(require('./style_compile.css.tmpl'));
-  let locals = {};
+  const truncateGradientHeight = 15;
+  const template = _.template(require('./style_compile.css.tmpl'));
+  const locals = {};
 
   // watch the value of the truncate:maxHeight config param
   $rootScope.$watch(function () {
diff --git a/src/ui/public/template_vis_type/template_renderbot.js b/src/ui/public/template_vis_type/template_renderbot.js
index 1dfcfd31f8ae2..8a9d26b71e1bf 100644
--- a/src/ui/public/template_vis_type/template_renderbot.js
+++ b/src/ui/public/template_vis_type/template_renderbot.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import VisRenderbotProvider from 'ui/vis/renderbot';
 export default function TemplateRenderbotFactory(Private, $compile, $rootScope) {
-  let Renderbot = Private(VisRenderbotProvider);
+  const Renderbot = Private(VisRenderbotProvider);
 
   _.class(TemplateRenderbot).inherits(Renderbot);
   function TemplateRenderbot(vis, $el, uiState) {
diff --git a/src/ui/public/template_vis_type/template_vis_type.js b/src/ui/public/template_vis_type/template_vis_type.js
index 3203b047ac583..0ed97150e8085 100644
--- a/src/ui/public/template_vis_type/template_vis_type.js
+++ b/src/ui/public/template_vis_type/template_vis_type.js
@@ -2,8 +2,8 @@ import _ from 'lodash';
 import VisVisTypeProvider from 'ui/vis/vis_type';
 import TemplateVisTypeTemplateRenderbotProvider from 'ui/template_vis_type/template_renderbot';
 export default function TemplateVisTypeFactory(Private) {
-  let VisType = Private(VisVisTypeProvider);
-  let TemplateRenderbot = Private(TemplateVisTypeTemplateRenderbotProvider);
+  const VisType = Private(VisVisTypeProvider);
+  const TemplateRenderbot = Private(TemplateVisTypeTemplateRenderbotProvider);
 
   _.class(TemplateVisType).inherits(VisType);
   function TemplateVisType(opts) {
diff --git a/src/ui/public/test_harness/test_harness.js b/src/ui/public/test_harness/test_harness.js
index 9b68ffea17a13..fd9e262a7d3eb 100644
--- a/src/ui/public/test_harness/test_harness.js
+++ b/src/ui/public/test_harness/test_harness.js
@@ -18,8 +18,8 @@ $('body').attr('id', 'test-harness-body'); // so we can make high priority selec
 
 
 /*** Setup seeded random ***/
-let seedInput = parse(window.location.href, true).query.seed;
-let seed = _.add(seedInput, 0) || Date.now();
+const seedInput = parse(window.location.href, true).query.seed;
+const seed = _.add(seedInput, 0) || Date.now();
 Math.random = _.bindKey(new Nonsense(seed), 'frac');
 Math.random.nonsense = new Nonsense(seed);
 console.log('Random-ness seed: ' + seed);
@@ -38,7 +38,7 @@ before(function () {
   this.timeout(30000);
 
   let mapper;
-  let Runner = window.Mocha.Runner;
+  const Runner = window.Mocha.Runner;
 
   Runner.prototype.emit = _.wrap(Runner.prototype.emit, function (emit, event, test, err) {
     if (err && mapper) err = mapper.mapError(err);
diff --git a/src/ui/public/time_buckets/calc_auto_interval.js b/src/ui/public/time_buckets/calc_auto_interval.js
index 4c0889ffe16c9..ee2955ef1f9f9 100644
--- a/src/ui/public/time_buckets/calc_auto_interval.js
+++ b/src/ui/public/time_buckets/calc_auto_interval.js
@@ -3,7 +3,7 @@ import moment from 'moment';
 export default function DateIntervalRoundingRulesProvider() {
   // these are the rounding rules used by roundInterval()
 
-  let roundingRules = [
+  const roundingRules = [
     [ d(500, 'ms'), d(100, 'ms') ],
     [ d(5, 'second'), d(1, 'second') ],
     [ d(7.5, 'second'), d(5, 'second') ],
@@ -22,16 +22,16 @@ export default function DateIntervalRoundingRulesProvider() {
     [ Infinity, d(1, 'year') ]
   ];
 
-  let revRoundingRules = roundingRules.slice(0).reverse();
+  const revRoundingRules = roundingRules.slice(0).reverse();
 
   function find(rules, check, last) {
     function pick(buckets, duration) {
-      let target = duration / buckets;
+      const target = duration / buckets;
       let lastResp;
 
       for (let i = 0; i < rules.length; i++) {
-        let rule = rules[i];
-        let resp = check(rule[0], rule[1], target);
+        const rule = rules[i];
+        const resp = check(rule[0], rule[1], target);
 
         if (resp == null) {
           if (!last) continue;
@@ -44,12 +44,12 @@ export default function DateIntervalRoundingRulesProvider() {
       }
 
       // fallback to just a number of milliseconds, ensure ms is >= 1
-      let ms = Math.max(Math.floor(target), 1);
+      const ms = Math.max(Math.floor(target), 1);
       return moment.duration(ms, 'ms');
     }
 
     return function (buckets, duration) {
-      let interval = pick(buckets, duration);
+      const interval = pick(buckets, duration);
       if (interval) return moment.duration(interval._data);
     };
   }
diff --git a/src/ui/public/time_buckets/calc_es_interval.js b/src/ui/public/time_buckets/calc_es_interval.js
index 9723273b372af..f158190792042 100644
--- a/src/ui/public/time_buckets/calc_es_interval.js
+++ b/src/ui/public/time_buckets/calc_es_interval.js
@@ -2,8 +2,8 @@ import moment from 'moment';
 import dateMath from '@elastic/datemath';
 export default function () {
 
-  let unitsDesc = dateMath.unitsDesc;
-  let largeMax = unitsDesc.indexOf('M');
+  const unitsDesc = dateMath.unitsDesc;
+  const largeMax = unitsDesc.indexOf('M');
 
   /**
    * Convert a moment.duration into an es
@@ -15,8 +15,8 @@ export default function () {
    */
   function esDuration(duration) {
     for (let i = 0; i < unitsDesc.length; i++) {
-      let unit = unitsDesc[i];
-      let val = duration.as(unit);
+      const unit = unitsDesc[i];
+      const val = duration.as(unit);
       // find a unit that rounds neatly
       if (val >= 1 && Math.floor(val) === val) {
 
@@ -35,7 +35,7 @@ export default function () {
       }
     }
 
-    let ms = duration.as('ms');
+    const ms = duration.as('ms');
     return {
       value: ms,
       unit: 'ms',
diff --git a/src/ui/public/time_buckets/time_buckets.js b/src/ui/public/time_buckets/time_buckets.js
index aa3ead7760714..dfd74a3e4d279 100644
--- a/src/ui/public/time_buckets/time_buckets.js
+++ b/src/ui/public/time_buckets/time_buckets.js
@@ -6,9 +6,9 @@ import TimeBucketsCalcAutoIntervalProvider from 'ui/time_buckets/calc_auto_inter
 import TimeBucketsCalcEsIntervalProvider from 'ui/time_buckets/calc_es_interval';
 export default function IntervalHelperProvider(Private, timefilter, config) {
 
-  let calcAuto = Private(TimeBucketsCalcAutoIntervalProvider);
-  let calcEsInterval = Private(TimeBucketsCalcEsIntervalProvider);
-  let tzOffset = moment().format('Z');
+  const calcAuto = Private(TimeBucketsCalcAutoIntervalProvider);
+  const calcEsInterval = Private(TimeBucketsCalcEsIntervalProvider);
+  const tzOffset = moment().format('Z');
 
   function isValidMoment(m) {
     return m && ('isValid' in m) && m.isValid();
@@ -51,11 +51,11 @@ export default function IntervalHelperProvider(Private, timefilter, config) {
       bounds = _.isArray(input) ? input : [];
     }
 
-    let moments = _(bounds)
+    const moments = _(bounds)
     .map(_.ary(moment, 1))
     .sortBy(Number);
 
-    let valid = moments.size() === 2 && moments.every(isValidMoment);
+    const valid = moments.size() === 2 && moments.every(isValidMoment);
     if (!valid) {
       this.clearBounds();
       throw new Error('invalid bounds set: ' + input);
@@ -197,13 +197,13 @@ export default function IntervalHelperProvider(Private, timefilter, config) {
    * @return {[type]} [description]
    */
   TimeBuckets.prototype.getInterval = function () {
-    let self = this;
-    let duration = self.getDuration();
+    const self = this;
+    const duration = self.getDuration();
     return decorateInterval(maybeScaleInterval(readInterval()));
 
     // either pull the interval from state or calculate the auto-interval
     function readInterval() {
-      let interval = self._i;
+      const interval = self._i;
       if (moment.isDuration(interval)) return interval;
       return calcAuto.near(config.get('histogram:barTarget'), duration);
     }
@@ -212,8 +212,8 @@ export default function IntervalHelperProvider(Private, timefilter, config) {
     function maybeScaleInterval(interval) {
       if (!self.hasBounds()) return interval;
 
-      let maxLength = config.get('histogram:maxBars');
-      let approxLen = duration / interval;
+      const maxLength = config.get('histogram:maxBars');
+      const approxLen = duration / interval;
       let scaled;
 
       if (approxLen > maxLength) {
@@ -234,13 +234,13 @@ export default function IntervalHelperProvider(Private, timefilter, config) {
 
     // append some TimeBuckets specific props to the interval
     function decorateInterval(interval) {
-      let esInterval = calcEsInterval(interval);
+      const esInterval = calcEsInterval(interval);
       interval.esValue = esInterval.value;
       interval.esUnit = esInterval.unit;
       interval.expression = esInterval.expression;
       interval.overflow = duration > interval ? moment.duration(interval - duration) : false;
 
-      let prettyUnits = moment.normalizeUnits(esInterval.unit);
+      const prettyUnits = moment.normalizeUnits(esInterval.unit);
       if (esInterval.value === 1) {
         interval.description = prettyUnits;
       } else {
@@ -263,11 +263,11 @@ export default function IntervalHelperProvider(Private, timefilter, config) {
    * @return {string}
    */
   TimeBuckets.prototype.getScaledDateFormat = function () {
-    let interval = this.getInterval();
-    let rules = config.get('dateFormat:scaled');
+    const interval = this.getInterval();
+    const rules = config.get('dateFormat:scaled');
 
     for (let i = rules.length - 1; i >= 0; i--) {
-      let rule = rules[i];
+      const rule = rules[i];
       if (!rule[0] || interval >= moment.duration(rule[0])) {
         return rule[1];
       }
@@ -279,22 +279,22 @@ export default function IntervalHelperProvider(Private, timefilter, config) {
 
   TimeBuckets.__cached__ = function (self) {
     let cache = {};
-    let sameMoment = same(moment.isMoment);
-    let sameDuration = same(moment.isDuration);
+    const sameMoment = same(moment.isMoment);
+    const sameDuration = same(moment.isDuration);
 
-    let desc = {
+    const desc = {
       __cached__: {
         value: self
       },
     };
 
-    let breakers = {
+    const breakers = {
       setBounds: 'bounds',
       clearBounds: 'bounds',
       setInterval: 'interval'
     };
 
-    let resources = {
+    const resources = {
       bounds: {
         setup: function () {
           return [self._lb, self._ub];
@@ -326,16 +326,16 @@ export default function IntervalHelperProvider(Private, timefilter, config) {
     }
 
     function cacheBreaker(prop) {
-      let resource = resources[breakers[prop]];
-      let setup = resource.setup;
-      let changes = resource.changes;
-      let deps = resource.deps;
-      let fn = self[prop];
+      const resource = resources[breakers[prop]];
+      const setup = resource.setup;
+      const changes = resource.changes;
+      const deps = resource.deps;
+      const fn = self[prop];
 
       return {
         value: function cacheBreaker(input) {
-          let prev = setup.call(self);
-          let ret = fn.apply(self, arguments);
+          const prev = setup.call(self);
+          const ret = fn.apply(self, arguments);
 
           if (changes.call(self, prev)) {
             cache = {};
diff --git a/src/ui/public/timefilter/lib/diff_interval.js b/src/ui/public/timefilter/lib/diff_interval.js
index 9137e8d9dc65e..d37fe0885720d 100644
--- a/src/ui/public/timefilter/lib/diff_interval.js
+++ b/src/ui/public/timefilter/lib/diff_interval.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import UtilsDiffTimePickerValsProvider from 'ui/utils/diff_time_picker_vals';
 export default function diffTimeProvider(Private) {
-  let diff = Private(UtilsDiffTimePickerValsProvider);
+  const diff = Private(UtilsDiffTimePickerValsProvider);
 
   return function (self) {
     let oldRefreshInterval = _.clone(self.refreshInterval);
diff --git a/src/ui/public/timefilter/lib/diff_time.js b/src/ui/public/timefilter/lib/diff_time.js
index 39c1204cb46fe..cd482f17a47b6 100644
--- a/src/ui/public/timefilter/lib/diff_time.js
+++ b/src/ui/public/timefilter/lib/diff_time.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import UtilsDiffTimePickerValsProvider from 'ui/utils/diff_time_picker_vals';
 export default function diffTimeProvider(Private) {
-  let diff = Private(UtilsDiffTimePickerValsProvider);
+  const diff = Private(UtilsDiffTimePickerValsProvider);
 
   return function (self) {
     let oldTime = _.clone(self.time);
diff --git a/src/ui/public/timefilter/timefilter.js b/src/ui/public/timefilter/timefilter.js
index 257bbc8e54d68..0fdf57f964b86 100644
--- a/src/ui/public/timefilter/timefilter.js
+++ b/src/ui/public/timefilter/timefilter.js
@@ -19,11 +19,11 @@ uiRoutes
 uiModules
 .get('kibana')
 .service('timefilter', function (Private, globalState, $rootScope, config) {
-  let Events = Private(EventsProvider);
-  let diff = Private(UtilsDiffTimePickerValsProvider);
+  const Events = Private(EventsProvider);
+  const diff = Private(UtilsDiffTimePickerValsProvider);
 
   function convertISO8601(stringTime) {
-    let obj = moment(stringTime, 'YYYY-MM-DDTHH:mm:ss.SSSZ', true);
+    const obj = moment(stringTime, 'YYYY-MM-DDTHH:mm:ss.SSSZ', true);
     return obj.isValid() ? obj : stringTime;
   }
 
@@ -31,15 +31,15 @@ uiModules
   function Timefilter() {
     Timefilter.Super.call(this);
 
-    let self = this;
-    let diffTime = Private(TimefilterLibDiffTimeProvider)(self);
-    let diffInterval = Private(TimefilterLibDiffIntervalProvider)(self);
+    const self = this;
+    const diffTime = Private(TimefilterLibDiffTimeProvider)(self);
+    const diffInterval = Private(TimefilterLibDiffIntervalProvider)(self);
 
     self.enabled = false;
 
     self.init = _.once(function () {
-      let timeDefaults = config.get('timepicker:timeDefaults');
-      let refreshIntervalDefaults = config.get('timepicker:refreshIntervalDefaults');
+      const timeDefaults = config.get('timepicker:timeDefaults');
+      const refreshIntervalDefaults = config.get('timepicker:refreshIntervalDefaults');
 
       // These can be date math strings or moments.
       self.time = _.defaults(globalState.time || {}, timeDefaults);
@@ -47,8 +47,8 @@ uiModules
 
       globalState.on('fetch_with_changes', function () {
         // clone and default to {} in one
-        let newTime = _.defaults({}, globalState.time, timeDefaults);
-        let newRefreshInterval = _.defaults({}, globalState.refreshInterval, refreshIntervalDefaults);
+        const newTime = _.defaults({}, globalState.time, timeDefaults);
+        const newRefreshInterval = _.defaults({}, globalState.refreshInterval, refreshIntervalDefaults);
 
         if (newTime) {
           if (newTime.to) newTime.to = convertISO8601(newTime.to);
@@ -78,10 +78,10 @@ uiModules
 
   Timefilter.prototype.get = function (indexPattern) {
     let filter;
-    let timefield = indexPattern.timeFieldName && _.find(indexPattern.fields, {name: indexPattern.timeFieldName});
+    const timefield = indexPattern.timeFieldName && _.find(indexPattern.fields, {name: indexPattern.timeFieldName});
 
     if (timefield) {
-      let bounds = this.getBounds();
+      const bounds = this.getBounds();
       filter = {range : {}};
       filter.range[timefield.name] = {
         gte: bounds.min.valueOf(),
diff --git a/src/ui/public/timepicker/quick_ranges.js b/src/ui/public/timepicker/quick_ranges.js
index 78b7c33b3fcca..8a983f6a288be 100644
--- a/src/ui/public/timepicker/quick_ranges.js
+++ b/src/ui/public/timepicker/quick_ranges.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.constant('quickRanges', [
   { from: 'now/d',    to: 'now/d',    display: 'Today',                 section: 0 },
diff --git a/src/ui/public/timepicker/refresh_intervals.js b/src/ui/public/timepicker/refresh_intervals.js
index 3845f2110e685..ba9f9c77a86be 100644
--- a/src/ui/public/timepicker/refresh_intervals.js
+++ b/src/ui/public/timepicker/refresh_intervals.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.constant('refreshIntervals', [
   { value : 0, display: 'Off', section: 0},
diff --git a/src/ui/public/timepicker/time_units.js b/src/ui/public/timepicker/time_units.js
index da8960a2df646..73b53d16e09d7 100644
--- a/src/ui/public/timepicker/time_units.js
+++ b/src/ui/public/timepicker/time_units.js
@@ -1,5 +1,5 @@
 import uiModules from 'ui/modules';
-let module = uiModules.get('kibana');
+const module = uiModules.get('kibana');
 
 module.constant('timeUnits', {
   s: 'second',
diff --git a/src/ui/public/timepicker/timepicker.js b/src/ui/public/timepicker/timepicker.js
index b8494a2fe08cd..8d2b9648b88ef 100644
--- a/src/ui/public/timepicker/timepicker.js
+++ b/src/ui/public/timepicker/timepicker.js
@@ -10,8 +10,8 @@ import 'ui/timepicker/refresh_intervals';
 import 'ui/timepicker/time_units';
 import 'ui/timepicker/kbn_global_timepicker';
 import uiModules from 'ui/modules';
-let module = uiModules.get('ui/timepicker');
-let notify = new Notifier({
+const module = uiModules.get('ui/timepicker');
+const notify = new Notifier({
   location: 'timepicker',
 });
 
@@ -73,7 +73,7 @@ module.directive('kbnTimepicker', function (quickRanges, timeUnits, refreshInter
           case 'quick':
             break;
           case 'relative':
-            let fromParts = $scope.from.toString().split('-');
+            const fromParts = $scope.from.toString().split('-');
             let relativeParts = [];
 
             // Try to parse the relative time, if we can't use moment duration to guestimate
@@ -84,11 +84,11 @@ module.directive('kbnTimepicker', function (quickRanges, timeUnits, refreshInter
               $scope.relative.count = parseInt(relativeParts[1], 10);
               $scope.relative.unit = relativeParts[2];
             } else {
-              let duration = moment.duration(moment().diff(dateMath.parse($scope.from)));
-              let units = _.pluck(_.clone($scope.relativeOptions).reverse(), 'value');
+              const duration = moment.duration(moment().diff(dateMath.parse($scope.from)));
+              const units = _.pluck(_.clone($scope.relativeOptions).reverse(), 'value');
               if ($scope.from.toString().split('/')[1]) $scope.relative.round = true;
               for (let i = 0; i < units.length; i++) {
-                let as = duration.as(units[i]);
+                const as = duration.as(units[i]);
                 if (as > 1) {
                   $scope.relative.count = Math.round(as);
                   $scope.relative.unit = units[i];
@@ -120,7 +120,7 @@ module.directive('kbnTimepicker', function (quickRanges, timeUnits, refreshInter
       };
 
       $scope.formatRelative = function () {
-        let parsed = dateMath.parse(getRelativeString());
+        const parsed = dateMath.parse(getRelativeString());
         $scope.relative.preview =  parsed ? parsed.format($scope.format) : undefined;
         return parsed;
       };
diff --git a/src/ui/public/typeahead/_input.js b/src/ui/public/typeahead/_input.js
index 88d8130102b48..00297ed319439 100644
--- a/src/ui/public/typeahead/_input.js
+++ b/src/ui/public/typeahead/_input.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import 'ui/notify/directives';
 import uiModules from 'ui/modules';
-let typeahead = uiModules.get('kibana/typeahead');
+const typeahead = uiModules.get('kibana/typeahead');
 
 
 typeahead.directive('kbnTypeaheadInput', function ($rootScope) {
@@ -11,8 +11,8 @@ typeahead.directive('kbnTypeaheadInput', function ($rootScope) {
     require: ['^ngModel', '^kbnTypeahead'],
 
     link: function ($scope, $el, $attr, deps) {
-      let model = deps[0];
-      let typeaheadCtrl = deps[1];
+      const model = deps[0];
+      const typeaheadCtrl = deps[1];
 
       typeaheadCtrl.setInputModel(model);
 
diff --git a/src/ui/public/typeahead/_items.js b/src/ui/public/typeahead/_items.js
index 9f2bf9941c0e1..d2bf04c46e30a 100644
--- a/src/ui/public/typeahead/_items.js
+++ b/src/ui/public/typeahead/_items.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import listTemplate from 'ui/typeahead/partials/typeahead-items.html';
 import 'ui/notify/directives';
 import uiModules from 'ui/modules';
-let typeahead = uiModules.get('kibana/typeahead');
+const typeahead = uiModules.get('kibana/typeahead');
 
 
 typeahead.directive('kbnTypeaheadItems', function () {
diff --git a/src/ui/public/typeahead/typeahead.js b/src/ui/public/typeahead/typeahead.js
index a97ffd4f6f634..bd14d6c9e5528 100644
--- a/src/ui/public/typeahead/typeahead.js
+++ b/src/ui/public/typeahead/typeahead.js
@@ -3,11 +3,11 @@ import 'ui/typeahead/typeahead.less';
 import 'ui/typeahead/_input';
 import 'ui/typeahead/_items';
 import uiModules from 'ui/modules';
-let typeahead = uiModules.get('kibana/typeahead');
+const typeahead = uiModules.get('kibana/typeahead');
 
 
 typeahead.directive('kbnTypeahead', function () {
-  let keyMap = {
+  const keyMap = {
     ESC: 27,
     UP: 38,
     DOWN: 40,
@@ -23,7 +23,7 @@ typeahead.directive('kbnTypeahead', function () {
     controllerAs: 'typeahead',
 
     controller: function ($scope, $element, $timeout, PersistedLog, config) {
-      let self = this;
+      const self = this;
       self.form = $element.closest('form');
       self.query = '';
       self.hidden = true;
@@ -138,7 +138,7 @@ typeahead.directive('kbnTypeahead', function () {
       };
 
       self.keypressHandler = function (ev) {
-        let keyCode = ev.which || ev.keyCode;
+        const keyCode = ev.which || ev.keyCode;
 
         if (self.focused) {
           self.hidden = false;
@@ -194,11 +194,11 @@ typeahead.directive('kbnTypeahead', function () {
         }
 
         // update the filteredItems using the query
-        let beginningMatches = $scope.items.filter(function (item) {
+        const beginningMatches = $scope.items.filter(function (item) {
           return item.indexOf(query) === 0;
         });
 
-        let otherMatches = $scope.items.filter(function (item) {
+        const otherMatches = $scope.items.filter(function (item) {
           return item.indexOf(query) > 0;
         });
 
diff --git a/src/ui/public/url/__tests__/url.js b/src/ui/public/url/__tests__/url.js
index 57f2483b7beb4..98e72b6d61f47 100644
--- a/src/ui/public/url/__tests__/url.js
+++ b/src/ui/public/url/__tests__/url.js
@@ -72,7 +72,7 @@ describe('kbnUrl', function () {
         }
       };
 
-      let unbind = sinon.stub();
+      const unbind = sinon.stub();
       sinon.stub($rootScope, '$on').returns(unbind);
       $route.reload = sinon.stub();
 
@@ -80,7 +80,7 @@ describe('kbnUrl', function () {
       kbnUrl.change('/url');
       expect($rootScope.$on.callCount).to.be(1);
 
-      let handler = $rootScope.$on.firstCall.args[1];
+      const handler = $rootScope.$on.firstCall.args[1];
       handler();
       expect(unbind.callCount).to.be(1);
       expect($route.reload.callCount).to.be(1);
@@ -142,9 +142,9 @@ describe('kbnUrl', function () {
     });
 
     it('should uri encode replaced params', function () {
-      let url = '/some/path/';
-      let params = { replace: faker.Lorem.words(3).join(' ') };
-      let check = encodeURIComponent(params.replace);
+      const url = '/some/path/';
+      const params = { replace: faker.Lorem.words(3).join(' ') };
+      const check = encodeURIComponent(params.replace);
       sinon.stub($location, 'url');
 
       kbnUrl.change(url + '{{replace}}', params);
@@ -154,22 +154,22 @@ describe('kbnUrl', function () {
 
     it('should parse angular expression in substitutions and uri encode the results', function () {
       // build url by piecing together these parts
-      let urlParts = ['/', '/', '?', '&', '#'];
+      const urlParts = ['/', '/', '?', '&', '#'];
       // make sure it can parse templates with weird spacing
-      let wrappers = [ ['{{', '}}'], ['{{ ', ' }}'], ['{{', '  }}'], ['{{    ', '}}'], ['{{    ', '         }}']];
+      const wrappers = [ ['{{', '}}'], ['{{ ', ' }}'], ['{{', '  }}'], ['{{    ', '}}'], ['{{    ', '         }}']];
       // make sure filters are evaluated via angular expressions
-      let objIndex = 4; // used to case one replace as an object
-      let filters = ['', 'uppercase', '', 'uppercase', 'rison'];
+      const objIndex = 4; // used to case one replace as an object
+      const filters = ['', 'uppercase', '', 'uppercase', 'rison'];
 
       // the words (template keys) used must all be unique
-      let words = _.uniq(faker.Lorem.words(10)).slice(0, urlParts.length).map(function (word, i) {
+      const words = _.uniq(faker.Lorem.words(10)).slice(0, urlParts.length).map(function (word, i) {
         if (filters[i].length) {
           return word + '|' + filters[i];
         }
         return word;
       });
 
-      let replacements = faker.Lorem.words(urlParts.length).map(function (word, i) {
+      const replacements = faker.Lorem.words(urlParts.length).map(function (word, i) {
         // make selected replacement into an object
         if (i === objIndex) {
           return { replace: word };
@@ -183,15 +183,15 @@ describe('kbnUrl', function () {
       let testUrl = '';
       urlParts.forEach(function (part, i) {
         url += part + wrappers[i][0] + words[i] + wrappers[i][1];
-        let locals = {};
+        const locals = {};
         locals[words[i].split('|')[0]] = replacements[i];
         testUrl += part + encodeURIComponent($rootScope.$eval(words[i], locals));
       });
 
       // create the locals replacement object
-      let params = {};
+      const params = {};
       replacements.forEach(function (replacement, i) {
-        let word = words[i].split('|')[0];
+        const word = words[i].split('|')[0];
         params[word] = replacement;
       });
 
@@ -204,7 +204,7 @@ describe('kbnUrl', function () {
     });
 
     it('should handle dot notation', function () {
-      let url = '/some/thing/{{that.is.substituted}}';
+      const url = '/some/thing/{{that.is.substituted}}';
 
       kbnUrl.change(url, {
         that: {
@@ -218,8 +218,8 @@ describe('kbnUrl', function () {
     });
 
     it('should throw when params are missing', function () {
-      let url = '/{{replace_me}}';
-      let params = {};
+      const url = '/{{replace_me}}';
+      const params = {};
 
       try {
         kbnUrl.change(url, params);
@@ -231,8 +231,8 @@ describe('kbnUrl', function () {
     });
 
     it('should throw when filtered params are missing', function () {
-      let url = '/{{replace_me|number}}';
-      let params = {};
+      const url = '/{{replace_me|number}}';
+      const params = {};
 
       try {
         kbnUrl.change(url, params);
@@ -244,10 +244,10 @@ describe('kbnUrl', function () {
     });
 
     it('should change the entire url', function () {
-      let path = '/test/path';
-      let search = {search: 'test'};
-      let hash = 'hash';
-      let newPath = '/new/location';
+      const path = '/test/path';
+      const search = {search: 'test'};
+      const hash = 'hash';
+      const newPath = '/new/location';
 
       $location.path(path).search(search).hash(hash);
 
@@ -265,10 +265,10 @@ describe('kbnUrl', function () {
     });
 
     it('should allow setting app state on the target url', function () {
-      let path = '/test/path';
-      let search = {search: 'test'};
-      let hash = 'hash';
-      let newPath = '/new/location';
+      const path = '/test/path';
+      const search = {search: 'test'};
+      const hash = 'hash';
+      const newPath = '/new/location';
 
       $location.path(path).search(search).hash(hash);
 
@@ -288,10 +288,10 @@ describe('kbnUrl', function () {
 
   describe('changePath', function () {
     it('should change just the path', function () {
-      let path = '/test/path';
-      let search = {search: 'test'};
-      let hash = 'hash';
-      let newPath = '/new/location';
+      const path = '/test/path';
+      const search = {search: 'test'};
+      const hash = 'hash';
+      const newPath = '/new/location';
 
       $location.path(path).search(search).hash(hash);
 
@@ -311,10 +311,10 @@ describe('kbnUrl', function () {
 
   describe('redirect', function () {
     it('should change the entire url', function () {
-      let path = '/test/path';
-      let search = {search: 'test'};
-      let hash = 'hash';
-      let newPath = '/new/location';
+      const path = '/test/path';
+      const search = {search: 'test'};
+      const hash = 'hash';
+      const newPath = '/new/location';
 
       $location.path(path).search(search).hash(hash);
 
@@ -332,10 +332,10 @@ describe('kbnUrl', function () {
     });
 
     it('should allow setting app state on the target url', function () {
-      let path = '/test/path';
-      let search = {search: 'test'};
-      let hash = 'hash';
-      let newPath = '/new/location';
+      const path = '/test/path';
+      const search = {search: 'test'};
+      const hash = 'hash';
+      const newPath = '/new/location';
 
       $location.path(path).search(search).hash(hash);
 
@@ -373,10 +373,10 @@ describe('kbnUrl', function () {
 
   describe('redirectPath', function () {
     it('should only change the path', function () {
-      let path = '/test/path';
-      let search = {search: 'test'};
-      let hash = 'hash';
-      let newPath = '/new/location';
+      const path = '/test/path';
+      const search = {search: 'test'};
+      const hash = 'hash';
+      const newPath = '/new/location';
 
       $location
         .path(path)
diff --git a/src/ui/public/url/url.js b/src/ui/public/url/url.js
index ef2442730db7e..9c7c17214f664 100644
--- a/src/ui/public/url/url.js
+++ b/src/ui/public/url/url.js
@@ -9,7 +9,7 @@ uiModules.get('kibana/url')
 .service('kbnUrl', function (Private) { return Private(KbnUrlProvider); });
 
 function KbnUrlProvider($injector, $location, $rootScope, $parse, Private) {
-  let self = this;
+  const self = this;
 
   /**
    * Navigate to a url
@@ -71,10 +71,10 @@ function KbnUrlProvider($injector, $location, $rootScope, $parse, Private) {
 
     return template.replace(/\{\{([^\}]+)\}\}/g, function (match, expr) {
       // remove filters
-      let key = expr.split('|')[0].trim();
+      const key = expr.split('|')[0].trim();
 
       // verify that the expression can be evaluated
-      let p = $parse(key)(paramObj);
+      const p = $parse(key)(paramObj);
 
       // if evaluation can't be made, throw
       if (_.isUndefined(p)) {
@@ -110,7 +110,7 @@ function KbnUrlProvider($injector, $location, $rootScope, $parse, Private) {
    * @return {string} - the computed url
    */
   self.getRouteUrl = function (obj, route) {
-    let template = obj && obj.routes && obj.routes[route];
+    const template = obj && obj.routes && obj.routes[route];
     if (template) return self.eval(template, obj);
   };
 
@@ -144,7 +144,7 @@ function KbnUrlProvider($injector, $location, $rootScope, $parse, Private) {
   let reloading;
 
   self._changeLocation = function (type, url, paramObj, replace, appState) {
-    let prev = {
+    const prev = {
       path: $location.path(),
       search: $location.search()
     };
@@ -157,7 +157,7 @@ function KbnUrlProvider($injector, $location, $rootScope, $parse, Private) {
       $location.search('_a', rison.encode(appState));
     }
 
-    let next = {
+    const next = {
       path: $location.path(),
       search: $location.search()
     };
@@ -183,13 +183,13 @@ function KbnUrlProvider($injector, $location, $rootScope, $parse, Private) {
   self._shouldAutoReload = function (next, prev, $route) {
     if (reloading) return false;
 
-    let route = $route.current && $route.current.$$route;
+    const route = $route.current && $route.current.$$route;
     if (!route) return false;
 
     if (next.path !== prev.path) return false;
 
-    let reloadOnSearch = route.reloadOnSearch;
-    let searchSame = _.isEqual(next.search, prev.search);
+    const reloadOnSearch = route.reloadOnSearch;
+    const searchSame = _.isEqual(next.search, prev.search);
 
     return (reloadOnSearch && searchSame) || !reloadOnSearch;
   };
diff --git a/src/ui/public/utils/__tests__/add_word_breaks.js b/src/ui/public/utils/__tests__/add_word_breaks.js
index 594029f7e4045..c120df81d7a23 100644
--- a/src/ui/public/utils/__tests__/add_word_breaks.js
+++ b/src/ui/public/utils/__tests__/add_word_breaks.js
@@ -4,7 +4,7 @@ import addWordBreaks from 'ui/utils/add_word_breaks';
 
 describe('addWordBreaks', function () {
 
-  let fixtures = [
+  const fixtures = [
     ['aaaaaaaaaaaaaaaaaaaa', 'aaaaaaaaaaa<wbr>aaaaaaaaa'],
     ['aaaa aaaaaaaaaaaaaaa', 'aaaa aaaaaaaaaaa<wbr>aaaa'],
     ['aaaa;aaaaaaaaaaaaaaa', 'aaaa;aaaaaaaaaaa<wbr>aaaa'],
@@ -16,9 +16,9 @@ describe('addWordBreaks', function () {
   ];
 
   _.each(fixtures, function (fixture) {
-    let msg = 'should convert ' + fixture[0] + ' to ' + fixture[1];
+    const msg = 'should convert ' + fixture[0] + ' to ' + fixture[1];
     it(msg, function () {
-      let results = addWordBreaks(fixture[0], 10);
+      const results = addWordBreaks(fixture[0], 10);
       expect(results).to.be(fixture[1]);
     });
   });
diff --git a/src/ui/public/utils/__tests__/diff_object.js b/src/ui/public/utils/__tests__/diff_object.js
index 9ae29007ad3c0..d96e7e672fb10 100644
--- a/src/ui/public/utils/__tests__/diff_object.js
+++ b/src/ui/public/utils/__tests__/diff_object.js
@@ -5,70 +5,70 @@ import _ from 'lodash';
 describe('ui/utils/diff_object', function () {
 
   it('should list the removed keys', function () {
-    let target = { test: 'foo' };
-    let source = { foo: 'test' };
-    let results = diff(target, source);
+    const target = { test: 'foo' };
+    const source = { foo: 'test' };
+    const results = diff(target, source);
     expect(results).to.have.property('removed');
     expect(results.removed).to.eql(['test']);
   });
 
   it('should list the changed keys', function () {
-    let target = { foo: 'bar' };
-    let source = { foo: 'test' };
-    let results = diff(target, source);
+    const target = { foo: 'bar' };
+    const source = { foo: 'test' };
+    const results = diff(target, source);
     expect(results).to.have.property('changed');
     expect(results.changed).to.eql(['foo']);
   });
 
   it('should list the added keys', function () {
-    let target = { };
-    let source = { foo: 'test' };
-    let results = diff(target, source);
+    const target = { };
+    const source = { foo: 'test' };
+    const results = diff(target, source);
     expect(results).to.have.property('added');
     expect(results.added).to.eql(['foo']);
   });
 
   it('should list all the keys that are change or removed', function () {
-    let target = { foo: 'bar', test: 'foo' };
-    let source = { foo: 'test' };
-    let results = diff(target, source);
+    const target = { foo: 'bar', test: 'foo' };
+    const source = { foo: 'test' };
+    const results = diff(target, source);
     expect(results).to.have.property('keys');
     expect(results.keys).to.eql(['foo', 'test']);
   });
 
   it('should ignore functions', function () {
-    let target = { foo: 'bar', test: 'foo' };
-    let source = { foo: 'test', fn: _.noop };
+    const target = { foo: 'bar', test: 'foo' };
+    const source = { foo: 'test', fn: _.noop };
     diff(target, source);
     expect(target).to.not.have.property('fn');
   });
 
   it('should ignore underscores', function () {
-    let target = { foo: 'bar', test: 'foo' };
-    let source = { foo: 'test', _private: 'foo' };
+    const target = { foo: 'bar', test: 'foo' };
+    const source = { foo: 'test', _private: 'foo' };
     diff(target, source);
     expect(target).to.not.have.property('_private');
   });
 
   it('should ignore dollar signs', function () {
-    let target = { foo: 'bar', test: 'foo' };
-    let source = { foo: 'test', $private: 'foo' };
+    const target = { foo: 'bar', test: 'foo' };
+    const source = { foo: 'test', $private: 'foo' };
     diff(target, source);
     expect(target).to.not.have.property('$private');
   });
 
   it('should not list any changes for similar objects', function () {
-    let target = { foo: 'bar', test: 'foo' };
-    let source = { foo: 'bar', test: 'foo', $private: 'foo' };
-    let results = diff(target, source);
+    const target = { foo: 'bar', test: 'foo' };
+    const source = { foo: 'bar', test: 'foo', $private: 'foo' };
+    const results = diff(target, source);
     expect(results.changed).to.be.empty();
   });
 
   it('should only change keys that actually changed', function () {
-    let obj = { 'message': 'foo' };
-    let target = { obj: obj, message: 'foo' };
-    let source = { obj: _.cloneDeep(obj), message: 'test' };
-    let results = diff(target, source);
+    const obj = { 'message': 'foo' };
+    const target = { obj: obj, message: 'foo' };
+    const source = { obj: _.cloneDeep(obj), message: 'test' };
+    const results = diff(target, source);
     expect(target.obj).to.be(obj);
   });
 
diff --git a/src/ui/public/utils/__tests__/diff_time_picker_vals.js b/src/ui/public/utils/__tests__/diff_time_picker_vals.js
index 3fa98ac573c2f..5e0d4c4c5d902 100644
--- a/src/ui/public/utils/__tests__/diff_time_picker_vals.js
+++ b/src/ui/public/utils/__tests__/diff_time_picker_vals.js
@@ -13,13 +13,13 @@ describe('Diff Time Picker Values', function () {
   }));
 
   it('accepts two undefined values', function () {
-    let diff = diffTimePickerValues(undefined, undefined);
+    const diff = diffTimePickerValues(undefined, undefined);
     expect(diff).to.be(false);
   });
 
   describe('dateMath ranges', function () {
     it('knows a match', function () {
-      let diff = diffTimePickerValues(
+      const diff = diffTimePickerValues(
         {
           to: 'now',
           from: 'now-7d'
@@ -33,7 +33,7 @@ describe('Diff Time Picker Values', function () {
       expect(diff).to.be(false);
     });
     it('knows a difference', function () {
-      let diff = diffTimePickerValues(
+      const diff = diffTimePickerValues(
         {
           to: 'now',
           from: 'now-7d'
@@ -50,7 +50,7 @@ describe('Diff Time Picker Values', function () {
 
   describe('a dateMath range, and a moment range', function () {
     it('is always different', function () {
-      let diff = diffTimePickerValues(
+      const diff = diffTimePickerValues(
         {
           to: moment(),
           from: moment()
@@ -67,10 +67,10 @@ describe('Diff Time Picker Values', function () {
 
   describe('moment ranges', function () {
     it('uses the time value of moments for comparison', function () {
-      let to = moment();
-      let from = moment().add(1, 'day');
+      const to = moment();
+      const from = moment().add(1, 'day');
 
-      let diff = diffTimePickerValues(
+      const diff = diffTimePickerValues(
         {
           to: to.clone(),
           from: from.clone()
@@ -85,11 +85,11 @@ describe('Diff Time Picker Values', function () {
     });
 
     it('fails if any to or from is different', function () {
-      let to = moment();
-      let from = moment().add(1, 'day');
-      let from2 = moment().add(2, 'day');
+      const to = moment();
+      const from = moment().add(1, 'day');
+      const from2 = moment().add(2, 'day');
 
-      let diff = diffTimePickerValues(
+      const diff = diffTimePickerValues(
         {
           to: to.clone(),
           from: from.clone()
@@ -105,7 +105,7 @@ describe('Diff Time Picker Values', function () {
   });
 
   it('does not fall apart with unusual values', function () {
-    let diff = diffTimePickerValues({}, {});
+    const diff = diffTimePickerValues({}, {});
     expect(diff).to.be(false);
   });
 });
diff --git a/src/ui/public/utils/__tests__/obj_define.js b/src/ui/public/utils/__tests__/obj_define.js
index fb4588fd0922d..7a8575b3985bd 100644
--- a/src/ui/public/utils/__tests__/obj_define.js
+++ b/src/ui/public/utils/__tests__/obj_define.js
@@ -9,10 +9,10 @@ describe('ObjDefine Utility', function () {
 
   describe('#writ', function () {
     it('creates writeable properties', function () {
-      let def = new ObjDefine();
+      const def = new ObjDefine();
       def.writ('name', 'foo');
 
-      let obj = def.create();
+      const obj = def.create();
       expect(obj).to.have.property('name', 'foo');
 
       obj.name = 'bar';
@@ -20,13 +20,13 @@ describe('ObjDefine Utility', function () {
     });
 
     it('exports the property to JSON', function () {
-      let def = new ObjDefine();
+      const def = new ObjDefine();
       def.writ('name', 'foo');
       expect(flatten(def.create())).to.have.property('name', 'foo');
     });
 
     it('does not export property to JSON it it\'s undefined or null', function () {
-      let def = new ObjDefine();
+      const def = new ObjDefine();
       def.writ('name');
       expect(flatten(def.create())).to.not.have.property('name');
 
@@ -35,10 +35,10 @@ describe('ObjDefine Utility', function () {
     });
 
     it('switched to exporting if a value is written', function () {
-      let def = new ObjDefine();
+      const def = new ObjDefine();
       def.writ('name');
 
-      let obj = def.create();
+      const obj = def.create();
       expect(flatten(obj)).to.not.have.property('name');
 
       obj.name = null;
@@ -49,10 +49,10 @@ describe('ObjDefine Utility', function () {
     });
 
     it('setting a writ value to null prevents it from exporting', function () {
-      let def = new ObjDefine();
+      const def = new ObjDefine();
       def.writ('name', 'foo');
 
-      let obj = def.create();
+      const obj = def.create();
       expect(flatten(obj)).to.have.property('name', 'foo');
 
       obj.name = null;
@@ -63,11 +63,11 @@ describe('ObjDefine Utility', function () {
 
   describe('#fact', function () {
     it('creates an immutable field', function () {
-      let def = new ObjDefine();
-      let val = 'foo';
-      let notval = 'bar';
+      const def = new ObjDefine();
+      const val = 'foo';
+      const notval = 'bar';
       def.fact('name', val);
-      let obj = def.create();
+      const obj = def.create();
 
 
       obj.name = notval; // UPDATE SHOULD BE IGNORED
@@ -75,7 +75,7 @@ describe('ObjDefine Utility', function () {
     });
 
     it('exports the fact to JSON', function () {
-      let def = new ObjDefine();
+      const def = new ObjDefine();
       def.fact('name', 'foo');
       expect(flatten(def.create())).to.have.property('name', 'foo');
     });
@@ -83,11 +83,11 @@ describe('ObjDefine Utility', function () {
 
   describe('#comp', function () {
     it('creates an immutable field', function () {
-      let def = new ObjDefine();
-      let val = 'foo';
-      let notval = 'bar';
+      const def = new ObjDefine();
+      const val = 'foo';
+      const notval = 'bar';
       def.comp('name', val);
-      let obj = def.create();
+      const obj = def.create();
 
       expect(function () {
         'use strict'; // eslint-disable-line strict
@@ -97,7 +97,7 @@ describe('ObjDefine Utility', function () {
     });
 
     it('does not export the computed value to JSON', function () {
-      let def = new ObjDefine();
+      const def = new ObjDefine();
       def.comp('name', 'foo');
       expect(flatten(def.create())).to.not.have.property('name');
     });
@@ -108,24 +108,24 @@ describe('ObjDefine Utility', function () {
     it('creates object that inherits from the prototype', function () {
       function SomeClass() {}
 
-      let def = new ObjDefine(null, SomeClass.prototype);
-      let obj = def.create();
+      const def = new ObjDefine(null, SomeClass.prototype);
+      const obj = def.create();
 
       expect(obj).to.be.a(SomeClass);
     });
 
     it('uses the defaults for property values', function () {
-      let def = new ObjDefine({ name: 'bar' });
+      const def = new ObjDefine({ name: 'bar' });
       def.fact('name');
 
-      let obj = def.create();
+      const obj = def.create();
 
       expect(obj).to.have.property('name', 'bar');
     });
 
     it('ignores default values that are not defined propertyes', function () {
-      let def = new ObjDefine({ name: 'foo', name2: 'bar' });
-      let obj = def.create();
+      const def = new ObjDefine({ name: 'foo', name2: 'bar' });
+      const obj = def.create();
 
       expect(obj).to.not.have.property('name');
       expect(obj).to.not.have.property('name2');
diff --git a/src/ui/public/utils/__tests__/ordinal_suffix.js b/src/ui/public/utils/__tests__/ordinal_suffix.js
index 1fc5c716ca646..0d545d86a04d6 100644
--- a/src/ui/public/utils/__tests__/ordinal_suffix.js
+++ b/src/ui/public/utils/__tests__/ordinal_suffix.js
@@ -3,7 +3,7 @@ import addOrdinalSuffix from 'ui/utils/ordinal_suffix';
 import expect from 'expect.js';
 
 describe('ordinal suffix util', function () {
-  let checks = {
+  const checks = {
     1: 'st',
     2: 'nd',
     3: 'rd',
@@ -37,8 +37,8 @@ describe('ordinal suffix util', function () {
   };
 
   _.forOwn(checks, function (expected, num) {
-    let int = parseInt(num, 10);
-    let float = int + Math.random();
+    const int = parseInt(num, 10);
+    const float = int + Math.random();
 
     it('knowns ' + int, function () {
       expect(addOrdinalSuffix(num)).to.be(num + '' + expected);
diff --git a/src/ui/public/utils/__tests__/range.js b/src/ui/public/utils/__tests__/range.js
index de403fc61728d..0b835845cffb6 100644
--- a/src/ui/public/utils/__tests__/range.js
+++ b/src/ui/public/utils/__tests__/range.js
@@ -25,7 +25,7 @@ describe('Range parsing utility', function () {
     }).to.throwException(TypeError);
   });
 
-  let tests = {
+  const tests = {
     '[ 0 , 100 ]': {
       props: {
         min: 0,
@@ -92,7 +92,7 @@ describe('Range parsing utility', function () {
   _.forOwn(tests, function (spec, str) {
 
     describe(str, function () {
-      let range = parse(str);
+      const range = parse(str);
 
       it('creation', function () {
         expect(range).to.eql(spec.props);
diff --git a/src/ui/public/utils/__tests__/scanner.js b/src/ui/public/utils/__tests__/scanner.js
index 1d3feb196a36d..581fdcfa035a3 100644
--- a/src/ui/public/utils/__tests__/scanner.js
+++ b/src/ui/public/utils/__tests__/scanner.js
@@ -41,8 +41,8 @@ describe('Scanner', function () {
     let search;
     let scroll;
     let scanner;
-    let mockSearch = {'_scroll_id':'abc','took':1,'timed_out':false,'_shards':{'total':1,'successful':1,'failed':0},'hits':{'total':2,'max_score':0.0,'hits':[]}}; // eslint-disable-line max-len
-    let mockScroll = {'took':1,'timed_out':false,'_shards':{'total':1,'successful':1,'failed':0},'hits':{'total':2,'max_score':0.0,'hits':['one', 'two']}}; // eslint-disable-line max-len
+    const mockSearch = {'_scroll_id':'abc','took':1,'timed_out':false,'_shards':{'total':1,'successful':1,'failed':0},'hits':{'total':2,'max_score':0.0,'hits':[]}}; // eslint-disable-line max-len
+    const mockScroll = {'took':1,'timed_out':false,'_shards':{'total':1,'successful':1,'failed':0},'hits':{'total':2,'max_score':0.0,'hits':['one', 'two']}}; // eslint-disable-line max-len
 
     beforeEach(function () {
       scanner = new Scanner(es, {
@@ -96,7 +96,7 @@ describe('Scanner', function () {
 
     it('should scroll across multiple pages', function () {
       scroll.restore();
-      let oneResult = {'took':1,'timed_out':false,'_shards':{'total':1,'successful':1,'failed':0},'hits':{'total':2,'max_score':0.0,'hits':['one']}}; // eslint-disable-line max-len
+      const oneResult = {'took':1,'timed_out':false,'_shards':{'total':1,'successful':1,'failed':0},'hits':{'total':2,'max_score':0.0,'hits':['one']}}; // eslint-disable-line max-len
       scroll = sinon.stub(scanner.client, 'scroll', (req, cb) => cb(null, oneResult));
       return scanner.scanAndMap(null, {pageSize: 1})
       .then(function (response) {
diff --git a/src/ui/public/utils/__tests__/sequencer.js b/src/ui/public/utils/__tests__/sequencer.js
index ef03a16b8f939..3a163ff6ad76e 100644
--- a/src/ui/public/utils/__tests__/sequencer.js
+++ b/src/ui/public/utils/__tests__/sequencer.js
@@ -3,7 +3,7 @@ import sequencer from 'ui/utils/sequencer';
 import expect from 'expect.js';
 describe('sequencer util', function () {
 
-  let opts = [
+  const opts = [
     { min: 500, max: 7500, length: 1500 },
     { min: 50, max: 500, length: 1000 },
     { min: 5, max: 50, length: 100 }
diff --git a/src/ui/public/utils/__tests__/simple_emitter.js b/src/ui/public/utils/__tests__/simple_emitter.js
index 41518bbe877d9..1d8aee66f1d52 100644
--- a/src/ui/public/utils/__tests__/simple_emitter.js
+++ b/src/ui/public/utils/__tests__/simple_emitter.js
@@ -40,7 +40,7 @@ describe('SimpleEmitter class', function () {
 
   describe('#on', function () {
     it('registers a handler', function () {
-      let handler = sinon.stub();
+      const handler = sinon.stub();
       emitter.on('a', handler);
       expect(emitter.listenerCount('a')).to.be(1);
 
@@ -56,7 +56,7 @@ describe('SimpleEmitter class', function () {
     });
 
     it('allows the same function to be registered multiple times', function () {
-      let handler = function () {};
+      const handler = function () {};
       emitter.on('a', handler);
       expect(emitter.listenerCount()).to.be(1);
       emitter.on('a', handler);
@@ -66,7 +66,7 @@ describe('SimpleEmitter class', function () {
 
   describe('#off', function () {
     it('removes a listener if it was registered', function () {
-      let handler = sinon.stub();
+      const handler = sinon.stub();
       expect(emitter.listenerCount()).to.be(0);
       emitter.on('a', handler);
       expect(emitter.listenerCount('a')).to.be(1);
@@ -94,11 +94,11 @@ describe('SimpleEmitter class', function () {
   describe('#emit', function () {
     it('calls the handlers in the order they were defined', function () {
       let i = 0;
-      let incr = function () { return ++i; };
-      let one = sinon.spy(incr);
-      let two = sinon.spy(incr);
-      let three = sinon.spy(incr);
-      let four = sinon.spy(incr);
+      const incr = function () { return ++i; };
+      const one = sinon.spy(incr);
+      const two = sinon.spy(incr);
+      const three = sinon.spy(incr);
+      const four = sinon.spy(incr);
 
       emitter
       .on('a', one)
@@ -122,11 +122,11 @@ describe('SimpleEmitter class', function () {
 
     it('always emits the handlers that were initially registered', function () {
 
-      let destructive = sinon.spy(function () {
+      const destructive = sinon.spy(function () {
         emitter.removeAllListeners();
         expect(emitter.listenerCount()).to.be(0);
       });
-      let stub = sinon.stub();
+      const stub = sinon.stub();
 
       emitter.on('run', destructive).on('run', stub).emit('run');
 
diff --git a/src/ui/public/utils/__tests__/slugify_id.js b/src/ui/public/utils/__tests__/slugify_id.js
index 57f7f2181501b..d28b46fac20ab 100644
--- a/src/ui/public/utils/__tests__/slugify_id.js
+++ b/src/ui/public/utils/__tests__/slugify_id.js
@@ -4,7 +4,7 @@ import expect from 'expect.js';
 
 describe('slugifyId()', function () {
 
-  let fixtures = [
+  const fixtures = [
     ['test/test', 'test-slash-test'],
     ['test?test', 'test-questionmark-test'],
     ['test=test', 'test-equal-test'],
@@ -28,9 +28,9 @@ describe('slugifyId()', function () {
   ];
 
   _.each(fixtures, function (fixture) {
-    let msg = 'should convert ' + fixture[0] + ' to ' + fixture[1];
+    const msg = 'should convert ' + fixture[0] + ' to ' + fixture[1];
     it(msg, function () {
-      let results = slugifyId(fixture[0]);
+      const results = slugifyId(fixture[0]);
       expect(results).to.be(fixture[1]);
     });
   });
diff --git a/src/ui/public/utils/add_word_breaks.js b/src/ui/public/utils/add_word_breaks.js
index 6f2454e93ebe4..bac266768480c 100644
--- a/src/ui/public/utils/add_word_breaks.js
+++ b/src/ui/public/utils/add_word_breaks.js
@@ -7,7 +7,7 @@ define(function () {
     let inHtmlChar = false;
 
     for (let i = 0, len = text.length; i < len; i++) {
-      let chr = text.charAt(i);
+      const chr = text.charAt(i);
       newText += chr;
 
       switch (chr) {
diff --git a/src/ui/public/utils/brush_event.js b/src/ui/public/utils/brush_event.js
index 9ecdc074d784d..b12ba26d0bd4f 100644
--- a/src/ui/public/utils/brush_event.js
+++ b/src/ui/public/utils/brush_event.js
@@ -1,8 +1,8 @@
 import moment from 'moment';
 export default function brushEventProvider(timefilter) {
   return function (event) {
-    let from = moment(event.range[0]);
-    let to = moment(event.range[1]);
+    const from = moment(event.range[0]);
+    const to = moment(event.range[1]);
 
     if (to - from === 0) return;
 
diff --git a/src/ui/public/utils/cidr_mask.js b/src/ui/public/utils/cidr_mask.js
index a0ae16709538c..5bc8ff8174e61 100644
--- a/src/ui/public/utils/cidr_mask.js
+++ b/src/ui/public/utils/cidr_mask.js
@@ -1,12 +1,12 @@
 import Ipv4Address from 'ui/utils/ipv4_address';
-let NUM_BITS = 32;
+const NUM_BITS = 32;
 
 function throwError(mask) {
   throw Error('Invalid CIDR mask: ' + mask);
 }
 
 function CidrMask(mask) {
-  let splits = mask.split('\/');
+  const splits = mask.split('\/');
   if (splits.length !== 2) throwError(mask);
   this.initialAddress = new Ipv4Address(splits[0]);
   this.prefixLength = Number(splits[1]);
@@ -14,9 +14,9 @@ function CidrMask(mask) {
 }
 
 CidrMask.prototype.getRange = function () {
-  let variableBits = NUM_BITS - this.prefixLength;
-  let fromAddress = this.initialAddress.valueOf() >> variableBits << variableBits >>> 0; // >>> 0 coerces to unsigned
-  let numAddresses = Math.pow(2, variableBits);
+  const variableBits = NUM_BITS - this.prefixLength;
+  const fromAddress = this.initialAddress.valueOf() >> variableBits << variableBits >>> 0; // >>> 0 coerces to unsigned
+  const numAddresses = Math.pow(2, variableBits);
   return {
     from: new Ipv4Address(fromAddress).toString(),
     to: new Ipv4Address(fromAddress + numAddresses - 1).toString()
diff --git a/src/ui/public/utils/diff_object.js b/src/ui/public/utils/diff_object.js
index 25df114df3729..958bdea9b861d 100644
--- a/src/ui/public/utils/diff_object.js
+++ b/src/ui/public/utils/diff_object.js
@@ -3,14 +3,14 @@ import angular from 'angular';
 
 export default function (target, source) {
 
-  let diff = {};
+  const diff = {};
 
   /**
    * Filter the private vars
    * @param {string} key The keys
    * @returns {boolean}
    */
-  let filterPrivateAndMethods = function (obj) {
+  const filterPrivateAndMethods = function (obj) {
     return function (key) {
       if (_.isFunction(obj[key])) return false;
       if (key.charAt(0) === '$') return false;
@@ -18,8 +18,8 @@ export default function (target, source) {
     };
   };
 
-  let targetKeys = _.keys(target).filter(filterPrivateAndMethods(target));
-  let sourceKeys = _.keys(source).filter(filterPrivateAndMethods(source));
+  const targetKeys = _.keys(target).filter(filterPrivateAndMethods(target));
+  const sourceKeys = _.keys(source).filter(filterPrivateAndMethods(source));
 
   // Find the keys to be removed
   diff.removed = _.difference(targetKeys, sourceKeys);
diff --git a/src/ui/public/utils/diff_time_picker_vals.js b/src/ui/public/utils/diff_time_picker_vals.js
index 43fcfcd5d38d6..093bd8c794f1f 100644
--- a/src/ui/public/utils/diff_time_picker_vals.js
+++ b/src/ui/public/utils/diff_time_picker_vals.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import angular from 'angular';
 export default function DiffTimePickerValuesFn() {
 
-  let valueOf = function (o) {
+  const valueOf = function (o) {
     if (o) return o.valueOf();
   };
 
diff --git a/src/ui/public/utils/es_bool.js b/src/ui/public/utils/es_bool.js
index a580ffac72188..da00487210665 100644
--- a/src/ui/public/utils/es_bool.js
+++ b/src/ui/public/utils/es_bool.js
@@ -1,5 +1,5 @@
 define(function () {
-  let map = {
+  const map = {
     'false': false,
     'off': false,
     'no': false,
@@ -11,7 +11,7 @@ define(function () {
   };
 
   return function (str) {
-    let bool = map[String(str)];
+    const bool = map[String(str)];
 
     if (typeof bool !== 'boolean') {
       throw new TypeError('"' + str + '" does not map to an esBool');
diff --git a/src/ui/public/utils/find_by_param.js b/src/ui/public/utils/find_by_param.js
index 60763f07f8478..507567562937a 100644
--- a/src/ui/public/utils/find_by_param.js
+++ b/src/ui/public/utils/find_by_param.js
@@ -3,7 +3,7 @@ import _ from 'lodash';
 // if the param is missing, return undefined
 export default function findByParam(values, param) {
   if (_.isArray(values)) { // point series chart
-    let index = _.findIndex(values, param);
+    const index = _.findIndex(values, param);
     if (index === -1) return;
     return values[index][param];
   }
diff --git a/src/ui/public/utils/ipv4_address.js b/src/ui/public/utils/ipv4_address.js
index d8c396d02ab6b..6c80920df64ab 100644
--- a/src/ui/public/utils/ipv4_address.js
+++ b/src/ui/public/utils/ipv4_address.js
@@ -1,6 +1,6 @@
 define(function () {
-  let NUM_BYTES = 4;
-  let BYTE_SIZE = 256;
+  const NUM_BYTES = 4;
+  const BYTE_SIZE = 256;
 
   function throwError(ipAddress) {
     throw Error('Invalid IPv4 address: ' + ipAddress);
@@ -19,11 +19,11 @@ define(function () {
     if (typeof ipAddress === 'string') {
       this.value = 0;
 
-      let bytes = ipAddress.split('.');
+      const bytes = ipAddress.split('.');
       if (bytes.length !== NUM_BYTES) throwError(ipAddress);
 
       for (let i = 0; i < bytes.length; i++) {
-        let byte = Number(bytes[i]);
+        const byte = Number(bytes[i]);
         if (!isIntegerInRange(byte, 0, BYTE_SIZE)) throwError(ipAddress);
         this.value += Math.pow(BYTE_SIZE, NUM_BYTES - 1 - i) * byte;
       }
@@ -34,7 +34,7 @@ define(function () {
 
   Ipv4Address.prototype.toString = function () {
     let value = this.value;
-    let bytes = [];
+    const bytes = [];
     for (let i = 0; i < NUM_BYTES; i++) {
       bytes.unshift(value % 256);
       value = Math.floor(value / 256);
diff --git a/src/ui/public/utils/mapping_setup.js b/src/ui/public/utils/mapping_setup.js
index 232fa5ff21072..b1bd1805b85fc 100644
--- a/src/ui/public/utils/mapping_setup.js
+++ b/src/ui/public/utils/mapping_setup.js
@@ -2,9 +2,9 @@ import angular from 'angular';
 import _ from 'lodash';
 define(function () {
   return function MappingSetupService(kbnIndex, es) {
-    let mappingSetup = this;
+    const mappingSetup = this;
 
-    let json = {
+    const json = {
       _serialize: function (val) {
         if (val != null) return angular.toJson(val);
       },
@@ -16,14 +16,14 @@ define(function () {
     /**
      * Use to create the mappings, but that should only happen one at a time
      */
-    let activeTypeCreations = {};
+    const activeTypeCreations = {};
 
     /**
      * Get the list of type's mapped in elasticsearch
      * @return {[type]} [description]
      */
-    let getKnownKibanaTypes = _.once(function () {
-      let indexName = kbnIndex;
+    const getKnownKibanaTypes = _.once(function () {
+      const indexName = kbnIndex;
       return es.indices.getFieldMapping({
         // only concerned with types in this kibana index
         index: indexName,
@@ -70,13 +70,13 @@ define(function () {
         });
       }
 
-      let prom = getKnownKibanaTypes()
+      const prom = getKnownKibanaTypes()
       .then(function (knownTypes) {
         // if the type is in the knownTypes array already
         if (~knownTypes.indexOf(type)) return false;
 
         // we need to create the mapping
-        let body = {};
+        const body = {};
         body[type] = {
           properties: mapping
         };
diff --git a/src/ui/public/utils/no_white_space.js b/src/ui/public/utils/no_white_space.js
index c57cc58fcb95d..6953a044a2374 100644
--- a/src/ui/public/utils/no_white_space.js
+++ b/src/ui/public/utils/no_white_space.js
@@ -1,4 +1,4 @@
-let TAGS_WITH_WS = />\s+</g;
+const TAGS_WITH_WS = />\s+</g;
 
 /**
  * Remove all of the whitespace between html tags
diff --git a/src/ui/public/utils/obj_define.js b/src/ui/public/utils/obj_define.js
index 664c6fcfb2168..9e841055f99c8 100644
--- a/src/ui/public/utils/obj_define.js
+++ b/src/ui/public/utils/obj_define.js
@@ -9,7 +9,7 @@ function ObjDefine(defaults, prototype) {
 }
 
 ObjDefine.REDEFINE_SUPPORTED = (function () {
-  let a = Object.create(Object.prototype, {
+  const a = Object.create(Object.prototype, {
     prop: {
       configurable: true,
       value: 1
@@ -66,7 +66,7 @@ ObjDefine.prototype.comp = function (name, val) {
  * @return {object} - created object
  */
 ObjDefine.prototype.create = function () {
-  let self = this;
+  const self = this;
   self.obj = Object.create(this.prototype, self.descs);
 
   if (!ObjDefine.REDEFINE_SUPPORTED && !self.prototype.toJSON) {
@@ -76,7 +76,7 @@ ObjDefine.prototype.create = function () {
     // due to https://github.com/ariya/phantomjs/issues/11856
     self.obj.toJSON = function () {
       return _.transform(self.obj, function (json, val, key) {
-        let desc = self.descs[key];
+        const desc = self.descs[key];
         if (desc && desc.enumerable && val == null) return;
         json[key] = val;
       }, {});
@@ -97,8 +97,8 @@ ObjDefine.prototype._define = function (name, val, exported, changeable) {
 };
 
 ObjDefine.prototype._describe = function (name, val, exported, changeable) {
-  let self = this;
-  let exists = val != null;
+  const self = this;
+  const exists = val != null;
 
   if (exported && ObjDefine.REDEFINE_SUPPORTED) {
     return {
diff --git a/src/ui/public/utils/ordinal_suffix.js b/src/ui/public/utils/ordinal_suffix.js
index 54038effa2bd9..cfddf1eeee3f9 100644
--- a/src/ui/public/utils/ordinal_suffix.js
+++ b/src/ui/public/utils/ordinal_suffix.js
@@ -5,12 +5,12 @@ export default function addOrdinalSuffix(num) {
 };
 
 function suffix(num) {
-  let int = Math.floor(parseFloat(num));
+  const int = Math.floor(parseFloat(num));
 
-  let hunth = int % 100;
+  const hunth = int % 100;
   if (hunth >= 11 && hunth <= 13) return 'th';
 
-  let tenth = int % 10;
+  const tenth = int % 10;
   if (tenth === 1) return 'st';
   if (tenth === 2) return 'nd';
   if (tenth === 3) return 'rd';
diff --git a/src/ui/public/utils/parse_interval.js b/src/ui/public/utils/parse_interval.js
index 6054c68f8d800..cb5fb6bb1f8ca 100644
--- a/src/ui/public/utils/parse_interval.js
+++ b/src/ui/public/utils/parse_interval.js
@@ -3,18 +3,18 @@ import moment from 'moment';
 import dateMath from '@elastic/datemath';
 
 // Assume interval is in the form (value)(unit), such as "1h"
-let INTERVAL_STRING_RE = new RegExp('^([0-9\\.]*)\\s*(' + dateMath.units.join('|') + ')$');
+const INTERVAL_STRING_RE = new RegExp('^([0-9\\.]*)\\s*(' + dateMath.units.join('|') + ')$');
 
 export default function parseInterval(interval) {
-  let matches = String(interval).trim().match(INTERVAL_STRING_RE);
+  const matches = String(interval).trim().match(INTERVAL_STRING_RE);
 
   if (!matches) return null;
 
   try {
-    let value = parseFloat(matches[1]) || 1;
-    let unit = matches[2];
+    const value = parseFloat(matches[1]) || 1;
+    const unit = matches[2];
 
-    let duration = moment.duration(value, unit);
+    const duration = moment.duration(value, unit);
 
     // There is an error with moment, where if you have a fractional interval between 0 and 1, then when you add that
     // interval to an existing moment object, it will remain unchanged, which causes problems in the ordered_x_keys
@@ -23,7 +23,7 @@ export default function parseInterval(interval) {
     // adding 0.5 days until we hit the end date. However, since there is a bug in moment, when you add 0.5 days to
     // the start date, you get the same exact date (instead of being ahead by 12 hours). So instead of returning
     // a duration corresponding to 0.5 hours, we return a duration corresponding to 12 hours.
-    let selectedUnit = _.find(dateMath.units, function (unit) {
+    const selectedUnit = _.find(dateMath.units, function (unit) {
       return Math.abs(duration.as(unit)) >= 1;
     });
 
diff --git a/src/ui/public/utils/query_string.js b/src/ui/public/utils/query_string.js
index adf714cd64030..c45be4b3f25f1 100644
--- a/src/ui/public/utils/query_string.js
+++ b/src/ui/public/utils/query_string.js
@@ -1,4 +1,4 @@
-let qs = {};
+const qs = {};
 
 /*****
 /*** orignally copied from angular, modified our purposes
@@ -37,7 +37,7 @@ function encodeUriQuery(val, pctEncodeSpaces) {
  * @returns {Object.<string,boolean|Array>}
  */
 qs.decode = function (keyValue) {
-  let obj = {};
+  const obj = {};
   let keyValueParts;
   let key;
 
@@ -46,7 +46,7 @@ qs.decode = function (keyValue) {
       keyValueParts = keyValue.split('=');
       key = tryDecodeURIComponent(keyValueParts[0]);
       if (key !== void 0) {
-        let val = keyValueParts[1] !== void 0 ? tryDecodeURIComponent(keyValueParts[1]) : true;
+        const val = keyValueParts[1] !== void 0 ? tryDecodeURIComponent(keyValueParts[1]) : true;
         if (!obj[key]) {
           obj[key] = val;
         } else if (Array.isArray(obj[key])) {
@@ -66,10 +66,10 @@ qs.decode = function (keyValue) {
  * @return {String}
  */
 qs.encode = function (obj) {
-  let parts = [];
-  let keys = Object.keys(obj).sort();
+  const parts = [];
+  const keys = Object.keys(obj).sort();
   keys.forEach(function (key) {
-    let value = obj[key];
+    const value = obj[key];
     if (Array.isArray(value)) {
       value.forEach(function (arrayValue) {
         parts.push(qs.param(key, arrayValue));
@@ -111,8 +111,8 @@ qs.findInUrl = function (url) {
 };
 
 qs.replaceParamInUrl = function (url, param, newVal) {
-  let loc = qs.findInUrl(url);
-  let parsed = qs.decode(url.substring(loc.start + 1, loc.end));
+  const loc = qs.findInUrl(url);
+  const parsed = qs.decode(url.substring(loc.start + 1, loc.end));
 
   if (newVal != null) {
     parsed[param] = newVal;
@@ -120,7 +120,7 @@ qs.replaceParamInUrl = function (url, param, newVal) {
     delete parsed[param];
   }
 
-  let chars = url.split('');
+  const chars = url.split('');
   chars.splice(loc.start, loc.end - loc.start, '?' + qs.encode(parsed));
   return chars.join('');
 };
diff --git a/src/ui/public/utils/range.js b/src/ui/public/utils/range.js
index dc34e4ab650e0..af9fb1f5a9644 100644
--- a/src/ui/public/utils/range.js
+++ b/src/ui/public/utils/range.js
@@ -13,7 +13,7 @@ import _ from 'lodash';
  *
  * @type {String}
  */
-let _RE_NUMBER = '(\\-?(?:\\d+(?:\\.\\d+)?|Infinity))';
+const _RE_NUMBER = '(\\-?(?:\\d+(?:\\.\\d+)?|Infinity))';
 
 /**
  * Regexp for the interval notation
@@ -25,11 +25,11 @@ let _RE_NUMBER = '(\\-?(?:\\d+(?:\\.\\d+)?|Infinity))';
  *
  * @type {RegExp}
  */
-let RANGE_RE = new RegExp('^\\s*([\\[|\\(])\\s*' + _RE_NUMBER + '\\s*,\\s*' + _RE_NUMBER + '\\s*([\\]|\\)])\\s*$');
+const RANGE_RE = new RegExp('^\\s*([\\[|\\(])\\s*' + _RE_NUMBER + '\\s*,\\s*' + _RE_NUMBER + '\\s*([\\]|\\)])\\s*$');
 
 function parse(input) {
 
-  let match = String(input).match(RANGE_RE);
+  const match = String(input).match(RANGE_RE);
   if (!match) {
     throw new TypeError('expected input to be in interval notation eg. (100, 200]');
   }
@@ -43,7 +43,7 @@ function parse(input) {
 }
 
 function Range(/* minIncl, min, max, maxIncl */) {
-  let args = _.toArray(arguments);
+  const args = _.toArray(arguments);
   if (args[1] > args[2]) args.reverse();
 
   this.minInclusive = args[0];
diff --git a/src/ui/public/utils/scanner.js b/src/ui/public/utils/scanner.js
index 93ddc988d66a2..e43b0e3c45583 100644
--- a/src/ui/public/utils/scanner.js
+++ b/src/ui/public/utils/scanner.js
@@ -1,6 +1,6 @@
 import _ from 'lodash';
 
-let Scanner = function (client, {index, type} = {}) {
+const Scanner = function (client, {index, type} = {}) {
   if (!index) throw new Error('Expected index');
   if (!type) throw new Error('Expected type');
   if (!client) throw new Error('Expected client');
@@ -13,7 +13,7 @@ let Scanner = function (client, {index, type} = {}) {
 Scanner.prototype.scanAndMap = function (searchString, options, mapFn) {
   let scrollId;
   let body;
-  let allResults = {
+  const allResults = {
     hits: [],
     total: 0
   };
diff --git a/src/ui/public/utils/sequencer.js b/src/ui/public/utils/sequencer.js
index 5656890c8f101..5783d1dcb9c08 100644
--- a/src/ui/public/utils/sequencer.js
+++ b/src/ui/public/utils/sequencer.js
@@ -1,18 +1,18 @@
 import _ from 'lodash';
 
 function create(min, max, length, mod) {
-  let seq = new Array(length);
+  const seq = new Array(length);
 
-  let valueDist = max - min;
+  const valueDist = max - min;
 
   // range of values that the mod creates
-  let modRange = [mod(0, length), mod(length - 1, length)];
+  const modRange = [mod(0, length), mod(length - 1, length)];
 
   // distance between
-  let modRangeDist = modRange[1] - modRange[0];
+  const modRangeDist = modRange[1] - modRange[0];
 
   _.times(length, function (i) {
-    let modIPercent = (mod(i, length) - modRange[0]) / modRangeDist;
+    const modIPercent = (mod(i, length) - modRange[0]) / modRangeDist;
 
     // percent applied to distance and added to min to
     // produce value
@@ -80,8 +80,8 @@ export default {
     // adapted from output of http://www.timotheegroleau.com/Flash/experiments/easing_function_generator.htm
     // generates numbers from 0 to 100
 
-    let ts = (i /= length) * i;
-    let tc = ts * i;
+    const ts = (i /= length) * i;
+    const tc = ts * i;
     return 100 * (
       0.5 * tc * ts +
       -3 * ts * ts +
diff --git a/src/ui/public/utils/simple_emitter.js b/src/ui/public/utils/simple_emitter.js
index f9a6f69a24eee..f6a9afbf6a83e 100644
--- a/src/ui/public/utils/simple_emitter.js
+++ b/src/ui/public/utils/simple_emitter.js
@@ -68,7 +68,7 @@ SimpleEmitter.prototype.removeAllListeners = function () {
  */
 SimpleEmitter.prototype.emit = _.restParam(function (name, args) {
   if (!this._listeners[name]) return this;
-  let listeners = this.listeners(name);
+  const listeners = this.listeners(name);
   let i = -1;
 
   while (++i < listeners.length) {
diff --git a/src/ui/public/utils/slugify_id.js b/src/ui/public/utils/slugify_id.js
index 0894d9356593e..64a1b30041f34 100644
--- a/src/ui/public/utils/slugify_id.js
+++ b/src/ui/public/utils/slugify_id.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 export default function (id) {
   if (id == null) return;
 
-  let trans = {
+  const trans = {
     '/' : '-slash-',
     '\\?' : '-questionmark-',
     '\\&' : '-ampersand-',
@@ -10,7 +10,7 @@ export default function (id) {
     '%' : '-percent-'
   };
   _.each(trans, function (val, key) {
-    let regex = new RegExp(key, 'g');
+    const regex = new RegExp(key, 'g');
     id = id.replace(regex, val);
   });
   id = id.replace(/[\s]+/g, '-');
diff --git a/src/ui/public/utils/supports.js b/src/ui/public/utils/supports.js
index cf8cd4835c65f..ec959686fe158 100644
--- a/src/ui/public/utils/supports.js
+++ b/src/ui/public/utils/supports.js
@@ -5,14 +5,14 @@ import _ from 'lodash';
  */
 export default {
   cssFilters: (function () {
-    let e = document.createElement('img');
-    let rules = ['webkitFilter', 'mozFilter', 'msFilter', 'filter'];
-    let test = 'grayscale(1)';
+    const e = document.createElement('img');
+    const rules = ['webkitFilter', 'mozFilter', 'msFilter', 'filter'];
+    const test = 'grayscale(1)';
     rules.forEach(function (rule) { e.style[rule] = test; });
 
     document.body.appendChild(e);
-    let styles = window.getComputedStyle(e);
-    let can = _(styles).pick(rules).includes(test);
+    const styles = window.getComputedStyle(e);
+    const can = _(styles).pick(rules).includes(test);
     document.body.removeChild(e);
 
     return can;
diff --git a/src/ui/public/vis/__tests__/_agg_config.js b/src/ui/public/vis/__tests__/_agg_config.js
index 02502f5a34001..b850bdd092ed6 100644
--- a/src/ui/public/vis/__tests__/_agg_config.js
+++ b/src/ui/public/vis/__tests__/_agg_config.js
@@ -25,7 +25,7 @@ describe('AggConfig', function () {
 
   describe('#toDsl', function () {
     it('calls #write()', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -35,15 +35,15 @@ describe('AggConfig', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.date_histogram[0];
-      let stub = sinon.stub(aggConfig, 'write').returns({ params: {} });
+      const aggConfig = vis.aggs.byTypeName.date_histogram[0];
+      const stub = sinon.stub(aggConfig, 'write').returns({ params: {} });
 
       aggConfig.toDsl();
       expect(stub.callCount).to.be(1);
     });
 
     it('uses the type name as the agg name', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -53,15 +53,15 @@ describe('AggConfig', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.date_histogram[0];
+      const aggConfig = vis.aggs.byTypeName.date_histogram[0];
       sinon.stub(aggConfig, 'write').returns({ params: {} });
 
-      let dsl = aggConfig.toDsl();
+      const dsl = aggConfig.toDsl();
       expect(dsl).to.have.property('date_histogram');
     });
 
     it('uses the params from #write() output as the agg params', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -71,17 +71,17 @@ describe('AggConfig', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.date_histogram[0];
-      let football = {};
+      const aggConfig = vis.aggs.byTypeName.date_histogram[0];
+      const football = {};
 
       sinon.stub(aggConfig, 'write').returns({ params: football });
 
-      let dsl = aggConfig.toDsl();
+      const dsl = aggConfig.toDsl();
       expect(dsl.date_histogram).to.be(football);
     });
 
     it('includes subAggs from #write() output', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -95,14 +95,14 @@ describe('AggConfig', function () {
         ]
       });
 
-      let histoConfig = vis.aggs.byTypeName.date_histogram[0];
-      let avgConfig = vis.aggs.byTypeName.avg[0];
-      let football = {};
+      const histoConfig = vis.aggs.byTypeName.date_histogram[0];
+      const avgConfig = vis.aggs.byTypeName.avg[0];
+      const football = {};
 
       sinon.stub(histoConfig, 'write').returns({ params: {}, subAggs: [avgConfig] });
       sinon.stub(avgConfig, 'write').returns({ params: football });
 
-      let dsl = histoConfig.toDsl();
+      const dsl = histoConfig.toDsl();
 
       // didn't use .eql() because of variable key names, and final check is strict
       expect(dsl).to.have.property('aggs');
@@ -114,7 +114,7 @@ describe('AggConfig', function () {
 
   describe('::ensureIds', function () {
     it('accepts an array of objects and assigns ids to them', function () {
-      let objs = [
+      const objs = [
         {},
         {},
         {},
@@ -128,7 +128,7 @@ describe('AggConfig', function () {
     });
 
     it('assigns ids relative to the other items in the list', function () {
-      let objs = [
+      const objs = [
         { id: '100' },
         {},
       ];
@@ -138,7 +138,7 @@ describe('AggConfig', function () {
     });
 
     it('assigns ids relative to the other items in the list', function () {
-      let objs = [
+      const objs = [
         { id: '100' },
         { id: '200' },
         { id: '500' },
@@ -155,14 +155,14 @@ describe('AggConfig', function () {
 
     it('uses ::nextId to get the starting value', function () {
       sinon.stub(AggConfig, 'nextId').returns(534);
-      let objs = AggConfig.ensureIds([{}]);
+      const objs = AggConfig.ensureIds([{}]);
       expect(objs[0]).to.have.property('id', '534');
     });
 
     it('only calls ::nextId once', function () {
-      let start = 420;
+      const start = 420;
       sinon.stub(AggConfig, 'nextId').returns(start);
-      let objs = AggConfig.ensureIds([{}, {}, {}, {}, {}, {}, {}]);
+      const objs = AggConfig.ensureIds([{}, {}, {}, {}, {}, {}, {}]);
 
       expect(AggConfig.nextId).to.have.property('callCount', 1);
       objs.forEach(function (obj, i) {
@@ -173,12 +173,12 @@ describe('AggConfig', function () {
 
   describe('::nextId', function () {
     it('accepts a list of objects and picks the next id', function () {
-      let next = AggConfig.nextId([ {id: 100}, {id: 500} ]);
+      const next = AggConfig.nextId([ {id: 100}, {id: 500} ]);
       expect(next).to.be(501);
     });
 
     it('handles an empty list', function () {
-      let next = AggConfig.nextId([]);
+      const next = AggConfig.nextId([]);
       expect(next).to.be(1);
     });
 
@@ -328,7 +328,7 @@ describe('AggConfig', function () {
 
   describe('#toJSON', function () {
     it('includes the aggs id, params, type and schema', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -338,13 +338,13 @@ describe('AggConfig', function () {
         ]
       });
 
-      let aggConfig = vis.aggs.byTypeName.date_histogram[0];
+      const aggConfig = vis.aggs.byTypeName.date_histogram[0];
       expect(aggConfig.id).to.be('1');
       expect(aggConfig.params).to.be.an('object');
       expect(aggConfig.type).to.be.an(AggType).and.have.property('name', 'date_histogram');
       expect(aggConfig.schema).to.be.an('object').and.have.property('name', 'segment');
 
-      let state = aggConfig.toJSON();
+      const state = aggConfig.toJSON();
       expect(state).to.have.property('id', '1');
       expect(state.params).to.be.an('object');
       expect(state).to.have.property('type', 'date_histogram');
@@ -354,7 +354,7 @@ describe('AggConfig', function () {
 
 
     it('test serialization  order is identical (for visual consistency)', function () {
-      let vis1 = new Vis(indexPattern, {
+      const vis1 = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -363,7 +363,7 @@ describe('AggConfig', function () {
           }
         ]
       });
-      let vis2 = new Vis(indexPattern, {
+      const vis2 = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -385,30 +385,30 @@ describe('AggConfig', function () {
 
   describe('#makeLabel', function () {
     it('uses the custom label if it is defined', function () {
-      let vis = new Vis(indexPattern, {});
-      let aggConfig = vis.aggs[0];
+      const vis = new Vis(indexPattern, {});
+      const aggConfig = vis.aggs[0];
       aggConfig.params.customLabel = 'Custom label';
-      let label = aggConfig.makeLabel();
+      const label = aggConfig.makeLabel();
       expect(label).to.be(aggConfig.params.customLabel);
     });
     it('default label should be "Count"', function () {
-      let vis = new Vis(indexPattern, {});
-      let aggConfig = vis.aggs[0];
-      let label = aggConfig.makeLabel();
+      const vis = new Vis(indexPattern, {});
+      const aggConfig = vis.aggs[0];
+      const label = aggConfig.makeLabel();
       expect(label).to.be('Count');
     });
     it('default label should be "Percentage of Count" when Vis is in percentage mode', function () {
-      let vis = new Vis(indexPattern, {});
-      let aggConfig = vis.aggs[0];
+      const vis = new Vis(indexPattern, {});
+      const aggConfig = vis.aggs[0];
       aggConfig.vis.params.mode = 'percentage';
-      let label = aggConfig.makeLabel();
+      const label = aggConfig.makeLabel();
       expect(label).to.be('Percentage of Count');
     });
     it('empty label if the Vis type is not defined', function () {
-      let vis = new Vis(indexPattern, {});
-      let aggConfig = vis.aggs[0];
+      const vis = new Vis(indexPattern, {});
+      const aggConfig = vis.aggs[0];
       aggConfig.type = undefined;
-      let label = aggConfig.makeLabel();
+      const label = aggConfig.makeLabel();
       expect(label).to.be('');
     });
   });
@@ -441,7 +441,7 @@ describe('AggConfig', function () {
     });
 
     it('returns the string format if the field does not have a format', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -452,13 +452,13 @@ describe('AggConfig', function () {
         ]
       });
 
-      let agg = vis.aggs[0];
+      const agg = vis.aggs[0];
       agg.params.field = { type: 'date', format: null };
       expect(agg.fieldFormatter()).to.be(fieldFormat.getDefaultInstance('string').getConverterFor());
     });
 
     it('returns the string format if their is no field', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -469,13 +469,13 @@ describe('AggConfig', function () {
         ]
       });
 
-      let agg = vis.aggs[0];
+      const agg = vis.aggs[0];
       delete agg.params.field;
       expect(agg.fieldFormatter()).to.be(fieldFormat.getDefaultInstance('string').getConverterFor());
     });
 
     it('returns the html converter if "html" is passed in', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           {
@@ -486,7 +486,7 @@ describe('AggConfig', function () {
         ]
       });
 
-      let field = indexPattern.fields.byName.ssl;
+      const field = indexPattern.fields.byName.ssl;
       expect(vis.aggs[0].fieldFormatter('html')).to.be(field.format.getConverterFor('html'));
     });
   });
diff --git a/src/ui/public/vis/__tests__/_agg_config_result.js b/src/ui/public/vis/__tests__/_agg_config_result.js
index 100549de9a924..ba60045425dae 100644
--- a/src/ui/public/vis/__tests__/_agg_config_result.js
+++ b/src/ui/public/vis/__tests__/_agg_config_result.js
@@ -20,12 +20,12 @@ describe('AggConfigResult', function () {
 
   describe('initialization', function () {
     it('should set the type to bucket for bucket based results', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [ { type: 'terms', schema: 'segment', params: { field: '_type' } } ]
       });
-      let aggConfig = vis.aggs.byTypeName.terms[0];
-      let results = new AggConfigResult(aggConfig, null, 10, 'apache');
+      const aggConfig = vis.aggs.byTypeName.terms[0];
+      const results = new AggConfigResult(aggConfig, null, 10, 'apache');
       expect(results).to.have.property('aggConfig', aggConfig);
       expect(results).to.have.property('$parent', null);
       expect(results).to.have.property('type', 'bucket');
@@ -34,12 +34,12 @@ describe('AggConfigResult', function () {
     });
 
     it('should set the type to metric for metric based results', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [ { type: 'avg', schema: 'metric', params: { field: 'bytes' } } ]
       });
-      let aggConfig = vis.aggs.byTypeName.avg[0];
-      let results = new AggConfigResult(aggConfig, null, 1024);
+      const aggConfig = vis.aggs.byTypeName.avg[0];
+      const results = new AggConfigResult(aggConfig, null, 1024);
       expect(results).to.have.property('aggConfig', aggConfig);
       expect(results).to.have.property('$parent', null);
       expect(results).to.have.property('type', 'metric');
@@ -53,18 +53,18 @@ describe('AggConfigResult', function () {
     describe('getPath()', function () {
 
       it('should return the parent and itself (in an array) for the path', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', schema: 'segment', params: { field: '_type' } },
             { type: 'terms', schema: 'segment', params: { field: 'extension' } }
           ]
         });
-        let parentAggConfig = vis.aggs.byTypeName.terms[0];
-        let aggConfig = vis.aggs.byTypeName.terms[1];
-        let parentResult = new AggConfigResult(parentAggConfig, null, 20, 'apache');
-        let result = new AggConfigResult(aggConfig, parentResult, 15, 'php');
-        let path = result.getPath();
+        const parentAggConfig = vis.aggs.byTypeName.terms[0];
+        const aggConfig = vis.aggs.byTypeName.terms[1];
+        const parentResult = new AggConfigResult(parentAggConfig, null, 20, 'apache');
+        const result = new AggConfigResult(aggConfig, parentResult, 15, 'php');
+        const path = result.getPath();
         expect(path).to.be.an(Array);
         expect(path).to.have.length(2);
         expect(path[0]).to.be(parentResult);
@@ -72,15 +72,15 @@ describe('AggConfigResult', function () {
       });
 
       it('should return itself (in an array) for the path', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', schema: 'segment', params: { field: 'extension' } }
           ]
         });
-        let aggConfig = vis.aggs.byTypeName.terms[0];
-        let result = new AggConfigResult(aggConfig, null, 15, 'php');
-        let path = result.getPath();
+        const aggConfig = vis.aggs.byTypeName.terms[0];
+        const result = new AggConfigResult(aggConfig, null, 15, 'php');
+        const path = result.getPath();
         expect(path).to.be.an(Array);
         expect(path).to.have.length(1);
         expect(path[0]).to.be(result);
@@ -90,15 +90,15 @@ describe('AggConfigResult', function () {
 
     describe('createFilter', function () {
       it('should return a filter object that represents the result', function () {
-        let vis = new Vis(indexPattern, {
+        const vis = new Vis(indexPattern, {
           type: 'histogram',
           aggs: [
             { type: 'terms', schema: 'segment', params: { field: 'extension' } }
           ]
         });
-        let aggConfig = vis.aggs.byTypeName.terms[0];
-        let result = new AggConfigResult(aggConfig, null, 15, 'php');
-        let filter = result.createFilter();
+        const aggConfig = vis.aggs.byTypeName.terms[0];
+        const result = new AggConfigResult(aggConfig, null, 15, 'php');
+        const filter = result.createFilter();
         expect(filter).to.have.property('query');
         expect(filter.query).to.have.property('match');
         expect(filter.query.match).to.have.property('extension');
diff --git a/src/ui/public/vis/__tests__/_agg_configs.js b/src/ui/public/vis/__tests__/_agg_configs.js
index b8e4b72dd9d1b..db7df64e19321 100644
--- a/src/ui/public/vis/__tests__/_agg_configs.js
+++ b/src/ui/public/vis/__tests__/_agg_configs.js
@@ -22,7 +22,7 @@ describe('AggConfigs', function () {
   beforeEach(ngMock.inject(function (Private) {
     // replace the AggConfig module with a spy
     AggConfig = Private(RealAggConfigPM);
-    let spy = sinon.spy(AggConfig);
+    const spy = sinon.spy(AggConfig);
     Object.defineProperty(spy, 'aggTypes', {
       get: function () { return AggConfig.aggTypes; },
       set: function (val) { AggConfig.aggTypes = val; }
@@ -40,28 +40,28 @@ describe('AggConfigs', function () {
   }));
 
   it('extends IndexedArray', function () {
-    let ac = new AggConfigs();
+    const ac = new AggConfigs();
     expect(ac).to.be.a(IndexedArray);
   });
 
   describe('constructor', function () {
     it('handles passing just a vis', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: []
       });
 
-      let ac = new AggConfigs(vis);
+      const ac = new AggConfigs(vis);
       expect(ac).to.have.length(1);
     });
 
     it('converts configStates into AggConfig objects if they are not already', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: []
       });
 
-      let ac = new AggConfigs(vis, [
+      const ac = new AggConfigs(vis, [
         {
           type: 'date_histogram',
           schema: 'segment'
@@ -77,12 +77,12 @@ describe('AggConfigs', function () {
     });
 
     it('attemps to ensure that all states have an id', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: []
       });
 
-      let states = [
+      const states = [
         {
           type: 'date_histogram',
           schema: 'segment'
@@ -93,8 +93,8 @@ describe('AggConfigs', function () {
         }
       ];
 
-      let spy = sinon.spy(SpiedAggConfig, 'ensureIds');
-      let ac = new AggConfigs(vis, states);
+      const spy = sinon.spy(SpiedAggConfig, 'ensureIds');
+      const ac = new AggConfigs(vis, states);
       expect(spy.callCount).to.be(1);
       expect(spy.firstCall.args[0]).to.be(states);
     });
@@ -135,17 +135,17 @@ describe('AggConfigs', function () {
       });
 
       it('should only set the number of defaults defined by the max', function () {
-        let ac = new AggConfigs(vis);
+        const ac = new AggConfigs(vis);
         expect(ac.bySchemaName.metric).to.have.length(2);
       });
 
       it('should set the defaults defined in the schema when none exist', function () {
-        let ac = new AggConfigs(vis);
+        const ac = new AggConfigs(vis);
         expect(ac).to.have.length(3);
       });
 
       it('should NOT set the defaults defined in the schema when some exist', function () {
-        let ac = new AggConfigs(vis, [{ schema: 'segment', type: 'date_histogram' }]);
+        const ac = new AggConfigs(vis, [{ schema: 'segment', type: 'date_histogram' }]);
         expect(ac).to.have.length(3);
         expect(ac.bySchemaName.segment[0].type.name).to.equal('date_histogram');
       });
@@ -154,7 +154,7 @@ describe('AggConfigs', function () {
 
   describe('#getRequestAggs', function () {
     it('performs a stable sort, but moves metrics to the bottom', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           { type: 'avg', schema: 'metric' },
@@ -167,8 +167,8 @@ describe('AggConfigs', function () {
         ]
       });
 
-      let sorted = vis.aggs.getRequestAggs();
-      let aggs = _.indexBy(vis.aggs, function (agg) {
+      const sorted = vis.aggs.getRequestAggs();
+      const aggs = _.indexBy(vis.aggs, function (agg) {
         return agg.type.name;
       });
 
@@ -185,7 +185,7 @@ describe('AggConfigs', function () {
 
   describe('#getResponseAggs', function () {
     it('returns all request aggs for basic aggs', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           { type: 'terms', schema: 'split' },
@@ -194,8 +194,8 @@ describe('AggConfigs', function () {
         ]
       });
 
-      let sorted = vis.aggs.getResponseAggs();
-      let aggs = _.indexBy(vis.aggs, function (agg) {
+      const sorted = vis.aggs.getResponseAggs();
+      const aggs = _.indexBy(vis.aggs, function (agg) {
         return agg.type.name;
       });
 
@@ -206,7 +206,7 @@ describe('AggConfigs', function () {
     });
 
     it('expands aggs that have multiple responses', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           { type: 'terms', schema: 'split' },
@@ -215,8 +215,8 @@ describe('AggConfigs', function () {
         ]
       });
 
-      let sorted = vis.aggs.getResponseAggs();
-      let aggs = _.indexBy(vis.aggs, function (agg) {
+      const sorted = vis.aggs.getResponseAggs();
+      const aggs = _.indexBy(vis.aggs, function (agg) {
         return agg.type.name;
       });
 
@@ -231,14 +231,14 @@ describe('AggConfigs', function () {
 
   describe('#toDsl', function () {
     it('uses the sorted aggs', function () {
-      let vis = new Vis(indexPattern, { type: 'histogram' });
+      const vis = new Vis(indexPattern, { type: 'histogram' });
       sinon.spy(vis.aggs, 'getRequestAggs');
       vis.aggs.toDsl();
       expect(vis.aggs.getRequestAggs).to.have.property('callCount', 1);
     });
 
     it('calls aggConfig#toDsl() on each aggConfig and compiles the nested output', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           { type: 'date_histogram', schema: 'segment' },
@@ -246,8 +246,8 @@ describe('AggConfigs', function () {
         ]
       });
 
-      let aggInfos = vis.aggs.map(function (aggConfig) {
-        let football = {};
+      const aggInfos = vis.aggs.map(function (aggConfig) {
+        const football = {};
 
         sinon.stub(aggConfig, 'toDsl', function () {
           return football;
@@ -260,7 +260,7 @@ describe('AggConfigs', function () {
       });
 
       (function recurse(lvl) {
-        let info = aggInfos.shift();
+        const info = aggInfos.shift();
 
         expect(lvl).to.have.property(info.id);
         expect(lvl[info.id]).to.be(info.football);
@@ -274,7 +274,7 @@ describe('AggConfigs', function () {
     });
 
     it('skips aggs that don\'t have a dsl representation', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           { type: 'date_histogram', schema: 'segment', params: { field: '@timestamp' } },
@@ -282,9 +282,9 @@ describe('AggConfigs', function () {
         ]
       });
 
-      let dsl = vis.aggs.toDsl();
-      let histo = vis.aggs.byTypeName.date_histogram[0];
-      let count = vis.aggs.byTypeName.count[0];
+      const dsl = vis.aggs.toDsl();
+      const histo = vis.aggs.byTypeName.date_histogram[0];
+      const count = vis.aggs.byTypeName.count[0];
 
       expect(dsl).to.have.property(histo.id);
       expect(dsl[histo.id]).to.be.an('object');
@@ -293,7 +293,7 @@ describe('AggConfigs', function () {
     });
 
     it('writes multiple metric aggregations at the same level', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           { type: 'date_histogram', schema: 'segment', params: { field: '@timestamp' } },
@@ -304,10 +304,10 @@ describe('AggConfigs', function () {
         ]
       });
 
-      let dsl = vis.aggs.toDsl();
+      const dsl = vis.aggs.toDsl();
 
-      let histo = vis.aggs.byTypeName.date_histogram[0];
-      let metrics = vis.aggs.bySchemaGroup.metrics;
+      const histo = vis.aggs.byTypeName.date_histogram[0];
+      const metrics = vis.aggs.bySchemaGroup.metrics;
 
       expect(dsl).to.have.property(histo.id);
       expect(dsl[histo.id]).to.be.an('object');
@@ -320,7 +320,7 @@ describe('AggConfigs', function () {
     });
 
     it('writes multiple metric aggregations at every level if the vis is hierarchical', function () {
-      let vis = new Vis(indexPattern, {
+      const vis = new Vis(indexPattern, {
         type: 'histogram',
         aggs: [
           { type: 'terms', schema: 'segment', params: { field: 'ip', orderBy: 1 } },
@@ -333,12 +333,12 @@ describe('AggConfigs', function () {
       });
       vis.isHierarchical = _.constant(true);
 
-      let topLevelDsl = vis.aggs.toDsl();
-      let buckets = vis.aggs.bySchemaGroup.buckets;
-      let metrics = vis.aggs.bySchemaGroup.metrics;
+      const topLevelDsl = vis.aggs.toDsl();
+      const buckets = vis.aggs.bySchemaGroup.buckets;
+      const metrics = vis.aggs.bySchemaGroup.metrics;
 
       (function checkLevel(dsl) {
-        let bucket = buckets.shift();
+        const bucket = buckets.shift();
         expect(dsl).to.have.property(bucket.id);
 
         expect(dsl[bucket.id]).to.be.an('object');
diff --git a/src/ui/public/vis/__tests__/_vis.js b/src/ui/public/vis/__tests__/_vis.js
index ad4aa0ad837e5..fa009472023ea 100644
--- a/src/ui/public/vis/__tests__/_vis.js
+++ b/src/ui/public/vis/__tests__/_vis.js
@@ -12,7 +12,7 @@ describe('Vis Class', function () {
   let visTypes;
 
   let vis;
-  let stateFixture = {
+  const stateFixture = {
     type: 'pie',
     aggs: [
       { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
@@ -34,7 +34,7 @@ describe('Vis Class', function () {
     vis = new Vis(indexPattern, stateFixture);
   });
 
-  let verifyVis = function (vis) {
+  const verifyVis = function (vis) {
     expect(vis).to.have.property('aggs');
     expect(vis.aggs).to.have.length(3);
 
@@ -58,7 +58,7 @@ describe('Vis Class', function () {
 
   describe('getState()', function () {
     it('should get a state that represents the... er... state', function () {
-      let state = vis.getEnabledState();
+      const state = vis.getEnabledState();
       expect(state).to.have.property('type', 'pie');
 
       expect(state).to.have.property('params');
@@ -75,14 +75,14 @@ describe('Vis Class', function () {
 
   describe('clone()', function () {
     it('should make clone of itself', function () {
-      let clone = vis.clone();
+      const clone = vis.clone();
       verifyVis(clone);
     });
   });
 
   describe('setState()', function () {
     it('should set the state to defualts', function () {
-      let vis = new Vis(indexPattern);
+      const vis = new Vis(indexPattern);
       expect(vis).to.have.property('type');
       expect(vis.type).to.eql(visTypes.byName.histogram);
       expect(vis).to.have.property('aggs');
@@ -102,7 +102,7 @@ describe('Vis Class', function () {
       expect(vis.isHierarchical()).to.be(true);
     });
     it('should return false for non-hierarchical vis (like histogram)', function () {
-      let vis = new Vis(indexPattern);
+      const vis = new Vis(indexPattern);
       expect(vis.isHierarchical()).to.be(false);
     });
   });
diff --git a/src/ui/public/vis/agg_config.js b/src/ui/public/vis/agg_config.js
index c1250db719b98..d17b471d2a248 100644
--- a/src/ui/public/vis/agg_config.js
+++ b/src/ui/public/vis/agg_config.js
@@ -1,10 +1,10 @@
 import _ from 'lodash';
 import RegistryFieldFormatsProvider from 'ui/registry/field_formats';
 export default function AggConfigFactory(Private, fieldTypeFilter) {
-  let fieldFormats = Private(RegistryFieldFormatsProvider);
+  const fieldFormats = Private(RegistryFieldFormatsProvider);
 
   function AggConfig(vis, opts) {
-    let self = this;
+    const self = this;
 
     self.id = String(opts.id || AggConfig.nextId(vis.aggs));
     self.vis = vis;
@@ -27,8 +27,8 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {array} - the list that was passed in
    */
   AggConfig.ensureIds = function (list) {
-    let have = [];
-    let haveNot = [];
+    const have = [];
+    const haveNot = [];
     list.forEach(function (obj) {
       (obj.id ? have : haveNot).push(obj);
     });
@@ -98,9 +98,9 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {undefined}
    */
   AggConfig.prototype.fillDefaults = function (from) {
-    let self = this;
+    const self = this;
     from = from || self.params || {};
-    let to = self.params = {};
+    const to = self.params = {};
 
     self.getAggParams().forEach(function (aggParam) {
       let val = from[aggParam.name];
@@ -117,11 +117,11 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
       }
 
       if (aggParam.deserialize) {
-        let isTyped = _.isFunction(aggParam.type);
+        const isTyped = _.isFunction(aggParam.type);
 
-        let isType = isTyped && (val instanceof aggParam.type);
-        let isObject = !isTyped && _.isObject(val);
-        let isDeserialized = (isType || isObject);
+        const isType = isTyped && (val instanceof aggParam.type);
+        const isObject = !isTyped && _.isObject(val);
+        const isDeserialized = (isType || isObject);
 
         if (!isDeserialized) {
           val = aggParam.deserialize(val, self);
@@ -141,12 +141,12 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {object} the new params object
    */
   AggConfig.prototype.resetParams = function () {
-    let fieldParam = this.type && this.type.params.byName.field;
+    const fieldParam = this.type && this.type.params.byName.field;
     let field;
 
     if (fieldParam) {
-      let prevField = this.params.field;
-      let fieldOpts = fieldTypeFilter(this.vis.indexPattern.fields, fieldParam.filterFieldTypes);
+      const prevField = this.params.field;
+      const fieldOpts = fieldTypeFilter(this.vis.indexPattern.fields, fieldParam.filterFieldTypes);
       field = _.contains(fieldOpts, prevField) ? prevField : null;
     }
 
@@ -162,8 +162,8 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
       throw new TypeError('The "' + this.type.title + '" aggregation does not support filtering.');
     }
 
-    let field = this.field();
-    let label = this.fieldDisplayName();
+    const field = this.field();
+    const label = this.fieldDisplayName();
     if (field && !field.filterable) {
       let message = 'The "' + label + '" field can not be used for filtering.';
       if (field.scripted) {
@@ -182,7 +182,7 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    * @return {[type]} [description]
    */
   AggConfig.prototype.requesting = function () {
-    let self = this;
+    const self = this;
     self.type && self.type.params.forEach(function (param) {
       if (param.onRequest) param.onRequest(self);
     });
@@ -199,14 +199,14 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
    */
   AggConfig.prototype.toDsl = function () {
     if (this.type.hasNoDsl) return;
-    let output = this.write();
+    const output = this.write();
 
-    let configDsl = {};
+    const configDsl = {};
     configDsl[this.type.dslName || this.type.name] = output.params;
 
     // if the config requires subAggs, write them to the dsl as well
     if (output.subAggs) {
-      let subDslLvl = configDsl.aggs || (configDsl.aggs = {});
+      const subDslLvl = configDsl.aggs || (configDsl.aggs = {});
       output.subAggs.forEach(function nestAdhocSubAggs(subAggConfig) {
         subDslLvl[subAggConfig.id] = subAggConfig.toDsl();
       });
@@ -216,10 +216,10 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
   };
 
   AggConfig.prototype.toJSON = function () {
-    let self = this;
-    let params = self.params;
+    const self = this;
+    const params = self.params;
 
-    let outParams = _.transform(self.getAggParams(), function (out, aggParam) {
+    const outParams = _.transform(self.getAggParams(), function (out, aggParam) {
       let val = params[aggParam.name];
 
       // don't serialize undefined/null values
@@ -275,13 +275,13 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
   };
 
   AggConfig.prototype.fieldFormatter = function (contentType, defaultFormat) {
-    let format = this.type && this.type.getFormat(this);
+    const format = this.type && this.type.getFormat(this);
     if (format) return format.getConverterFor(contentType);
     return this.fieldOwnFormatter(contentType, defaultFormat);
   };
 
   AggConfig.prototype.fieldOwnFormatter = function (contentType, defaultFormat) {
-    let field = this.field();
+    const field = this.field();
     let format = field && field.format;
     if (!format) format = defaultFormat;
     if (!format) format = fieldFormats.getDefaultInstance('string');
@@ -289,17 +289,17 @@ export default function AggConfigFactory(Private, fieldTypeFilter) {
   };
 
   AggConfig.prototype.fieldName = function () {
-    let field = this.field();
+    const field = this.field();
     return field ? field.name : '';
   };
 
   AggConfig.prototype.fieldDisplayName = function () {
-    let field = this.field();
+    const field = this.field();
     return field ? (field.displayName || this.fieldName()) : '';
   };
 
   AggConfig.prototype.fieldIsTimeField = function () {
-    let timeFieldName = this.vis.indexPattern.timeFieldName;
+    const timeFieldName = this.vis.indexPattern.timeFieldName;
     return timeFieldName && this.fieldName() === timeFieldName;
   };
 
diff --git a/src/ui/public/vis/agg_configs.js b/src/ui/public/vis/agg_configs.js
index ccacd7cafaefa..db2de0b8a0ff2 100644
--- a/src/ui/public/vis/agg_configs.js
+++ b/src/ui/public/vis/agg_configs.js
@@ -3,13 +3,13 @@ import IndexedArray from 'ui/indexed_array';
 import VisAggConfigProvider from 'ui/vis/agg_config';
 import AggTypesIndexProvider from 'ui/agg_types/index';
 export default function AggConfigsFactory(Private) {
-  let AggConfig = Private(VisAggConfigProvider);
+  const AggConfig = Private(VisAggConfigProvider);
 
   AggConfig.aggTypes = Private(AggTypesIndexProvider);
 
   _.class(AggConfigs).inherits(IndexedArray);
   function AggConfigs(vis, configStates) {
-    let self = this;
+    const self = this;
     self.vis = vis;
 
     configStates = AggConfig.ensureIds(configStates || []);
@@ -36,9 +36,9 @@ export default function AggConfigsFactory(Private) {
       })
       .each(function (schema) {
         if (!self.bySchemaName[schema.name]) {
-          let defaults = schema.defaults.slice(0, schema.max);
+          const defaults = schema.defaults.slice(0, schema.max);
           _.each(defaults, function (defaultState) {
-            let state = _.defaults({ id: AggConfig.nextId(self) }, defaultState);
+            const state = _.defaults({ id: AggConfig.nextId(self) }, defaultState);
             self.push(new AggConfig(vis, state));
           });
         }
@@ -65,7 +65,7 @@ export default function AggConfigsFactory(Private) {
   };
 
   AggConfigs.prototype.toDsl = function () {
-    let dslTopLvl = {};
+    const dslTopLvl = {};
     let dslLvlCursor;
     let nestedMetrics;
 
@@ -93,8 +93,8 @@ export default function AggConfigsFactory(Private) {
         // start at the top level
         dslLvlCursor = dslTopLvl;
       } else {
-        let prevConfig = list[i - 1];
-        let prevDsl = dslLvlCursor[prevConfig.id];
+        const prevConfig = list[i - 1];
+        const prevDsl = dslLvlCursor[prevConfig.id];
 
         // advance the cursor and nest under the previous agg, or
         // put it on the same level if the previous agg doesn't accept
@@ -102,7 +102,7 @@ export default function AggConfigsFactory(Private) {
         dslLvlCursor = prevDsl.aggs || dslLvlCursor;
       }
 
-      let dsl = dslLvlCursor[config.id] = config.toDsl();
+      const dsl = dslLvlCursor[config.id] = config.toDsl();
       let subAggs;
 
       if (config.schema.group === 'buckets' && i < list.length - 1) {
@@ -139,7 +139,7 @@ export default function AggConfigsFactory(Private) {
    */
   AggConfigs.prototype.getResponseAggs = function () {
     return this.getRequestAggs().reduce(function (responseValuesAggs, agg) {
-      let aggs = agg.getResponseAggs();
+      const aggs = agg.getResponseAggs();
       return aggs ? responseValuesAggs.concat(aggs) : responseValuesAggs;
     }, []);
   };
@@ -154,7 +154,7 @@ export default function AggConfigsFactory(Private) {
    */
   AggConfigs.prototype.getResponseAggById = function (id) {
     id = String(id);
-    let reqAgg = _.find(this.getRequestAggs(), function (agg) {
+    const reqAgg = _.find(this.getRequestAggs(), function (agg) {
       return id.substr(0, String(agg.id).length) === agg.id;
     });
     if (!reqAgg) return;
diff --git a/src/ui/public/vis/schemas.js b/src/ui/public/vis/schemas.js
index f35c1a6d1324d..28587742edb28 100644
--- a/src/ui/public/vis/schemas.js
+++ b/src/ui/public/vis/schemas.js
@@ -2,10 +2,10 @@ import _ from 'lodash';
 import IndexedArray from 'ui/indexed_array';
 import AggTypesAggParamsProvider from 'ui/agg_types/agg_params';
 export default function VisTypeSchemasFactory(Private) {
-  let AggParams = Private(AggTypesAggParamsProvider);
+  const AggParams = Private(AggTypesAggParamsProvider);
 
   function Schemas(schemas) {
-    let self = this;
+    const self = this;
 
     _(schemas || [])
     .map(function (schema) {
diff --git a/src/ui/public/vis/vis.js b/src/ui/public/vis/vis.js
index f350c4bdbfd50..26fdb9d65d51c 100644
--- a/src/ui/public/vis/vis.js
+++ b/src/ui/public/vis/vis.js
@@ -4,12 +4,12 @@ import RegistryVisTypesProvider from 'ui/registry/vis_types';
 import VisAggConfigsProvider from 'ui/vis/agg_configs';
 import PersistedStateProvider from 'ui/persisted_state/persisted_state';
 export default function VisFactory(Notifier, Private) {
-  let aggTypes = Private(AggTypesIndexProvider);
-  let visTypes = Private(RegistryVisTypesProvider);
-  let AggConfigs = Private(VisAggConfigsProvider);
+  const aggTypes = Private(AggTypesIndexProvider);
+  const visTypes = Private(RegistryVisTypesProvider);
+  const AggConfigs = Private(VisAggConfigsProvider);
   const PersistedState = Private(PersistedStateProvider);
 
-  let notify = new Notifier({
+  const notify = new Notifier({
     location: 'Vis'
   });
 
@@ -34,10 +34,10 @@ export default function VisFactory(Notifier, Private) {
       type = visTypes.byName[type || 'histogram'];
     }
 
-    let schemas = type.schemas;
+    const schemas = type.schemas;
 
-    let aggs = _.transform(oldState, function (newConfigs, oldConfigs, oldGroupName) {
-      let schema = schemas.all.byName[oldGroupName];
+    const aggs = _.transform(oldState, function (newConfigs, oldConfigs, oldGroupName) {
+      const schema = schemas.all.byName[oldGroupName];
 
       if (!schema) {
         notify.log('unable to match old schema', oldGroupName, 'to a new schema');
@@ -45,12 +45,12 @@ export default function VisFactory(Notifier, Private) {
       }
 
       oldConfigs.forEach(function (oldConfig) {
-        let agg = {
+        const agg = {
           schema: schema.name,
           type: oldConfig.agg
         };
 
-        let aggType = aggTypes.byName[agg.type];
+        const aggType = aggTypes.byName[agg.type];
         if (!aggType) {
           notify.log('unable to find an agg type for old confg', oldConfig);
           return;
@@ -131,7 +131,7 @@ export default function VisFactory(Notifier, Private) {
   };
 
   Vis.prototype.hasSchemaAgg = function (schemaName, aggTypeName) {
-    let aggs = this.aggs.bySchemaName[schemaName] || [];
+    const aggs = this.aggs.bySchemaName[schemaName] || [];
     return aggs.some(function (agg) {
       if (!agg.type || !agg.type.name) return false;
       return agg.type.name === aggTypeName;
diff --git a/src/ui/public/vis/vis_type.js b/src/ui/public/vis/vis_type.js
index 96ed7e1d2a00d..e95ec6a36f414 100644
--- a/src/ui/public/vis/vis_type.js
+++ b/src/ui/public/vis/vis_type.js
@@ -1,7 +1,7 @@
 import VisSchemasProvider from 'ui/vis/schemas';
 
 export default function VisTypeFactory(Private) {
-  let VisTypeSchemas = Private(VisSchemasProvider);
+  const VisTypeSchemas = Private(VisSchemasProvider);
 
   function VisType(opts) {
     opts = opts || {};
diff --git a/src/ui/public/vislib/__tests__/components/color.js b/src/ui/public/vislib/__tests__/components/color.js
index 19138ad8ab9cf..b04fbb2cc343d 100644
--- a/src/ui/public/vislib/__tests__/components/color.js
+++ b/src/ui/public/vislib/__tests__/components/color.js
@@ -16,14 +16,14 @@ describe('Vislib Color Module Test Suite', function () {
   describe('Color (main)', function () {
     let previousConfig;
     let getColors;
-    let arr = ['good', 'better', 'best', 'never', 'let', 'it', 'rest'];
-    let arrayOfNumbers = [1, 2, 3, 4, 5];
-    let arrayOfUndefinedValues = [undefined, undefined, undefined];
-    let arrayOfObjects = [{}, {}, {}];
-    let arrayOfBooleans = [true, false, true];
-    let arrayOfNullValues = [null, null, null];
-    let emptyObject = {};
-    let nullValue = null;
+    const arr = ['good', 'better', 'best', 'never', 'let', 'it', 'rest'];
+    const arrayOfNumbers = [1, 2, 3, 4, 5];
+    const arrayOfUndefinedValues = [undefined, undefined, undefined];
+    const arrayOfObjects = [{}, {}, {}];
+    const arrayOfBooleans = [true, false, true];
+    const arrayOfNullValues = [null, null, null];
+    const emptyObject = {};
+    const nullValue = null;
     let notAValue;
     let color;
 
@@ -243,14 +243,14 @@ describe('Vislib Color Module Test Suite', function () {
   });
 
   describe('Color Palette', function () {
-    let num1 = 45;
-    let num2 = 72;
-    let num3 = 90;
-    let string = 'Welcome';
-    let bool = true;
-    let nullValue = null;
-    let emptyArr = [];
-    let emptyObject = {};
+    const num1 = 45;
+    const num2 = 72;
+    const num3 = 90;
+    const string = 'Welcome';
+    const bool = true;
+    const nullValue = null;
+    const emptyArr = [];
+    const emptyObject = {};
     let notAValue;
     let createColorPalette;
     let colorPalette;
diff --git a/src/ui/public/vislib/__tests__/components/labels.js b/src/ui/public/vislib/__tests__/components/labels.js
index f0d7cd5e31c8a..dfbaacdbe0625 100644
--- a/src/ui/public/vislib/__tests__/components/labels.js
+++ b/src/ui/public/vislib/__tests__/components/labels.js
@@ -15,7 +15,7 @@ let rowsArr;
 let uniqLabels;
 let error;
 
-let seriesData = {
+const seriesData = {
   'label': '',
   'series': [
     {
@@ -25,7 +25,7 @@ let seriesData = {
   ]
 };
 
-let rowsData = {
+const rowsData = {
   'rows': [
     {
       'label': 'a',
@@ -66,7 +66,7 @@ let rowsData = {
   ]
 };
 
-let columnsData = {
+const columnsData = {
   'columns': [
     {
       'label': 'a',
@@ -152,23 +152,23 @@ describe('Vislib Labels Module Test Suite', function () {
   });
 
   describe('Data array', function () {
-    let childrenObject = {
+    const childrenObject = {
       children: []
     };
-    let seriesObject = {
+    const seriesObject = {
       series: []
     };
-    let rowsObject = {
+    const rowsObject = {
       rows: []
     };
-    let columnsObject = {
+    const columnsObject = {
       columns: []
     };
-    let string = 'string';
-    let number = 23;
-    let boolean = false;
-    let emptyArray = [];
-    let nullValue = null;
+    const string = 'string';
+    const number = 23;
+    const boolean = false;
+    const emptyArray = [];
+    const nullValue = null;
     let notAValue;
     let dataArray;
     let testSeries;
@@ -267,7 +267,7 @@ describe('Vislib Labels Module Test Suite', function () {
 
   describe('Unique labels', function () {
     let uniqLabels;
-    let arrObj = [
+    const arrObj = [
       {'label': 'a'},
       {'label': 'b'},
       {'label': 'b'},
@@ -276,12 +276,12 @@ describe('Vislib Labels Module Test Suite', function () {
       {'label': 'd'},
       {'label': 'f'}
     ];
-    let string = 'string';
-    let number = 24;
-    let boolean = false;
-    let nullValue = null;
-    let emptyObject = {};
-    let emptyArray = [];
+    const string = 'string';
+    const number = 24;
+    const boolean = false;
+    const nullValue = null;
+    const emptyObject = {};
+    const emptyArray = [];
     let notAValue;
     let uniq;
     let testArr;
@@ -340,18 +340,18 @@ describe('Vislib Labels Module Test Suite', function () {
   });
 
   describe('Get series', function () {
-    let string = 'string';
-    let number = 24;
-    let boolean = false;
-    let nullValue = null;
-    let rowsObject = {
+    const string = 'string';
+    const number = 24;
+    const boolean = false;
+    const nullValue = null;
+    const rowsObject = {
       rows: []
     };
-    let columnsObject = {
+    const columnsObject = {
       columns: []
     };
-    let emptyObject = {};
-    let emptyArray = [];
+    const emptyObject = {};
+    const emptyArray = [];
     let notAValue;
     let getSeries;
     let columnsLabels;
diff --git a/src/ui/public/vislib/__tests__/components/zero_injection.js b/src/ui/public/vislib/__tests__/components/zero_injection.js
index 2393226c1f855..0249c6a6b5a94 100644
--- a/src/ui/public/vislib/__tests__/components/zero_injection.js
+++ b/src/ui/public/vislib/__tests__/components/zero_injection.js
@@ -11,7 +11,7 @@ import VislibComponentsZeroInjectionZeroFilledArrayProvider from 'ui/vislib/comp
 import VislibComponentsZeroInjectionZeroFillDataArrayProvider from 'ui/vislib/components/zero_injection/zero_fill_data_array';
 
 describe('Vislib Zero Injection Module Test Suite', function () {
-  let dateHistogramRows = {
+  const dateHistogramRows = {
     'rows': [
       {
         'label': 'Top 5 @tags: success',
@@ -161,7 +161,7 @@ describe('Vislib Zero Injection Module Test Suite', function () {
     ]
   };
 
-  let seriesData = {
+  const seriesData = {
     series: [
       {
         label: '200',
@@ -176,7 +176,7 @@ describe('Vislib Zero Injection Module Test Suite', function () {
     ]
   };
 
-  let multiSeriesData = {
+  const multiSeriesData = {
     series: [
       {
         label: '200',
@@ -205,7 +205,7 @@ describe('Vislib Zero Injection Module Test Suite', function () {
     ]
   };
 
-  let multiSeriesNumberedData = {
+  const multiSeriesNumberedData = {
     series: [
       {
         label: '200',
@@ -234,24 +234,24 @@ describe('Vislib Zero Injection Module Test Suite', function () {
     ]
   };
 
-  let childrenObject = {
+  const childrenObject = {
     children: []
   };
-  let seriesObject = {
+  const seriesObject = {
     series: []
   };
-  let rowsObject = {
+  const rowsObject = {
     rows: []
   };
-  let columnsObject = {
+  const columnsObject = {
     columns: []
   };
-  let emptyObject = {};
-  let str = 'string';
-  let number = 24;
-  let boolean = false;
-  let nullValue = null;
-  let emptyArray = [];
+  const emptyObject = {};
+  const str = 'string';
+  const number = 24;
+  const boolean = false;
+  const nullValue = null;
+  const emptyArray = [];
   let notAValue;
 
   describe('Zero Injection (main)', function () {
@@ -497,8 +497,8 @@ describe('Vislib Zero Injection Module Test Suite', function () {
 
   describe('Zero Filled Array', function () {
     let createZeroArray;
-    let arr1 = [1, 2, 3, 4, 5];
-    let arr2 = ['1', '2', '3', '4', '5'];
+    const arr1 = [1, 2, 3, 4, 5];
+    const arr2 = ['1', '2', '3', '4', '5'];
     let results1;
     let results2;
 
@@ -578,10 +578,10 @@ describe('Vislib Zero Injection Module Test Suite', function () {
 
   describe('Zero Filled Data Array', function () {
     let zeroFillArray;
-    let xValueArr = [1, 2, 3, 4, 5];
+    const xValueArr = [1, 2, 3, 4, 5];
     let createZeroArray;
     let arr1;
-    let arr2 = [ {x: 3, y: 834} ];
+    const arr2 = [ {x: 3, y: 834} ];
     let results;
 
     beforeEach(ngMock.module('kibana'));
@@ -659,7 +659,7 @@ describe('Vislib Zero Injection Module Test Suite', function () {
     });
 
     it('should return ordered x values', function () {
-      let values = results.rows[0].series[0].values;
+      const values = results.rows[0].series[0].values;
       expect(values[0].x).to.be.lessThan(values[1].x);
       expect(values[1].x).to.be.lessThan(values[2].x);
       expect(values[2].x).to.be.lessThan(values[3].x);
diff --git a/src/ui/public/vislib/__tests__/lib/axis_title.js b/src/ui/public/vislib/__tests__/lib/axis_title.js
index bdb7f08b0701d..d75b3d1028b5a 100644
--- a/src/ui/public/vislib/__tests__/lib/axis_title.js
+++ b/src/ui/public/vislib/__tests__/lib/axis_title.js
@@ -17,7 +17,7 @@ describe('Vislib AxisTitle Class Test Suite', function () {
   let dataObj;
   let xTitle;
   let yTitle;
-  let data = {
+  const data = {
     hits: 621,
     label: '',
     ordered: {
diff --git a/src/ui/public/vislib/__tests__/lib/chart_title.js b/src/ui/public/vislib/__tests__/lib/chart_title.js
index 469949d6d777b..ddb4c6ee0a4e8 100644
--- a/src/ui/public/vislib/__tests__/lib/chart_title.js
+++ b/src/ui/public/vislib/__tests__/lib/chart_title.js
@@ -15,7 +15,7 @@ describe('Vislib ChartTitle Class Test Suite', function () {
   let chartTitle;
   let el;
   let dataObj;
-  let data = {
+  const data = {
     hits: 621,
     label: '',
     ordered: {
diff --git a/src/ui/public/vislib/__tests__/lib/data.js b/src/ui/public/vislib/__tests__/lib/data.js
index 20224d660e6d3..bb6890a60b112 100644
--- a/src/ui/public/vislib/__tests__/lib/data.js
+++ b/src/ui/public/vislib/__tests__/lib/data.js
@@ -9,7 +9,7 @@ import dataStacked from 'fixtures/vislib/mock_data/stacked/_stacked';
 import VislibLibDataProvider from 'ui/vislib/lib/data';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
 
-let seriesData = {
+const seriesData = {
   'label': '',
   'series': [
     {
@@ -19,7 +19,7 @@ let seriesData = {
   ]
 };
 
-let rowsData = {
+const rowsData = {
   'rows': [
     {
       'label': 'a',
@@ -60,7 +60,7 @@ let rowsData = {
   ]
 };
 
-let colsData = {
+const colsData = {
   'columns': [
     {
       'label': 'a',
@@ -117,12 +117,12 @@ describe('Vislib Data Class Test Suite', function () {
     });
 
     it('should return an object', function () {
-      let rowIn = new Data(rowsData, {}, persistedState);
+      const rowIn = new Data(rowsData, {}, persistedState);
       expect(_.isObject(rowIn)).to.be(true);
     });
 
     it('should update label in series data', function () {
-      let seriesDataWithoutLabelInSeries = {
+      const seriesDataWithoutLabelInSeries = {
         'label': '',
         'series': [
           {
@@ -132,12 +132,12 @@ describe('Vislib Data Class Test Suite', function () {
         ],
         'yAxisLabel': 'customLabel'
       };
-      let modifiedData = new Data(seriesDataWithoutLabelInSeries, {}, persistedState);
+      const modifiedData = new Data(seriesDataWithoutLabelInSeries, {}, persistedState);
       expect(modifiedData.data.series[0].label).to.be('customLabel');
     });
 
     it('should update label in row data', function () {
-      let seriesDataWithoutLabelInRow = {
+      const seriesDataWithoutLabelInRow = {
         'rows': [
           {
             'label': '',
@@ -162,13 +162,13 @@ describe('Vislib Data Class Test Suite', function () {
         ],
       };
 
-      let modifiedData = new Data(seriesDataWithoutLabelInRow, {}, persistedState);
+      const modifiedData = new Data(seriesDataWithoutLabelInRow, {}, persistedState);
       expect(modifiedData.data.rows[0].series[0].label).to.be('customLabel');
       expect(modifiedData.data.rows[1].series[0].label).to.be('customLabel');
     });
 
     it('should update label in column data', function () {
-      let seriesDataWithoutLabelInRow = {
+      const seriesDataWithoutLabelInRow = {
         'columns': [
           {
             'label': '',
@@ -194,7 +194,7 @@ describe('Vislib Data Class Test Suite', function () {
         'yAxisLabel': 'customLabel'
       };
 
-      let modifiedData = new Data(seriesDataWithoutLabelInRow, {}, persistedState);
+      const modifiedData = new Data(seriesDataWithoutLabelInRow, {}, persistedState);
       expect(modifiedData.data.columns[0].series[0].label).to.be('customLabel');
       expect(modifiedData.data.columns[1].series[0].label).to.be('customLabel');
     });
@@ -203,7 +203,7 @@ describe('Vislib Data Class Test Suite', function () {
 
   describe('_removeZeroSlices', function () {
     let data;
-    let pieData = {
+    const pieData = {
       slices: {
         children: [
           {size: 30},
@@ -218,7 +218,7 @@ describe('Vislib Data Class Test Suite', function () {
     });
 
     it('should remove zero values', function () {
-      let slices = data._removeZeroSlices(data.data.slices);
+      const slices = data._removeZeroSlices(data.data.slices);
       expect(slices.children.length).to.be(2);
     });
   });
@@ -250,8 +250,8 @@ describe('Vislib Data Class Test Suite', function () {
 
     function testLength(inputData) {
       return function () {
-        let data = new Data(inputData, {}, persistedState);
-        let len = _.reduce(data.chartData(), function (sum, chart) {
+        const data = new Data(inputData, {}, persistedState);
+        const len = _.reduce(data.chartData(), function (sum, chart) {
           return sum + chart.series.reduce(function (sum, series) {
             return sum + series.values.length;
           }, 0);
@@ -266,9 +266,9 @@ describe('Vislib Data Class Test Suite', function () {
     let visData;
     let visDataNeg;
     let visDataStacked;
-    let minValue = 4;
-    let minValueNeg = -41;
-    let minValueStacked = 15;
+    const minValue = 4;
+    const minValueNeg = -41;
+    const minValueStacked = 15;
 
     beforeEach(function () {
       visData = new Data(dataSeries, {}, persistedState);
@@ -286,15 +286,15 @@ describe('Vislib Data Class Test Suite', function () {
     });
 
     it('should have a minimum date value that is greater than the max value within the date range', function () {
-      let series = _.pluck(visData.chartData(), 'series');
-      let stackedSeries = _.pluck(visDataStacked.chartData(), 'series');
+      const series = _.pluck(visData.chartData(), 'series');
+      const stackedSeries = _.pluck(visDataStacked.chartData(), 'series');
       expect(_.min(series.values, function (d) { return d.x; })).to.be.greaterThan(minValue);
       expect(_.min(stackedSeries.values, function (d) { return d.x; })).to.be.greaterThan(minValueStacked);
     });
 
     it('allows passing a value getter for manipulating the values considered', function () {
-      let realMin = visData.getYMin();
-      let multiplier = 13.2;
+      const realMin = visData.getYMin();
+      const multiplier = 13.2;
       expect(visData.getYMin(function (d) { return d.y * multiplier; })).to.be(realMin * multiplier);
     });
   });
@@ -303,9 +303,9 @@ describe('Vislib Data Class Test Suite', function () {
     let visData;
     let visDataNeg;
     let visDataStacked;
-    let maxValue = 41;
-    let maxValueNeg = -4;
-    let maxValueStacked = 115;
+    const maxValue = 41;
+    const maxValueNeg = -4;
+    const maxValueStacked = 115;
 
     beforeEach(function () {
       visData = new Data(dataSeries, {}, persistedState);
@@ -323,22 +323,22 @@ describe('Vislib Data Class Test Suite', function () {
     });
 
     it('should have a minimum date value that is greater than the max value within the date range', function () {
-      let series = _.pluck(visData.chartData(), 'series');
-      let stackedSeries = _.pluck(visDataStacked.chartData(), 'series');
+      const series = _.pluck(visData.chartData(), 'series');
+      const stackedSeries = _.pluck(visDataStacked.chartData(), 'series');
       expect(_.min(series, function (d) { return d.x; })).to.be.greaterThan(maxValue);
       expect(_.min(stackedSeries, function (d) { return d.x; })).to.be.greaterThan(maxValueStacked);
     });
 
     it('allows passing a value getter for manipulating the values considered', function () {
-      let realMax = visData.getYMax();
-      let multiplier = 13.2;
+      const realMax = visData.getYMax();
+      const multiplier = 13.2;
       expect(visData.getYMax(function (d) { return d.y * multiplier; })).to.be(realMax * multiplier);
     });
   });
 
   describe('geohashGrid methods', function () {
     let data;
-    let geohashGridData = {
+    const geohashGridData = {
       hits: 3954,
       rows: [{
         title: 'Top 5 _type: apache',
@@ -381,14 +381,14 @@ describe('Vislib Data Class Test Suite', function () {
 
     describe('getVisData', function () {
       it('should return the rows property', function () {
-        let visData = data.getVisData();
+        const visData = data.getVisData();
         expect(visData).to.eql(geohashGridData.rows);
       });
     });
 
     describe('getGeoExtents', function () {
       it('should return the min and max geoJson properties', function () {
-        let minMax = data.getGeoExtents();
+        const minMax = data.getGeoExtents();
         expect(minMax.min).to.be(1);
         expect(minMax.max).to.be(331);
       });
@@ -397,12 +397,12 @@ describe('Vislib Data Class Test Suite', function () {
 
   describe('null value check', function () {
     it('should return false', function () {
-      let data = new Data(rowsData, {}, persistedState);
+      const data = new Data(rowsData, {}, persistedState);
       expect(data.hasNullValues()).to.be(false);
     });
 
     it('should return true', function () {
-      let nullRowData = { rows: rowsData.rows.slice(0) };
+      const nullRowData = { rows: rowsData.rows.slice(0) };
       nullRowData.rows.push({
         'label': 'e',
         'series': [
@@ -413,7 +413,7 @@ describe('Vislib Data Class Test Suite', function () {
         ]
       });
 
-      let data = new Data(nullRowData, {}, persistedState);
+      const data = new Data(nullRowData, {}, persistedState);
       expect(data.hasNullValues()).to.be(true);
     });
   });
diff --git a/src/ui/public/vislib/__tests__/lib/dispatch.js b/src/ui/public/vislib/__tests__/lib/dispatch.js
index 2fedc6a239ca2..c3ff53ddedeca 100644
--- a/src/ui/public/vislib/__tests__/lib/dispatch.js
+++ b/src/ui/public/vislib/__tests__/lib/dispatch.js
@@ -39,7 +39,7 @@ describe('Vislib Dispatch Class Test Suite', function () {
     });
 
     it('extends the SimpleEmitter class', function () {
-      let events = _.pluck(vis.handler.charts, 'events');
+      const events = _.pluck(vis.handler.charts, 'events');
       expect(events.length).to.be.above(0);
       events.forEach(function (dispatch) {
         expect(dispatch).to.be.a(SimpleEmitter);
@@ -65,11 +65,11 @@ describe('Vislib Dispatch Class Test Suite', function () {
 
     describe('addEvent method', function () {
       it('returns a function that binds the passed event to a selection', function () {
-        let chart = _.first(vis.handler.charts);
-        let apply = chart.events.addEvent('event', _.noop);
+        const chart = _.first(vis.handler.charts);
+        const apply = chart.events.addEvent('event', _.noop);
         expect(apply).to.be.a('function');
 
-        let els = getEls(vis.el, 3, 'div');
+        const els = getEls(vis.el, 3, 'div');
         apply(els);
         els.each(function () {
           expect(d3.select(this).on('event')).to.be(_.noop);
@@ -88,11 +88,11 @@ describe('Vislib Dispatch Class Test Suite', function () {
         });
 
         it('returns a function that binds ' + event + ' events to a selection', function () {
-          let chart = _.first(vis.handler.charts);
-          let apply = chart.events[name](d3.select(document.createElement('svg')));
+          const chart = _.first(vis.handler.charts);
+          const apply = chart.events[name](d3.select(document.createElement('svg')));
           expect(apply).to.be.a('function');
 
-          let els = getEls(vis.el, 3, 'div');
+          const els = getEls(vis.el, 3, 'div');
           apply(els);
           els.each(function () {
             expect(d3.select(this).on(event)).to.be.a('function');
@@ -109,7 +109,7 @@ describe('Vislib Dispatch Class Test Suite', function () {
     describe('addMousePointer method', function () {
       it('should be a function', function () {
         vis.handler.charts.forEach(function (chart) {
-          let pointer = chart.events.addMousePointer;
+          const pointer = chart.events.addMousePointer;
 
           expect(_.isFunction(pointer)).to.be(true);
         });
diff --git a/src/ui/public/vislib/__tests__/lib/handler/handler.js b/src/ui/public/vislib/__tests__/lib/handler/handler.js
index 6953e3ebef2e0..e5e66c81cab51 100644
--- a/src/ui/public/vislib/__tests__/lib/handler/handler.js
+++ b/src/ui/public/vislib/__tests__/lib/handler/handler.js
@@ -12,13 +12,13 @@ import $ from 'jquery';
 import VislibLibHandlerHandlerProvider from 'ui/vislib/lib/handler/handler';
 import FixturesVislibVisFixtureProvider from 'fixtures/vislib/_vis_fixture';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
-let dateHistogramArray = [
+const dateHistogramArray = [
   series,
   columns,
   rows,
   stackedSeries
 ];
-let names = [
+const names = [
   'series',
   'columns',
   'rows',
@@ -30,7 +30,7 @@ dateHistogramArray.forEach(function (data, i) {
     let Handler;
     let vis;
     let persistedState;
-    let events = [
+    const events = [
       'click',
       'brush'
     ];
diff --git a/src/ui/public/vislib/__tests__/lib/layout/layout.js b/src/ui/public/vislib/__tests__/lib/layout/layout.js
index a69e53aa89235..58179fbb1efdc 100644
--- a/src/ui/public/vislib/__tests__/lib/layout/layout.js
+++ b/src/ui/public/vislib/__tests__/lib/layout/layout.js
@@ -12,13 +12,13 @@ import $ from 'jquery';
 import VislibLibLayoutLayoutProvider from 'ui/vislib/lib/layout/layout';
 import FixturesVislibVisFixtureProvider from 'fixtures/vislib/_vis_fixture';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
-let dateHistogramArray = [
+const dateHistogramArray = [
   series,
   columns,
   rows,
   stackedSeries
 ];
-let names = [
+const names = [
   'series',
   'columns',
   'rows',
diff --git a/src/ui/public/vislib/__tests__/lib/layout/splits/column_chart/splits.js b/src/ui/public/vislib/__tests__/lib/layout/splits/column_chart/splits.js
index 2ec53d8c8e990..a4d8a02039fd1 100644
--- a/src/ui/public/vislib/__tests__/lib/layout/splits/column_chart/splits.js
+++ b/src/ui/public/vislib/__tests__/lib/layout/splits/column_chart/splits.js
@@ -15,7 +15,7 @@ describe('Vislib Split Function Test Suite', function () {
     let xAxisSplit;
     let yAxisSplit;
     let el;
-    let data = {
+    const data = {
       rows: [
         {
           hits      : 621,
diff --git a/src/ui/public/vislib/__tests__/lib/layout/types/column_layout.js b/src/ui/public/vislib/__tests__/lib/layout/types/column_layout.js
index f500ad8dcb534..6ac42cbe9b52f 100644
--- a/src/ui/public/vislib/__tests__/lib/layout/types/column_layout.js
+++ b/src/ui/public/vislib/__tests__/lib/layout/types/column_layout.js
@@ -9,7 +9,7 @@ describe('Vislib Column Layout Test Suite', function () {
   let layoutType;
   let columnLayout;
   let el;
-  let data = {
+  const data = {
     hits: 621,
     label: '',
     ordered: {
diff --git a/src/ui/public/vislib/__tests__/lib/resize_checker.js b/src/ui/public/vislib/__tests__/lib/resize_checker.js
index f4bdb6b70622b..bafaef16eaf2d 100644
--- a/src/ui/public/vislib/__tests__/lib/resize_checker.js
+++ b/src/ui/public/vislib/__tests__/lib/resize_checker.js
@@ -16,7 +16,7 @@ describe('Vislib Resize Checker', function () {
   let EventEmitter;
   let checker;
   let reflowWatcher;
-  let reflowSpies = {};
+  const reflowSpies = {};
 
   beforeEach(ngMock.module('kibana'));
 
@@ -27,7 +27,7 @@ describe('Vislib Resize Checker', function () {
     reflowSpies.on = sinon.spy(reflowWatcher, 'on');
     reflowSpies.off = sinon.spy(reflowWatcher, 'off');
 
-    let $el = $(document.createElement('div'))
+    const $el = $(document.createElement('div'))
     .appendTo('body')
     .css('visibility', 'hidden')
     .get(0);
@@ -47,7 +47,7 @@ describe('Vislib Resize Checker', function () {
 
     it('listens for the "reflow" event of the reflowWatchers', function () {
       expect(reflowSpies.on).to.have.property('callCount', 1);
-      let call = reflowSpies.on.getCall(0);
+      const call = reflowSpies.on.getCall(0);
       expect(call.args[0]).to.be('reflow');
     });
 
@@ -63,8 +63,8 @@ describe('Vislib Resize Checker', function () {
 
   describe('#read', function () {
     it('gets the proper dimensions for the element', function () {
-      let dimensions = checker.read();
-      let windowWidth = document.documentElement.clientWidth;
+      const dimensions = checker.read();
+      const windowWidth = document.documentElement.clientWidth;
 
       expect(dimensions.w).to.equal(windowWidth);
       expect(dimensions.h).to.equal(0);
@@ -73,7 +73,7 @@ describe('Vislib Resize Checker', function () {
 
   describe('#saveSize', function () {
     it('calls #read() when no arg is passed', function () {
-      let stub = sinon.stub(checker, 'read').returns({});
+      const stub = sinon.stub(checker, 'read').returns({});
 
       checker.saveSize();
 
@@ -81,7 +81,7 @@ describe('Vislib Resize Checker', function () {
     });
 
     it('saves the size of the element', function () {
-      let football = {};
+      const football = {};
       checker.saveSize(football);
       expect(checker).to.have.property('_savedSize', football);
     });
@@ -123,12 +123,12 @@ describe('Vislib Resize Checker', function () {
     });
 
     it('emits "resize" based on MS_MAX_RESIZE_DELAY, even if el\'s constantly changing size', function () {
-      let steps = _.random(5, 10);
+      const steps = _.random(5, 10);
       this.slow(steps * 10);
 
       // we are going to fake the delay using the fake clock
-      let msStep = Math.floor(ResizeChecker.MS_MAX_RESIZE_DELAY / (steps - 1));
-      let clock = sinon.useFakeTimers();
+      const msStep = Math.floor(ResizeChecker.MS_MAX_RESIZE_DELAY / (steps - 1));
+      const clock = sinon.useFakeTimers();
 
       _.times(steps, function step(i) {
         checker.$el.css('height', 100 + i);
@@ -145,8 +145,8 @@ describe('Vislib Resize Checker', function () {
 
   describe('#destroy()', function () {
     it('removes the "reflow" event from the reflowWatcher', function () {
-      let onCall = reflowSpies.on.getCall(0);
-      let handler = onCall.args[1];
+      const onCall = reflowSpies.on.getCall(0);
+      const handler = onCall.args[1];
 
       checker.destroy();
       expect(reflowSpies.off).to.have.property('callCount', 1);
@@ -154,7 +154,7 @@ describe('Vislib Resize Checker', function () {
     });
 
     it('clears the timeout', function () {
-      let spy = sinon.spy(window, 'clearTimeout');
+      const spy = sinon.spy(window, 'clearTimeout');
       checker.destroy();
       expect(spy).to.have.property('callCount', 1);
     });
@@ -193,9 +193,9 @@ describe('Vislib Resize Checker', function () {
         timerId = checker.continueSchedule();
       }
 
-      let last = _.last(schedule);
+      const last = _.last(schedule);
       _.times(5, function () {
-        let timer = clock.timers[checker.continueSchedule()];
+        const timer = clock.timers[checker.continueSchedule()];
         expect(timer).to.have.property('callAt', last);
       });
     });
diff --git a/src/ui/public/vislib/__tests__/lib/x_axis.js b/src/ui/public/vislib/__tests__/lib/x_axis.js
index 7b9ea1a5b3e03..d42e135477109 100644
--- a/src/ui/public/vislib/__tests__/lib/x_axis.js
+++ b/src/ui/public/vislib/__tests__/lib/x_axis.js
@@ -16,7 +16,7 @@ describe('Vislib xAxis Class Test Suite', function () {
   let el;
   let fixture;
   let dataObj;
-  let data = {
+  const data = {
     hits: 621,
     label: '',
     ordered: {
diff --git a/src/ui/public/vislib/__tests__/lib/y_axis.js b/src/ui/public/vislib/__tests__/lib/y_axis.js
index d89c1febb3003..19e5ab0883146 100644
--- a/src/ui/public/vislib/__tests__/lib/y_axis.js
+++ b/src/ui/public/vislib/__tests__/lib/y_axis.js
@@ -15,7 +15,7 @@ let buildYAxis;
 let yAxis;
 let yAxisDiv;
 
-let timeSeries = [
+const timeSeries = [
   1408734060000,
   1408734090000,
   1408734120000,
@@ -28,7 +28,7 @@ let timeSeries = [
   1408734330000
 ];
 
-let defaultGraphData = [
+const defaultGraphData = [
   [ 8, 23, 30, 28, 36, 30, 26, 22, 29, 24 ],
   [ 2, 13, 20, 18, 26, 20, 16, 12, 19, 14 ]
 ];
@@ -43,7 +43,7 @@ function makeSeriesData(data) {
 }
 
 function createData(seriesData) {
-  let data = {
+  const data = {
     hits: 621,
     label: 'test',
     ordered: {
@@ -59,7 +59,7 @@ function createData(seriesData) {
     yAxisLabel: 'Count'
   };
 
-  let node = $('<div>').css({
+  const node = $('<div>').css({
     height: 40,
     width: 40
   })
@@ -72,7 +72,7 @@ function createData(seriesData) {
   yAxisDiv = el.append('div')
   .attr('class', 'y-axis-div');
 
-  let dataObj = new Data(data, {
+  const dataObj = new Data(data, {
     defaultYMin: true
   }, persistedState);
 
@@ -133,10 +133,10 @@ describe('Vislib yAxis Class Test Suite', function () {
     let yScale;
     let graphData;
     let domain;
-    let height = 50;
+    const height = 50;
 
     function checkDomain(min, max) {
-      let domain = yScale.domain();
+      const domain = yScale.domain();
       expect(domain[0]).to.be.lessThan(min + 1);
       expect(domain[1]).to.be.greaterThan(max - 1);
       return domain;
@@ -181,9 +181,9 @@ describe('Vislib yAxis Class Test Suite', function () {
 
 
       it('should have domain between 0 and max value', function () {
-        let min = 0;
-        let max = _.max(_.flattenDeep(graphData));
-        let domain = checkDomain(min, max);
+        const min = 0;
+        const max = _.max(_.flattenDeep(graphData));
+        const domain = checkDomain(min, max);
         expect(domain[1]).to.be.greaterThan(0);
         checkRange();
       });
@@ -200,9 +200,9 @@ describe('Vislib yAxis Class Test Suite', function () {
       });
 
       it('should have domain between min value and 0', function () {
-        let min = _.min(_.flattenDeep(graphData));
-        let max = 0;
-        let domain = checkDomain(min, max);
+        const min = _.min(_.flattenDeep(graphData));
+        const max = 0;
+        const domain = checkDomain(min, max);
         expect(domain[0]).to.be.lessThan(0);
         checkRange();
       });
@@ -219,9 +219,9 @@ describe('Vislib yAxis Class Test Suite', function () {
       });
 
       it('should have domain between min and max values', function () {
-        let min = _.min(_.flattenDeep(graphData));
-        let max = _.max(_.flattenDeep(graphData));
-        let domain = checkDomain(min, max);
+        const min = _.min(_.flattenDeep(graphData));
+        const max = _.max(_.flattenDeep(graphData));
+        const domain = checkDomain(min, max);
         expect(domain[0]).to.be.lessThan(0);
         expect(domain[1]).to.be.greaterThan(0);
         checkRange();
@@ -236,8 +236,8 @@ describe('Vislib yAxis Class Test Suite', function () {
       });
 
       it('should throw a NaN error', function () {
-        let min = 'Not a number';
-        let max = 12;
+        const min = 'Not a number';
+        const max = 12;
 
         expect(function () {
           yAxis._validateUserExtents(min, max);
@@ -250,7 +250,7 @@ describe('Vislib yAxis Class Test Suite', function () {
         domain = [];
         domain[0] = yAxis._attr.yAxis.min = 20;
         domain[1] = yAxis._attr.yAxis.max = 80;
-        let newDomain = yAxis._validateUserExtents(domain);
+        const newDomain = yAxis._validateUserExtents(domain);
 
         expect(newDomain[0]).to.be(domain[0] / 100);
         expect(newDomain[1]).to.be(domain[1] / 100);
@@ -258,7 +258,7 @@ describe('Vislib yAxis Class Test Suite', function () {
 
       it('should return the user defined value', function () {
         domain = [20, 50];
-        let newDomain = yAxis._validateUserExtents(domain);
+        const newDomain = yAxis._validateUserExtents(domain);
 
         expect(newDomain[0]).to.be(domain[0]);
         expect(newDomain[1]).to.be(domain[1]);
@@ -267,8 +267,8 @@ describe('Vislib yAxis Class Test Suite', function () {
 
     describe('should throw an error when', function () {
       it('min === max', function () {
-        let min = 12;
-        let max = 12;
+        const min = 12;
+        const max = 12;
 
         expect(function () {
           yAxis._validateAxisExtents(min, max);
@@ -276,8 +276,8 @@ describe('Vislib yAxis Class Test Suite', function () {
       });
 
       it('min > max', function () {
-        let min = 30;
-        let max = 10;
+        const min = 30;
+        const max = 10;
 
         expect(function () {
           yAxis._validateAxisExtents(min, max);
@@ -287,7 +287,7 @@ describe('Vislib yAxis Class Test Suite', function () {
   });
 
   describe('getScaleType method', function () {
-    let fnNames = ['linear', 'log', 'square root'];
+    const fnNames = ['linear', 'log', 'square root'];
 
     it('should return a function', function () {
       fnNames.forEach(function (fnName) {
@@ -319,7 +319,7 @@ describe('Vislib yAxis Class Test Suite', function () {
     });
 
     it('should return a yMin value of 1', function () {
-      let yMin = yAxis._logDomain(0, 200)[0];
+      const yMin = yAxis._logDomain(0, 200)[0];
       expect(yMin).to.be(1);
     });
   });
@@ -343,13 +343,13 @@ describe('Vislib yAxis Class Test Suite', function () {
 
     it('should use percentage format for percentages', function () {
       yAxis._attr.mode = 'percentage';
-      let tickFormat = yAxis.getYAxis().tickFormat();
+      const tickFormat = yAxis.getYAxis().tickFormat();
       expect(tickFormat(1)).to.be('100%');
     });
 
     it('should use decimal format for small values', function () {
       yAxis.yMax = 1;
-      let tickFormat = yAxis.getYAxis().tickFormat();
+      const tickFormat = yAxis.getYAxis().tickFormat();
       expect(tickFormat(0.8)).to.be('0.8');
     });
 
@@ -384,23 +384,23 @@ describe('Vislib yAxis Class Test Suite', function () {
   });
 
   describe('#tickFormat()', function () {
-    let formatter = function () {};
+    const formatter = function () {};
 
     it('returns a basic number formatter by default', function () {
-      let yAxis = buildYAxis();
+      const yAxis = buildYAxis();
       expect(yAxis.tickFormat()).to.not.be(formatter);
       expect(yAxis.tickFormat()(1)).to.be('1');
     });
 
     it('returns the yAxisFormatter when passed', function () {
-      let yAxis = buildYAxis({
+      const yAxis = buildYAxis({
         yAxisFormatter: formatter
       });
       expect(yAxis.tickFormat()).to.be(formatter);
     });
 
     it('returns a percentage formatter when the vis is in percentage mode', function () {
-      let yAxis = buildYAxis({
+      const yAxis = buildYAxis({
         yAxisFormatter: formatter,
         _attr: {
           mode: 'percentage'
diff --git a/src/ui/public/vislib/__tests__/vis.js b/src/ui/public/vislib/__tests__/vis.js
index 9129ca2a9d84c..6f3f28cb66553 100644
--- a/src/ui/public/vislib/__tests__/vis.js
+++ b/src/ui/public/vislib/__tests__/vis.js
@@ -11,14 +11,14 @@ import $ from 'jquery';
 import FixturesVislibVisFixtureProvider from 'fixtures/vislib/_vis_fixture';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
 
-let dataArray = [
+const dataArray = [
   series,
   columns,
   rows,
   stackedSeries
 ];
 
-let names = [
+const names = [
   'series',
   'columns',
   'rows',
@@ -28,8 +28,8 @@ let names = [
 
 dataArray.forEach(function (data, i) {
   describe('Vislib Vis Test Suite for ' + names[i] + ' Data', function () {
-    let beforeEvent = 'click';
-    let afterEvent = 'brush';
+    const beforeEvent = 'click';
+    const afterEvent = 'brush';
     let vis;
     let persistedState;
     let secondVis;
@@ -129,7 +129,7 @@ dataArray.forEach(function (data, i) {
     });
 
     describe('on Method', function () {
-      let events = [
+      const events = [
         beforeEvent,
         afterEvent
       ];
@@ -173,7 +173,7 @@ dataArray.forEach(function (data, i) {
       });
 
       it('should cause a listener for each event to be attached to each chart', function () {
-        let charts = vis.handler.charts;
+        const charts = vis.handler.charts;
 
         charts.forEach(function (chart, i) {
           expect(chart.events.listenerCount(beforeEvent)).to.be.above(0);
@@ -220,7 +220,7 @@ dataArray.forEach(function (data, i) {
       });
 
       it('should remove a listener', function () {
-        let charts = vis.handler.charts;
+        const charts = vis.handler.charts;
 
         expect(vis.listeners(beforeEvent)).to.not.contain(listener1);
         expect(vis.listeners(beforeEvent)).to.contain(listener2);
@@ -236,7 +236,7 @@ dataArray.forEach(function (data, i) {
       });
 
       it('should remove the event and all listeners when only event passed an argument', function () {
-        let charts = vis.handler.charts;
+        const charts = vis.handler.charts;
         vis.off(afterEvent);
 
         // should remove 'brush' event
@@ -251,7 +251,7 @@ dataArray.forEach(function (data, i) {
       });
 
       it('should remove the event from the chart when the last listener is removed', function () {
-        let charts = vis.handler.charts;
+        const charts = vis.handler.charts;
         vis.off(afterEvent, listener2);
 
         expect(vis.listenerCount(afterEvent)).to.be(0);
diff --git a/src/ui/public/vislib/__tests__/visualizations/area_chart.js b/src/ui/public/vislib/__tests__/visualizations/area_chart.js
index 72c125746e223..08d021450e48c 100644
--- a/src/ui/public/vislib/__tests__/visualizations/area_chart.js
+++ b/src/ui/public/vislib/__tests__/visualizations/area_chart.js
@@ -9,7 +9,7 @@ import notQuiteEnoughVariables from 'fixtures/vislib/mock_data/not_enough_data/_
 import $ from 'jquery';
 import FixturesVislibVisFixtureProvider from 'fixtures/vislib/_vis_fixture';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
-let someOtherVariables = {
+const someOtherVariables = {
   'series pos': require('fixtures/vislib/mock_data/date_histogram/_series'),
   'series pos neg': require('fixtures/vislib/mock_data/date_histogram/_series_pos_neg'),
   'series neg': require('fixtures/vislib/mock_data/date_histogram/_series_neg'),
@@ -18,7 +18,7 @@ let someOtherVariables = {
   'stackedSeries': require('fixtures/vislib/mock_data/date_histogram/_stacked_series')
 };
 
-let visLibParams = {
+const visLibParams = {
   type: 'area',
   addLegend: true,
   addTooltip: true
@@ -158,12 +158,12 @@ _.forOwn(someOtherVariables, function (variablesAreCool, imaVariable) {
 
       it('should not draw circles where d.y === 0', function () {
         vis.handler.charts.forEach(function (chart) {
-          let series = chart.chartData.series;
-          let isZero = series.some(function (d) {
+          const series = chart.chartData.series;
+          const isZero = series.some(function (d) {
             return d.y === 0;
           });
-          let circles = $.makeArray($(chart.chartEl).find('circle'));
-          let isNotDrawn = circles.some(function (d) {
+          const circles = $.makeArray($(chart.chartEl).find('circle'));
+          const isNotDrawn = circles.some(function (d) {
             return d.__data__.y === 0;
           });
 
@@ -183,7 +183,7 @@ _.forOwn(someOtherVariables, function (variablesAreCool, imaVariable) {
 
       it('should return a yMin and yMax', function () {
         vis.handler.charts.forEach(function (chart) {
-          let yAxis = chart.handler.yAxis;
+          const yAxis = chart.handler.yAxis;
 
           expect(yAxis.domain[0]).to.not.be(undefined);
           expect(yAxis.domain[1]).to.not.be(undefined);
@@ -192,7 +192,7 @@ _.forOwn(someOtherVariables, function (variablesAreCool, imaVariable) {
 
       it('should render a zero axis line', function () {
         vis.handler.charts.forEach(function (chart) {
-          let yAxis = chart.handler.yAxis;
+          const yAxis = chart.handler.yAxis;
 
           if (yAxis.yMin < 0 && yAxis.yMax > 0) {
             expect($(chart.chartEl).find('line.zero-line').length).to.be(1);
@@ -224,8 +224,8 @@ _.forOwn(someOtherVariables, function (variablesAreCool, imaVariable) {
 
       it('should return yAxis extents equal to data extents', function () {
         vis.handler.charts.forEach(function (chart) {
-          let yAxis = chart.handler.yAxis;
-          let yVals = [vis.handler.data.getYMin(), vis.handler.data.getYMax()];
+          const yAxis = chart.handler.yAxis;
+          const yVals = [vis.handler.data.getYMin(), vis.handler.data.getYMax()];
 
           expect(yAxis.domain[0]).to.equal(yVals[0]);
           expect(yAxis.domain[1]).to.equal(yVals[1]);
diff --git a/src/ui/public/vislib/__tests__/visualizations/chart.js b/src/ui/public/vislib/__tests__/visualizations/chart.js
index 44f178d660ee9..154fabfd8f290 100644
--- a/src/ui/public/vislib/__tests__/visualizations/chart.js
+++ b/src/ui/public/vislib/__tests__/visualizations/chart.js
@@ -13,12 +13,12 @@ describe('Vislib _chart Test Suite', function () {
   let Data;
   let persistedState;
   let Vis;
-  let chartData = {};
+  const chartData = {};
   let vis;
   let el;
   let myChart;
   let config;
-  let data = {
+  const data = {
     hits      : 621,
     label     : '',
     ordered   : {
diff --git a/src/ui/public/vislib/__tests__/visualizations/column_chart.js b/src/ui/public/vislib/__tests__/visualizations/column_chart.js
index e168d039513b5..d0b1acb9d9bbc 100644
--- a/src/ui/public/vislib/__tests__/visualizations/column_chart.js
+++ b/src/ui/public/vislib/__tests__/visualizations/column_chart.js
@@ -17,7 +17,7 @@ import FixturesVislibVisFixtureProvider from 'fixtures/vislib/_vis_fixture';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
 
 // tuple, with the format [description, mode, data]
-let dataTypesArray = [
+const dataTypesArray = [
   ['series', 'stacked', series],
   ['series with positive and negative values', 'stacked', seriesPosNeg],
   ['series with negative values', 'stacked', seriesNeg],
@@ -27,14 +27,14 @@ let dataTypesArray = [
 ];
 
 dataTypesArray.forEach(function (dataType, i) {
-  let name = dataType[0];
-  let mode = dataType[1];
-  let data = dataType[2];
+  const name = dataType[0];
+  const mode = dataType[1];
+  const data = dataType[2];
 
   describe('Vislib Column Chart Test Suite for ' + name + ' Data', function () {
     let vis;
     let persistedState;
-    let visLibParams = {
+    const visLibParams = {
       type: 'histogram',
       hasTimeField: true,
       addLegend: true,
@@ -104,7 +104,7 @@ dataTypesArray.forEach(function (dataType, i) {
 
     describe('addBarEvents method', function () {
       function checkChart(chart) {
-        let rect = $(chart.chartEl).find('.series rect').get(0);
+        const rect = $(chart.chartEl).find('.series rect').get(0);
 
         // check for existance of stuff and things
         return {
@@ -121,23 +121,23 @@ dataTypesArray.forEach(function (dataType, i) {
 
       it('should attach the brush if data is a set of ordered dates', function () {
         vis.handler.charts.forEach(function (chart) {
-          let has = checkChart(chart);
-          let ordered = vis.handler.data.get('ordered');
-          let date = Boolean(ordered && ordered.date);
+          const has = checkChart(chart);
+          const ordered = vis.handler.data.get('ordered');
+          const date = Boolean(ordered && ordered.date);
           expect(has.brush).to.be(date);
         });
       });
 
       it('should attach a click event', function () {
         vis.handler.charts.forEach(function (chart) {
-          let has = checkChart(chart);
+          const has = checkChart(chart);
           expect(has.click).to.be(true);
         });
       });
 
       it('should attach a hover event', function () {
         vis.handler.charts.forEach(function (chart) {
-          let has = checkChart(chart);
+          const has = checkChart(chart);
           expect(has.mouseOver).to.be(true);
         });
       });
@@ -152,7 +152,7 @@ dataTypesArray.forEach(function (dataType, i) {
 
       it('should return a yMin and yMax', function () {
         vis.handler.charts.forEach(function (chart) {
-          let yAxis = chart.handler.yAxis;
+          const yAxis = chart.handler.yAxis;
 
           expect(yAxis.domain[0]).to.not.be(undefined);
           expect(yAxis.domain[1]).to.not.be(undefined);
@@ -161,7 +161,7 @@ dataTypesArray.forEach(function (dataType, i) {
 
       it('should render a zero axis line', function () {
         vis.handler.charts.forEach(function (chart) {
-          let yAxis = chart.handler.yAxis;
+          const yAxis = chart.handler.yAxis;
 
           if (yAxis.yMin < 0 && yAxis.yMax > 0) {
             expect($(chart.chartEl).find('line.zero-line').length).to.be(1);
@@ -193,9 +193,9 @@ dataTypesArray.forEach(function (dataType, i) {
 
       it('should return yAxis extents equal to data extents', function () {
         vis.handler.charts.forEach(function (chart) {
-          let yAxis = chart.handler.yAxis;
-          let min = vis.handler.data.getYMin();
-          let max = vis.handler.data.getYMax();
+          const yAxis = chart.handler.yAxis;
+          const min = vis.handler.data.getYMin();
+          const max = vis.handler.data.getYMax();
 
           expect(yAxis.domain[0]).to.equal(min);
           expect(yAxis.domain[1]).to.equal(max);
diff --git a/src/ui/public/vislib/__tests__/visualizations/line_chart.js b/src/ui/public/vislib/__tests__/visualizations/line_chart.js
index bd4ffcb7b5885..0c4b02c99ace4 100644
--- a/src/ui/public/vislib/__tests__/visualizations/line_chart.js
+++ b/src/ui/public/vislib/__tests__/visualizations/line_chart.js
@@ -15,7 +15,7 @@ import $ from 'jquery';
 import FixturesVislibVisFixtureProvider from 'fixtures/vislib/_vis_fixture';
 import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_state';
 
-let dataTypes = [
+const dataTypes = [
   ['series pos', seriesPos],
   ['series pos neg', seriesPosNeg],
   ['series neg', seriesNeg],
@@ -26,8 +26,8 @@ let dataTypes = [
 
 describe('Vislib Line Chart', function () {
   dataTypes.forEach(function (type, i) {
-    let name = type[0];
-    let data = type[1];
+    const name = type[0];
+    const data = type[1];
 
     describe(name + ' Data', function () {
       let vis;
@@ -35,7 +35,7 @@ describe('Vislib Line Chart', function () {
 
       beforeEach(ngMock.module('kibana'));
       beforeEach(ngMock.inject(function (Private) {
-        let visLibParams = {
+        const visLibParams = {
           type: 'line',
           addLegend: true,
           addTooltip: true,
@@ -133,7 +133,7 @@ describe('Vislib Line Chart', function () {
 
         it('should return a yMin and yMax', function () {
           vis.handler.charts.forEach(function (chart) {
-            let yAxis = chart.handler.yAxis;
+            const yAxis = chart.handler.yAxis;
 
             expect(yAxis.domain[0]).to.not.be(undefined);
             expect(yAxis.domain[1]).to.not.be(undefined);
@@ -142,7 +142,7 @@ describe('Vislib Line Chart', function () {
 
         it('should render a zero axis line', function () {
           vis.handler.charts.forEach(function (chart) {
-            let yAxis = chart.handler.yAxis;
+            const yAxis = chart.handler.yAxis;
 
             if (yAxis.yMin < 0 && yAxis.yMax > 0) {
               expect($(chart.chartEl).find('line.zero-line').length).to.be(1);
@@ -174,8 +174,8 @@ describe('Vislib Line Chart', function () {
 
         it('should return yAxis extents equal to data extents', function () {
           vis.handler.charts.forEach(function (chart) {
-            let yAxis = chart.handler.yAxis;
-            let yVals = [vis.handler.data.getYMin(), vis.handler.data.getYMax()];
+            const yAxis = chart.handler.yAxis;
+            const yVals = [vis.handler.data.getYMin(), vis.handler.data.getYMax()];
 
             expect(yAxis.domain[0]).to.equal(yVals[0]);
             expect(yAxis.domain[1]).to.equal(yVals[1]);
diff --git a/src/ui/public/vislib/__tests__/visualizations/pie_chart.js b/src/ui/public/vislib/__tests__/visualizations/pie_chart.js
index 26edaecadc6fa..3cbd29a52991f 100644
--- a/src/ui/public/vislib/__tests__/visualizations/pie_chart.js
+++ b/src/ui/public/vislib/__tests__/visualizations/pie_chart.js
@@ -11,39 +11,39 @@ import PersistedStatePersistedStateProvider from 'ui/persisted_state/persisted_s
 import FixturesStubbedLogstashIndexPatternProvider from 'fixtures/stubbed_logstash_index_pattern';
 import AggResponseHierarchicalBuildHierarchicalDataProvider from 'ui/agg_response/hierarchical/build_hierarchical_data';
 
-let rowAgg = [
+const rowAgg = [
   { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
   { type: 'terms', schema: 'split', params: { field: 'extension', rows: true }},
   { type: 'terms', schema: 'segment', params: { field: 'machine.os' }},
   { type: 'terms', schema: 'segment', params: { field: 'geo.src' }}
 ];
 
-let colAgg = [
+const colAgg = [
   { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
   { type: 'terms', schema: 'split', params: { field: 'extension', row: false }},
   { type: 'terms', schema: 'segment', params: { field: 'machine.os' }},
   { type: 'terms', schema: 'segment', params: { field: 'geo.src' }}
 ];
 
-let sliceAgg = [
+const sliceAgg = [
   { type: 'avg', schema: 'metric', params: { field: 'bytes' } },
   { type: 'terms', schema: 'segment', params: { field: 'machine.os' }},
   { type: 'terms', schema: 'segment', params: { field: 'geo.src' }}
 ];
 
-let aggArray = [
+const aggArray = [
   rowAgg,
   colAgg,
   sliceAgg
 ];
 
-let names = [
+const names = [
   'rows',
   'columns',
   'slices'
 ];
 
-let sizes = [
+const sizes = [
   0,
   5,
   15,
@@ -53,13 +53,13 @@ let sizes = [
 ];
 
 describe('No global chart settings', function () {
-  let visLibParams1 = {
+  const visLibParams1 = {
     el: '<div class=chart1></div>',
     type: 'pie',
     addLegend: true,
     addTooltip: true
   };
-  let visLibParams2 = {
+  const visLibParams2 = {
     el: '<div class=chart2></div>',
     type: 'pie',
     addLegend: true,
@@ -85,11 +85,11 @@ describe('No global chart settings', function () {
 
     let id1 = 1;
     let id2 = 1;
-    let stubVis1 = new Vis(indexPattern, {
+    const stubVis1 = new Vis(indexPattern, {
       type: 'pie',
       aggs: rowAgg
     });
-    let stubVis2 = new Vis(indexPattern, {
+    const stubVis2 = new Vis(indexPattern, {
       type: 'pie',
       aggs: colAgg
     });
@@ -120,19 +120,19 @@ describe('No global chart settings', function () {
   });
 
   describe('_validatePieData method', function () {
-    let allZeros = [
+    const allZeros = [
       { slices: { children: [] } },
       { slices: { children: [] } },
       { slices: { children: [] } }
     ];
 
-    let someZeros = [
+    const someZeros = [
       { slices: { children: [{}] } },
       { slices: { children: [{}] } },
       { slices: { children: [] } }
     ];
 
-    let noZeros = [
+    const noZeros = [
       { slices: { children: [{}] } },
       { slices: { children: [{}] } },
       { slices: { children: [{}] } }
@@ -157,7 +157,7 @@ describe('No global chart settings', function () {
 
 aggArray.forEach(function (dataAgg, i) {
   describe('Vislib PieChart Class Test Suite for ' + names[i] + ' data', function () {
-    let visLibParams = {
+    const visLibParams = {
       type: 'pie',
       addLegend: true,
       addTooltip: true
@@ -178,7 +178,7 @@ aggArray.forEach(function (dataAgg, i) {
       buildHierarchicalData = Private(AggResponseHierarchicalBuildHierarchicalDataProvider);
 
       let id = 1;
-      let stubVis = new Vis(indexPattern, {
+      const stubVis = new Vis(indexPattern, {
         type: 'pie',
         aggs: dataAgg
       });
diff --git a/src/ui/public/vislib/__tests__/visualizations/tile_maps/map.js b/src/ui/public/vislib/__tests__/visualizations/tile_maps/map.js
index b74f779c1510b..13bec5bf11477 100644
--- a/src/ui/public/vislib/__tests__/visualizations/tile_maps/map.js
+++ b/src/ui/public/vislib/__tests__/visualizations/tile_maps/map.js
@@ -25,10 +25,10 @@ import VislibVisualizationsMapProvider from 'ui/vislib/visualizations/_map';
 // ];
 
 describe('TileMap Map Tests', function () {
-  let $mockMapEl = $('<div>');
+  const $mockMapEl = $('<div>');
   let TileMapMap;
-  let leafletStubs = {};
-  let leafletMocks = {};
+  const leafletStubs = {};
+  const leafletMocks = {};
 
   beforeEach(ngMock.module('kibana'));
   beforeEach(ngMock.inject(function (Private) {
@@ -57,7 +57,7 @@ describe('TileMap Map Tests', function () {
     });
 
     it('should add zoom controls', function () {
-      let mapOptions = createStub.firstCall.args[0];
+      const mapOptions = createStub.firstCall.args[0];
 
       expect(mapOptions).to.be.an('object');
       if (mapOptions.zoomControl) expect(mapOptions.zoomControl).to.be.ok();
@@ -82,8 +82,8 @@ describe('TileMap Map Tests', function () {
       expect(leafletStubs.tileLayer.callCount).to.equal(1);
       expect(leafletStubs.map.callCount).to.equal(1);
 
-      let callArgs = leafletStubs.map.firstCall.args;
-      let mapOptions = callArgs[1];
+      const callArgs = leafletStubs.map.firstCall.args;
+      const mapOptions = callArgs[1];
       expect(callArgs[0]).to.be($mockMapEl.get(0));
       expect(mapOptions).to.have.property('zoom');
       expect(mapOptions).to.have.property('center');
@@ -122,21 +122,21 @@ describe('TileMap Map Tests', function () {
     });
 
     it('should attach interaction events', function () {
-      let expectedTileEvents = ['tileload'];
-      let expectedMapEvents = ['draw:created', 'moveend', 'zoomend', 'unload'];
-      let matchedEvents = {
+      const expectedTileEvents = ['tileload'];
+      const expectedMapEvents = ['draw:created', 'moveend', 'zoomend', 'unload'];
+      const matchedEvents = {
         tiles: 0,
         maps: 0,
       };
 
       _.times(leafletMocks.tileLayer.on.callCount, function (index) {
-        let ev = leafletMocks.tileLayer.on.getCall(index).args[0];
+        const ev = leafletMocks.tileLayer.on.getCall(index).args[0];
         if (_.includes(expectedTileEvents, ev)) matchedEvents.tiles++;
       });
       expect(matchedEvents.tiles).to.equal(expectedTileEvents.length);
 
       _.times(leafletMocks.map.on.callCount, function (index) {
-        let ev = leafletMocks.map.on.getCall(index).args[0];
+        const ev = leafletMocks.map.on.getCall(index).args[0];
         if (_.includes(expectedMapEvents, ev)) matchedEvents.maps++;
       });
       expect(matchedEvents.maps).to.equal(expectedMapEvents.length);
@@ -157,14 +157,14 @@ describe('TileMap Map Tests', function () {
     it('should pass the map options to the marker', function () {
       map._addMarkers();
 
-      let args = createStub.firstCall.args[0];
+      const args = createStub.firstCall.args[0];
       expect(args).to.have.property('tooltipFormatter');
       expect(args).to.have.property('valueFormatter');
       expect(args).to.have.property('attr');
     });
 
     it('should destroy existing markers', function () {
-      let destroyStub = sinon.stub();
+      const destroyStub = sinon.stub();
       map._markers = { destroy: destroyStub };
       map._addMarkers();
 
@@ -182,20 +182,20 @@ describe('TileMap Map Tests', function () {
 
     it('should return an empty array if no data', function () {
       map = new TileMapMap($mockMapEl, {}, {});
-      let rects = map._getDataRectangles();
+      const rects = map._getDataRectangles();
       expect(rects).to.have.length(0);
     });
 
     it('should return an array of arrays of rectangles', function () {
-      let rects = map._getDataRectangles();
+      const rects = map._getDataRectangles();
       _.times(5, function () {
-        let index = _.random(rects.length - 1);
-        let rect = rects[index];
-        let featureRect = geoJsonData.geoJson.features[index].properties.rectangle;
+        const index = _.random(rects.length - 1);
+        const rect = rects[index];
+        const featureRect = geoJsonData.geoJson.features[index].properties.rectangle;
         expect(rect.length).to.equal(featureRect.length);
 
         // should swap the array
-        let checkIndex = _.random(rect.length - 1);
+        const checkIndex = _.random(rect.length - 1);
         expect(rect[checkIndex]).to.eql(featureRect[checkIndex]);
       });
     });
diff --git a/src/ui/public/vislib/__tests__/visualizations/tile_maps/markers.js b/src/ui/public/vislib/__tests__/visualizations/tile_maps/markers.js
index 04ed6fdbea14d..8d06738695399 100644
--- a/src/ui/public/vislib/__tests__/visualizations/tile_maps/markers.js
+++ b/src/ui/public/vislib/__tests__/visualizations/tile_maps/markers.js
@@ -12,9 +12,9 @@ import VislibVisualizationsMarkerTypesShadedCirclesProvider from 'ui/vislib/visu
 import VislibVisualizationsMarkerTypesScaledCirclesProvider from 'ui/vislib/visualizations/marker_types/scaled_circles';
 import VislibVisualizationsMarkerTypesHeatmapProvider from 'ui/vislib/visualizations/marker_types/heatmap';
 // defaults to roughly the lower 48 US states
-let defaultSWCoords = [13.496, -143.789];
-let defaultNECoords = [55.526, -57.919];
-let bounds = {};
+const defaultSWCoords = [13.496, -143.789];
+const defaultNECoords = [55.526, -57.919];
+const bounds = {};
 let MarkerType;
 let map;
 
@@ -29,7 +29,7 @@ function getBounds() {
   return L.latLngBounds(bounds.southWest, bounds.northEast);
 }
 
-let mockMap = {
+const mockMap = {
   addLayer: _.noop,
   closePopup: _.noop,
   getBounds: getBounds,
@@ -76,8 +76,8 @@ describe('Marker Tests', function () {
       it('should not filter any features', function () {
         // set bounds to the entire world
         setBounds([-87.252, -343.828], [87.252, 343.125]);
-        let boundFilter = markerLayer._filterToMapBounds();
-        let mapFeature = mapData.features.filter(boundFilter);
+        const boundFilter = markerLayer._filterToMapBounds();
+        const mapFeature = mapData.features.filter(boundFilter);
 
         expect(mapFeature.length).to.equal(mapData.features.length);
       });
@@ -85,8 +85,8 @@ describe('Marker Tests', function () {
       it('should filter out data points that are outside of the map bounds', function () {
         // set bounds to roughly US southwest
         setBounds([31.690, -124.387], [42.324, -102.919]);
-        let boundFilter = markerLayer._filterToMapBounds();
-        let mapFeature = mapData.features.filter(boundFilter);
+        const boundFilter = markerLayer._filterToMapBounds();
+        const mapFeature = mapData.features.filter(boundFilter);
 
         expect(mapFeature.length).to.be.lessThan(mapData.features.length);
       });
@@ -94,8 +94,8 @@ describe('Marker Tests', function () {
 
     describe('legendQuantizer', function () {
       it('should return a range of hex colors', function () {
-        let minColor = markerLayer._legendQuantizer(mapData.properties.allmin);
-        let maxColor = markerLayer._legendQuantizer(mapData.properties.allmax);
+        const minColor = markerLayer._legendQuantizer(mapData.properties.allmin);
+        const maxColor = markerLayer._legendQuantizer(mapData.properties.allmax);
 
         expect(minColor.substring(0, 1)).to.equal('#');
         expect(minColor).to.have.length(7);
@@ -105,18 +105,18 @@ describe('Marker Tests', function () {
       });
 
       it('should return a color with 1 color', function () {
-        let geoJson = { properties: { min: 1, max: 1 } };
+        const geoJson = { properties: { min: 1, max: 1 } };
         markerLayer = createMarker(MarkerClass, geoJson);
 
         // ensure the quantizer domain is correct
-        let color = markerLayer._legendQuantizer(1);
+        const color = markerLayer._legendQuantizer(1);
         expect(color).to.not.be(undefined);
         expect(color.substring(0, 1)).to.equal('#');
 
         // should always get the same color back
         _.times(5, function () {
-          let num = _.random(0, 100);
-          let randColor = markerLayer._legendQuantizer(0);
+          const num = _.random(0, 100);
+          const randColor = markerLayer._legendQuantizer(0);
           expect(randColor).to.equal(color);
         });
       });
@@ -124,19 +124,19 @@ describe('Marker Tests', function () {
 
     describe('applyShadingStyle', function () {
       it('should return a style object', function () {
-        let style = markerLayer.applyShadingStyle(100);
+        const style = markerLayer.applyShadingStyle(100);
         expect(style).to.be.an('object');
 
-        let keys = _.keys(style);
-        let expected = ['fillColor', 'color'];
+        const keys = _.keys(style);
+        const expected = ['fillColor', 'color'];
         _.each(expected, function (key) {
           expect(keys).to.contain(key);
         });
       });
 
       it('should use the legendQuantizer', function () {
-        let spy = sinon.spy(markerLayer, '_legendQuantizer');
-        let style = markerLayer.applyShadingStyle(100);
+        const spy = sinon.spy(markerLayer, '_legendQuantizer');
+        const style = markerLayer.applyShadingStyle(100);
         expect(spy.callCount).to.equal(1);
       });
     });
@@ -144,9 +144,9 @@ describe('Marker Tests', function () {
     describe('showTooltip', function () {
       it('should use the tooltip formatter', function () {
         let content;
-        let sample = _.sample(mapData.features);
+        const sample = _.sample(mapData.features);
 
-        let stub = sinon.stub(markerLayer, '_tooltipFormatter', function (val) {
+        const stub = sinon.stub(markerLayer, '_tooltipFormatter', function (val) {
           return;
         });
 
@@ -186,12 +186,12 @@ describe('Marker Tests', function () {
       });
 
       it('should use the value formatter', function () {
-        let formatterSpy = sinon.spy(markerLayer, '_valueFormatter');
+        const formatterSpy = sinon.spy(markerLayer, '_valueFormatter');
         // called twice for every legend color defined
-        let expectedCallCount = markerLayer._legendColors.length * 2;
+        const expectedCallCount = markerLayer._legendColors.length * 2;
 
         markerLayer.addLegend();
-        let legend = markerLayer._legend.onAdd();
+        const legend = markerLayer._legend.onAdd();
 
         expect(formatterSpy.callCount).to.equal(expectedCallCount);
         expect(legend).to.be.a(HTMLDivElement);
@@ -202,14 +202,14 @@ describe('Marker Tests', function () {
   describe('Shaded Circles', function () {
     beforeEach(ngMock.module('MarkerFactory'));
     beforeEach(ngMock.inject(function (Private) {
-      let MarkerClass = Private(VislibVisualizationsMarkerTypesShadedCirclesProvider);
+      const MarkerClass = Private(VislibVisualizationsMarkerTypesShadedCirclesProvider);
       markerLayer = createMarker(MarkerClass);
     }));
 
     describe('geohashMinDistance method', function () {
       it('should return a finite number', function () {
-        let sample = _.sample(mapData.features);
-        let distance = markerLayer._geohashMinDistance(sample);
+        const sample = _.sample(mapData.features);
+        const distance = markerLayer._geohashMinDistance(sample);
 
         expect(distance).to.be.a('number');
         expect(_.isFinite(distance)).to.be(true);
@@ -224,34 +224,34 @@ describe('Marker Tests', function () {
     beforeEach(ngMock.inject(function (Private) {
       zoom = _.random(1, 18);
       sinon.stub(mockMap, 'getZoom', _.constant(zoom));
-      let MarkerClass = Private(VislibVisualizationsMarkerTypesScaledCirclesProvider);
+      const MarkerClass = Private(VislibVisualizationsMarkerTypesScaledCirclesProvider);
       markerLayer = createMarker(MarkerClass);
     }));
 
     describe('radiusScale method', function () {
-      let valueArray = [10, 20, 30, 40, 50, 60];
-      let max = _.max(valueArray);
-      let prev = -1;
+      const valueArray = [10, 20, 30, 40, 50, 60];
+      const max = _.max(valueArray);
+      const prev = -1;
 
       it('should return 0 for value of 0', function () {
         expect(markerLayer._radiusScale(0)).to.equal(0);
       });
 
       it('should return a scaled value for negative and positive numbers', function () {
-        let upperBound = markerLayer._radiusScale(max);
-        let results = [];
+        const upperBound = markerLayer._radiusScale(max);
+        const results = [];
 
         function roundValue(value) {
           // round number to 6 decimal places
-          let r = Math.pow(10, 6);
+          const r = Math.pow(10, 6);
           return Math.round(value * r) / r;
         }
 
         _.each(valueArray, function (value, i) {
-          let ratio = Math.pow(value / max, 0.5);
-          let comparison = ratio * upperBound;
-          let radius = markerLayer._radiusScale(value);
-          let negRadius = markerLayer._radiusScale(value * -1);
+          const ratio = Math.pow(value / max, 0.5);
+          const comparison = ratio * upperBound;
+          const radius = markerLayer._radiusScale(value);
+          const negRadius = markerLayer._radiusScale(value * -1);
           results.push(radius);
 
           expect(negRadius).to.equal(radius);
@@ -269,7 +269,7 @@ describe('Marker Tests', function () {
   describe('Heatmaps', function () {
     beforeEach(ngMock.module('MarkerFactory'));
     beforeEach(ngMock.inject(function (Private) {
-      let MarkerClass = Private(VislibVisualizationsMarkerTypesHeatmapProvider);
+      const MarkerClass = Private(VislibVisualizationsMarkerTypesHeatmapProvider);
       markerLayer = createMarker(MarkerClass);
     }));
 
@@ -281,7 +281,7 @@ describe('Marker Tests', function () {
       });
 
       it('should return an array or values for each feature', function () {
-        let arr = markerLayer._dataToHeatArray(max);
+        const arr = markerLayer._dataToHeatArray(max);
         expect(arr).to.be.an('array');
         expect(arr).to.have.length(mapData.features.length);
 
@@ -289,11 +289,11 @@ describe('Marker Tests', function () {
 
       it('should return an array item with lat, lng, metric for each feature', function () {
         _.times(3, function () {
-          let arr = markerLayer._dataToHeatArray(max);
-          let index = _.random(mapData.features.length - 1);
-          let feature = mapData.features[index];
-          let featureValue = feature.properties.value;
-          let featureArr = feature.geometry.coordinates.slice(0).concat(featureValue);
+          const arr = markerLayer._dataToHeatArray(max);
+          const index = _.random(mapData.features.length - 1);
+          const feature = mapData.features[index];
+          const featureValue = feature.properties.value;
+          const featureArr = feature.geometry.coordinates.slice(0).concat(featureValue);
           expect(arr[index]).to.eql(featureArr);
         });
       });
@@ -302,11 +302,11 @@ describe('Marker Tests', function () {
         _.times(5, function () {
           markerLayer._attr.heatNormalizeData = true;
 
-          let arr = markerLayer._dataToHeatArray(max);
-          let index = _.random(mapData.features.length - 1);
-          let feature = mapData.features[index];
-          let featureValue = feature.properties.value / max;
-          let featureArr = feature.geometry.coordinates.slice(0).concat(featureValue);
+          const arr = markerLayer._dataToHeatArray(max);
+          const index = _.random(mapData.features.length - 1);
+          const feature = mapData.features[index];
+          const featureValue = feature.properties.value / max;
+          const featureArr = feature.geometry.coordinates.slice(0).concat(featureValue);
           expect(arr[index]).to.eql(featureArr);
         });
       });
@@ -315,18 +315,18 @@ describe('Marker Tests', function () {
     describe('tooltipProximity', function () {
       it('should return true if feature is close enough to event latlng', function () {
         _.times(5, function () {
-          let feature = _.sample(mapData.features);
-          let point = markerLayer._getLatLng(feature);
-          let arr = markerLayer._tooltipProximity(point, feature);
+          const feature = _.sample(mapData.features);
+          const point = markerLayer._getLatLng(feature);
+          const arr = markerLayer._tooltipProximity(point, feature);
           expect(arr).to.be(true);
         });
       });
 
       it('should return false if feature is not close enough to event latlng', function () {
         _.times(5, function () {
-          let feature = _.sample(mapData.features);
-          let point = L.latLng(90, -180);
-          let arr = markerLayer._tooltipProximity(point, feature);
+          const feature = _.sample(mapData.features);
+          const point = L.latLng(90, -180);
+          const arr = markerLayer._tooltipProximity(point, feature);
           expect(arr).to.be(false);
         });
       });
@@ -335,9 +335,9 @@ describe('Marker Tests', function () {
     describe('nearestFeature', function () {
       it('should return nearest geoJson feature object', function () {
         _.times(5, function () {
-          let feature = _.sample(mapData.features);
-          let point = markerLayer._getLatLng(feature);
-          let nearestPoint = markerLayer._nearestFeature(point);
+          const feature = _.sample(mapData.features);
+          const point = markerLayer._getLatLng(feature);
+          const nearestPoint = markerLayer._nearestFeature(point);
           expect(nearestPoint).to.equal(feature);
         });
       });
@@ -345,15 +345,15 @@ describe('Marker Tests', function () {
 
     describe('getLatLng', function () {
       it('should return a leaflet latLng object', function () {
-        let feature = _.sample(mapData.features);
-        let latLng = markerLayer._getLatLng(feature);
-        let compare = L.latLng(feature.geometry.coordinates.slice(0).reverse());
+        const feature = _.sample(mapData.features);
+        const latLng = markerLayer._getLatLng(feature);
+        const compare = L.latLng(feature.geometry.coordinates.slice(0).reverse());
         expect(latLng).to.eql(compare);
       });
 
       it('should memoize the result', function () {
-        let spy = sinon.spy(L, 'latLng');
-        let feature = _.sample(mapData.features);
+        const spy = sinon.spy(L, 'latLng');
+        const feature = _.sample(mapData.features);
 
         markerLayer._getLatLng(feature);
         expect(spy.callCount).to.be(1);
diff --git a/src/ui/public/vislib/__tests__/visualizations/tile_maps/tile_map.js b/src/ui/public/vislib/__tests__/visualizations/tile_maps/tile_map.js
index 411b924265c48..0803ad328bebd 100644
--- a/src/ui/public/vislib/__tests__/visualizations/tile_maps/tile_map.js
+++ b/src/ui/public/vislib/__tests__/visualizations/tile_maps/tile_map.js
@@ -8,7 +8,7 @@ import geoJsonData from 'fixtures/vislib/mock_data/geohash/_geo_json';
 import MockMap from 'fixtures/tilemap_map';
 import $ from 'jquery';
 import VislibVisualizationsTileMapProvider from 'ui/vislib/visualizations/tile_map';
-let mockChartEl = $('<div>');
+const mockChartEl = $('<div>');
 
 let TileMap;
 let extentsStub;
@@ -18,7 +18,7 @@ function createTileMap(handler, chartEl, chartData) {
   chartEl = chartEl || mockChartEl;
   chartData = chartData || geoJsonData;
 
-  let tilemap = new TileMap(handler, chartEl, chartData);
+  const tilemap = new TileMap(handler, chartEl, chartData);
   return tilemap;
 }
 
@@ -52,7 +52,7 @@ describe('TileMap Tests', function () {
     });
 
     it('should call destroy for clean state', function () {
-      let destroySpy = sinon.spy(tilemap, 'destroy');
+      const destroySpy = sinon.spy(tilemap, 'destroy');
       tilemap.draw();
       expect(destroySpy.callCount).to.equal(1);
     });
@@ -73,14 +73,14 @@ describe('TileMap Tests', function () {
 
     it('should append maps and required controls', function () {
       expect(tilemap.maps).to.have.length(1);
-      let map = tilemap.maps[0];
+      const map = tilemap.maps[0];
       expect(map.addTitle.callCount).to.equal(0);
       expect(map.addFitControl.callCount).to.equal(1);
       expect(map.addBoundingControl.callCount).to.equal(1);
     });
 
     it('should only add controls if data exists', function () {
-      let noData = {
+      const noData = {
         geohashGridAgg: { vis: { params: {} } },
         geoJson: {
           features: [],
@@ -93,17 +93,17 @@ describe('TileMap Tests', function () {
       tilemap._appendMap($selection);
       expect(tilemap.maps).to.have.length(1);
 
-      let map = tilemap.maps[0];
+      const map = tilemap.maps[0];
       expect(map.addTitle.callCount).to.equal(0);
       expect(map.addFitControl.callCount).to.equal(0);
       expect(map.addBoundingControl.callCount).to.equal(0);
     });
 
     it('should append title if set in the data object', function () {
-      let mapTitle = 'Test Title';
+      const mapTitle = 'Test Title';
       tilemap = createTileMap(null, null, _.assign({ title: mapTitle }, geoJsonData));
       tilemap._appendMap($selection);
-      let map = tilemap.maps[0];
+      const map = tilemap.maps[0];
 
       expect(map.addTitle.callCount).to.equal(1);
       expect(map.addTitle.firstCall.calledWith(mapTitle)).to.equal(true);
@@ -111,8 +111,8 @@ describe('TileMap Tests', function () {
   });
 
   describe('destroy', function () {
-    let maps = [];
-    let mapCount = 5;
+    const maps = [];
+    const mapCount = 5;
 
     beforeEach(function () {
       _.times(mapCount, function () {
diff --git a/src/ui/public/vislib/__tests__/visualizations/time_marker.js b/src/ui/public/vislib/__tests__/visualizations/time_marker.js
index 4f13b37dfbadd..0f240cada0118 100644
--- a/src/ui/public/vislib/__tests__/visualizations/time_marker.js
+++ b/src/ui/public/vislib/__tests__/visualizations/time_marker.js
@@ -10,13 +10,13 @@ import $ from 'jquery';
 import VislibVisualizationsTimeMarkerProvider from 'ui/vislib/visualizations/time_marker';
 
 describe('Vislib Time Marker Test Suite', function () {
-  let height = 50;
-  let color = '#ff0000';
-  let opacity = 0.5;
-  let width = 3;
-  let customClass = 'custom-time-marker';
-  let dateMathTimes = ['now-1m', 'now-5m', 'now-15m'];
-  let myTimes = dateMathTimes.map(function (dateMathString) {
+  const height = 50;
+  const color = '#ff0000';
+  const opacity = 0.5;
+  const width = 3;
+  const customClass = 'custom-time-marker';
+  const dateMathTimes = ['now-1m', 'now-5m', 'now-15m'];
+  const myTimes = dateMathTimes.map(function (dateMathString) {
     return {
       time: dateMathString,
       class: customClass,
@@ -25,14 +25,14 @@ describe('Vislib Time Marker Test Suite', function () {
       width: width
     };
   });
-  let getExtent = function (dataArray, func) {
+  const getExtent = function (dataArray, func) {
     return func(dataArray, function (obj) {
       return func(obj.values, function (d) {
         return d.x;
       });
     });
   };
-  let times = [];
+  const times = [];
   let TimeMarker;
   let defaultMarker;
   let customMarker;
diff --git a/src/ui/public/vislib/components/color/color.js b/src/ui/public/vislib/components/color/color.js
index 24782c3b9ca20..3a7d4543fb7f9 100644
--- a/src/ui/public/vislib/components/color/color.js
+++ b/src/ui/public/vislib/components/color/color.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import VislibComponentsColorMappedColorsProvider from 'ui/vislib/components/color/mapped_colors';
 export default function ColorUtilService(Private) {
-  let mappedColors = Private(VislibComponentsColorMappedColorsProvider);
+  const mappedColors = Private(VislibComponentsColorMappedColorsProvider);
 
   /*
    * Accepts an array of strings or numbers that are used to create a
diff --git a/src/ui/public/vislib/components/color/color_palette.js b/src/ui/public/vislib/components/color/color_palette.js
index c380224e562f3..5b4586a2642d8 100644
--- a/src/ui/public/vislib/components/color/color_palette.js
+++ b/src/ui/public/vislib/components/color/color_palette.js
@@ -3,7 +3,7 @@ import _ from 'lodash';
 import VislibComponentsColorSeedColorsProvider from 'ui/vislib/components/color/seed_colors';
 export default function ColorPaletteUtilService(Private) {
 
-  let seedColors = Private(VislibComponentsColorSeedColorsProvider);
+  const seedColors = Private(VislibComponentsColorSeedColorsProvider);
 
 
   /*
@@ -12,10 +12,10 @@ export default function ColorPaletteUtilService(Private) {
    * new colors are generated up to the value of the input number.
    */
 
-  let offset = 300; // Hue offset to start at
+  const offset = 300; // Hue offset to start at
 
-  let fraction = function (goal) {
-    let walkTree = function (numerator, denominator, bytes) {
+  const fraction = function (goal) {
+    const walkTree = function (numerator, denominator, bytes) {
       if (bytes.length) {
         return walkTree(
           (numerator * 2) + (bytes.pop() ? 1 : -1),
@@ -28,7 +28,7 @@ export default function ColorPaletteUtilService(Private) {
       }
     };
 
-    let b = (goal + 2)
+    const b = (goal + 2)
       .toString(2)
       .split('')
       .map(function (num) {
@@ -45,9 +45,9 @@ export default function ColorPaletteUtilService(Private) {
       throw new TypeError('ColorPaletteUtilService expects a number');
     }
 
-    let colors = seedColors;
+    const colors = seedColors;
 
-    let seedLength = seedColors.length;
+    const seedLength = seedColors.length;
 
     _.times(num - seedLength, function (i) {
       colors.push(d3.hsl((fraction(i + seedLength + 1) * 360 + offset) % 360, 0.5, 0.5).toString());
diff --git a/src/ui/public/vislib/components/labels/data_array.js b/src/ui/public/vislib/components/labels/data_array.js
index 1b830826cf604..1aae7dbe9816a 100644
--- a/src/ui/public/vislib/components/labels/data_array.js
+++ b/src/ui/public/vislib/components/labels/data_array.js
@@ -1,7 +1,7 @@
 import _ from 'lodash';
 import VislibComponentsLabelsFlattenSeriesProvider from 'ui/vislib/components/labels/flatten_series';
 export default function GetArrayUtilService(Private) {
-  let flattenSeries = Private(VislibComponentsLabelsFlattenSeriesProvider);
+  const flattenSeries = Private(VislibComponentsLabelsFlattenSeriesProvider);
 
   /*
    * Accepts a Kibana data object and returns an array of values objects.
diff --git a/src/ui/public/vislib/components/labels/labels.js b/src/ui/public/vislib/components/labels/labels.js
index 72dde34576ee4..dab5a5e1486a0 100644
--- a/src/ui/public/vislib/components/labels/labels.js
+++ b/src/ui/public/vislib/components/labels/labels.js
@@ -4,9 +4,9 @@ import VislibComponentsLabelsUniqLabelsProvider from 'ui/vislib/components/label
 import VislibComponentsLabelsPiePieLabelsProvider from 'ui/vislib/components/labels/pie/pie_labels';
 export default function LabelUtilService(Private) {
 
-  let createArr = Private(VislibComponentsLabelsDataArrayProvider);
-  let getArrOfUniqLabels = Private(VislibComponentsLabelsUniqLabelsProvider);
-  let getPieLabels = Private(VislibComponentsLabelsPiePieLabelsProvider);
+  const createArr = Private(VislibComponentsLabelsDataArrayProvider);
+  const getArrOfUniqLabels = Private(VislibComponentsLabelsUniqLabelsProvider);
+  const getPieLabels = Private(VislibComponentsLabelsPiePieLabelsProvider);
 
   /*
    * Accepts a Kibana data object and returns an array of unique labels (strings).
diff --git a/src/ui/public/vislib/components/labels/pie/get_pie_names.js b/src/ui/public/vislib/components/labels/pie/get_pie_names.js
index 4d157daa7934b..22ac25a686fcf 100644
--- a/src/ui/public/vislib/components/labels/pie/get_pie_names.js
+++ b/src/ui/public/vislib/components/labels/pie/get_pie_names.js
@@ -2,10 +2,10 @@ import _ from 'lodash';
 import VislibComponentsLabelsPieReturnPieNamesProvider from 'ui/vislib/components/labels/pie/return_pie_names';
 
 export default function GetPieNames(Private) {
-  let returnNames = Private(VislibComponentsLabelsPieReturnPieNamesProvider);
+  const returnNames = Private(VislibComponentsLabelsPieReturnPieNamesProvider);
 
   return function (data, columns) {
-    let slices = data.slices;
+    const slices = data.slices;
 
     if (slices.children) {
       return _(returnNames(slices.children, 0, columns))
diff --git a/src/ui/public/vislib/components/labels/pie/pie_labels.js b/src/ui/public/vislib/components/labels/pie/pie_labels.js
index a4741102e6228..250563c6586e5 100644
--- a/src/ui/public/vislib/components/labels/pie/pie_labels.js
+++ b/src/ui/public/vislib/components/labels/pie/pie_labels.js
@@ -3,17 +3,17 @@ import VislibComponentsLabelsPieRemoveZeroSlicesProvider from 'ui/vislib/compone
 import VislibComponentsLabelsPieGetPieNamesProvider from 'ui/vislib/components/labels/pie/get_pie_names';
 
 export default function PieLabels(Private) {
-  let removeZeroSlices = Private(VislibComponentsLabelsPieRemoveZeroSlicesProvider);
-  let getNames = Private(VislibComponentsLabelsPieGetPieNamesProvider);
+  const removeZeroSlices = Private(VislibComponentsLabelsPieRemoveZeroSlicesProvider);
+  const getNames = Private(VislibComponentsLabelsPieGetPieNamesProvider);
 
   return function (obj) {
     if (!_.isObject(obj)) { throw new TypeError('PieLabel expects an object'); }
 
-    let data = obj.columns || obj.rows || [obj];
-    let names = [];
+    const data = obj.columns || obj.rows || [obj];
+    const names = [];
 
     data.forEach(function (obj) {
-      let columns = obj.raw ? obj.raw.columns : undefined;
+      const columns = obj.raw ? obj.raw.columns : undefined;
       obj.slices = removeZeroSlices(obj.slices);
 
       getNames(obj, columns).forEach(function (name) {
diff --git a/src/ui/public/vislib/components/labels/pie/return_pie_names.js b/src/ui/public/vislib/components/labels/pie/return_pie_names.js
index e62f71499222b..bb69a9542c870 100644
--- a/src/ui/public/vislib/components/labels/pie/return_pie_names.js
+++ b/src/ui/public/vislib/components/labels/pie/return_pie_names.js
@@ -1,7 +1,7 @@
 define(function () {
   return function ReturnPieNames() {
     return function returnNames(array, index, columns) {
-      let names = [];
+      const names = [];
 
       array.forEach(function (obj) {
         names.push({ key: obj.name, index: index });
diff --git a/src/ui/public/vislib/components/tooltip/__tests__/positioning.js b/src/ui/public/vislib/components/tooltip/__tests__/positioning.js
index 9edb8b45415d8..828d6c739cf93 100644
--- a/src/ui/public/vislib/components/tooltip/__tests__/positioning.js
+++ b/src/ui/public/vislib/components/tooltip/__tests__/positioning.js
@@ -6,17 +6,17 @@ import posTT from '../position_tooltip';
 
 describe('Tooltip Positioning', function () {
 
-  let positions = ['north', 'south', 'east', 'west'];
-  let bounds = ['top', 'left', 'bottom', 'right'];
+  const positions = ['north', 'south', 'east', 'west'];
+  const bounds = ['top', 'left', 'bottom', 'right'];
   let $window;
   let $chart;
   let $tooltip;
   let $sizer;
 
   function testEl(width, height, $children) {
-    let $el = $('<div>');
+    const $el = $('<div>');
 
-    let size = {
+    const size = {
       width: _.random(width[0], width[1]),
       height: _.random(height[0], height[1])
     };
@@ -57,7 +57,7 @@ describe('Tooltip Positioning', function () {
     xPercent = xPercent || 0.5;
     yPercent = yPercent || 0.5;
 
-    let base = $chart.offset();
+    const base = $chart.offset();
 
     return {
       clientX: base.left + ($chart.testSize.width * xPercent),
@@ -67,14 +67,14 @@ describe('Tooltip Positioning', function () {
 
   describe('getTtSize()', function () {
     it('should measure the outer-size of the tooltip using an un-obstructed clone', function () {
-      let w = sinon.spy($.fn, 'outerWidth');
-      let h = sinon.spy($.fn, 'outerHeight');
+      const w = sinon.spy($.fn, 'outerWidth');
+      const h = sinon.spy($.fn, 'outerHeight');
 
       posTT.getTtSize($tooltip.html(), $sizer);
 
       [w, h].forEach(function (spy) {
         expect(spy).to.have.property('callCount', 1);
-        let matchHtml = w.thisValues.filter(function ($t) {
+        const matchHtml = w.thisValues.filter(function ($t) {
           return !$t.is($tooltip) && $t.html() === $tooltip.html();
         });
         expect(matchHtml).to.have.length(1);
@@ -84,8 +84,8 @@ describe('Tooltip Positioning', function () {
 
   describe('getBasePosition()', function () {
     it('calculates the offset values for the four positions', function () {
-      let size = posTT.getTtSize($tooltip.html(), $sizer);
-      let pos = posTT.getBasePosition(size, makeEvent());
+      const size = posTT.getTtSize($tooltip.html(), $sizer);
+      const pos = posTT.getBasePosition(size, makeEvent());
 
       positions.forEach(function (p) {
         expect(pos).to.have.property(p);
@@ -98,7 +98,7 @@ describe('Tooltip Positioning', function () {
 
   describe('getBounds()', function () {
     it('returns the offsets for the tlrb of the element', function () {
-      let cbounds = posTT.getBounds($chart);
+      const cbounds = posTT.getBounds($chart);
 
       bounds.forEach(function (b) {
         expect(cbounds).to.have.property(b);
@@ -114,14 +114,14 @@ describe('Tooltip Positioning', function () {
       // size the tooltip very small so it won't collide with the edges
       $tooltip.css({ width: 15, height: 15 });
       $sizer.css({ width: 15, height: 15 });
-      let size = posTT.getTtSize($tooltip.html(), $sizer);
+      const size = posTT.getTtSize($tooltip.html(), $sizer);
       expect(size).to.have.property('width', 15);
       expect(size).to.have.property('height', 15);
 
       // position the element based on a mouse that is in the middle of the chart
-      let pos = posTT.getBasePosition(size, makeEvent(0.5, 0.5));
+      const pos = posTT.getBasePosition(size, makeEvent(0.5, 0.5));
 
-      let overflow = posTT.getOverflow(size, pos, [$chart, $window]);
+      const overflow = posTT.getOverflow(size, pos, [$chart, $window]);
       positions.forEach(function (p) {
         expect(overflow).to.have.property(p);
 
@@ -131,11 +131,11 @@ describe('Tooltip Positioning', function () {
     });
 
     it('identifies an overflow with a positive value in that direction', function () {
-      let size = posTT.getTtSize($tooltip.html(), $sizer);
+      const size = posTT.getTtSize($tooltip.html(), $sizer);
 
       // position the element based on a mouse that is in the bottom right hand courner of the chart
-      let pos = posTT.getBasePosition(size, makeEvent(0.99, 0.99));
-      let overflow = posTT.getOverflow(size, pos, [$chart, $window]);
+      const pos = posTT.getBasePosition(size, makeEvent(0.99, 0.99));
+      const overflow = posTT.getOverflow(size, pos, [$chart, $window]);
 
       positions.forEach(function (p) {
         expect(overflow).to.have.property(p);
@@ -157,9 +157,9 @@ describe('Tooltip Positioning', function () {
     });
 
     function check(xPercent, yPercent/*, prev, directions... */) {
-      let directions = _.drop(arguments, 2);
-      let event = makeEvent(xPercent, yPercent);
-      let placement = posTT({
+      const directions = _.drop(arguments, 2);
+      const event = makeEvent(xPercent, yPercent);
+      const placement = posTT({
         $window: $window,
         $chart: $chart,
         $sizer: $sizer,
@@ -214,12 +214,12 @@ describe('Tooltip Positioning', function () {
 
     describe('maintain the direction of the tooltip on reposition', function () {
       it('mouse moves from the top right to the middle', function () {
-        let pos = check(0.99, 0.10, 'bottom', 'left');
+        const pos = check(0.99, 0.10, 'bottom', 'left');
         check(0.50, 0.50, pos, 'bottom', 'left');
       });
 
       it('mouse moves from the bottom left to the middle', function () {
-        let pos = check(0.10, 0.99, 'top', 'right');
+        const pos = check(0.10, 0.99, 'top', 'right');
         check(0.50, 0.50, pos, 'top', 'right');
       });
     });
diff --git a/src/ui/public/vislib/components/tooltip/position_tooltip.js b/src/ui/public/vislib/components/tooltip/position_tooltip.js
index 14051f5c862c9..2230bf2dd771a 100644
--- a/src/ui/public/vislib/components/tooltip/position_tooltip.js
+++ b/src/ui/public/vislib/components/tooltip/position_tooltip.js
@@ -1,31 +1,31 @@
 import _ from 'lodash';
 import $ from 'jquery';
 
-let OFFSET = 10;
+const OFFSET = 10;
 let $clone;
 
 // translate css properties into their basic direction
-let propDirs = {
+const propDirs = {
   top: 'north',
   left: 'west'
 };
 
 function positionTooltip(opts, html) {
   if (!opts) return;
-  let $chart = $(opts.$chart);
-  let $el = $(opts.$el);
-  let $window = $(opts.$window || window);
-  let $sizer = $(opts.$sizer);
-  let prev = $chart.data('previousPlacement') || {};
-  let event = opts.event;
+  const $chart = $(opts.$chart);
+  const $el = $(opts.$el);
+  const $window = $(opts.$window || window);
+  const $sizer = $(opts.$sizer);
+  const prev = $chart.data('previousPlacement') || {};
+  const event = opts.event;
 
   if (!$chart.size() || !$el.size()) return;
 
-  let size = getTtSize(html || $el.html(), $sizer);
-  let pos = getBasePosition(size, event);
-  let overflow = getOverflow(size, pos, [$chart, $window]);
+  const size = getTtSize(html || $el.html(), $sizer);
+  const pos = getBasePosition(size, event);
+  const overflow = getOverflow(size, pos, [$chart, $window]);
 
-  let placement = placeToAvoidOverflow(pos, prev, overflow);
+  const placement = placeToAvoidOverflow(pos, prev, overflow);
   $chart.data('previousPlacement', placement);
   return placement;
 }
@@ -35,7 +35,7 @@ function getTtSize(ttHtml, $sizer) {
     $sizer.html(ttHtml);
   }
 
-  let size = {
+  const size = {
     width: $sizer.outerWidth(),
     height: $sizer.outerHeight()
   };
@@ -55,7 +55,7 @@ function getBasePosition(size, event) {
 function getBounds($el) {
   // in testing, $window is not actually a window, so we need to add
   // the offsets to make it work right.
-  let bounds = $el.offset() || { top: 0, left: 0 };
+  const bounds = $el.offset() || { top: 0, left: 0 };
   bounds.top += $el.scrollTop();
   bounds.left += $el.scrollLeft();
   bounds.bottom = bounds.top + $el.outerHeight();
@@ -64,7 +64,7 @@ function getBounds($el) {
 }
 
 function getOverflow(size, pos, containers) {
-  let overflow = {};
+  const overflow = {};
 
   containers.map(getBounds).forEach(function (bounds) {
     // number of pixels that the toolip would overflow it's far
@@ -90,10 +90,10 @@ function mergeOverflows(dest, src) {
 }
 
 function pickPlacement(prop, pos, overflow, prev, pref, fallback, placement) {
-  let stash = '_' + prop;
+  const stash = '_' + prop;
 
   // list of directions in order of preference
-  let dirs = _.unique([prev[stash], pref, fallback].filter(Boolean));
+  const dirs = _.unique([prev[stash], pref, fallback].filter(Boolean));
 
   let dir;
   let value;
@@ -126,7 +126,7 @@ function pickPlacement(prop, pos, overflow, prev, pref, fallback, placement) {
 }
 
 function placeToAvoidOverflow(pos, prev, overflow) {
-  let placement = {};
+  const placement = {};
   pickPlacement('top', pos, overflow, prev, 'south', 'north', placement);
   pickPlacement('left', pos, overflow, prev, 'east', 'west', placement);
   return placement;
diff --git a/src/ui/public/vislib/components/tooltip/tooltip.js b/src/ui/public/vislib/components/tooltip/tooltip.js
index 451bc5528d4a8..37a169fbfad6a 100644
--- a/src/ui/public/vislib/components/tooltip/tooltip.js
+++ b/src/ui/public/vislib/components/tooltip/tooltip.js
@@ -59,13 +59,13 @@ Tooltip.prototype.$getSizer = _.once(function () {
  * Show the tooltip, positioning it based on the content and chart container
  */
 Tooltip.prototype.show = function () {
-  let $tooltip = this.$get();
-  let $chart = this.$getChart();
-  let html = $tooltip.html();
+  const $tooltip = this.$get();
+  const $chart = this.$getChart();
+  const html = $tooltip.html();
 
   if (!$chart) return;
 
-  let placement = positionTooltip({
+  const placement = positionTooltip({
     $window: $(window),
     $chart: $chart,
     $el: $tooltip,
@@ -84,7 +84,7 @@ Tooltip.prototype.show = function () {
  * Hide the tooltip, clearing its contents
  */
 Tooltip.prototype.hide = function () {
-  let $tooltip = this.$get();
+  const $tooltip = this.$get();
   allContents = [];
   $tooltip.css({
     visibility: 'hidden',
@@ -100,7 +100,7 @@ Tooltip.prototype.hide = function () {
  * @return {Object} jQuery node for the chart
  */
 Tooltip.prototype.$getChart = function () {
-  let chart = $(this.container && this.container.node());
+  const chart = $(this.container && this.container.node());
   return chart.size() ? chart : false;
 };
 
@@ -111,7 +111,7 @@ Tooltip.prototype.$getChart = function () {
  * @return {Function} Renders tooltip on a D3 selection
  */
 Tooltip.prototype.render = function () {
-  let self = this;
+  const self = this;
 
   /**
    * Calculates values for the tooltip placement
@@ -119,17 +119,17 @@ Tooltip.prototype.render = function () {
    * @param {Object} selection D3 selection object
    */
   return function (selection) {
-    let $tooltip = self.$get();
-    let id = self.id;
-    let order = self.order;
+    const $tooltip = self.$get();
+    const id = self.id;
+    const order = self.order;
 
-    let tooltipSelection = d3.select($tooltip.get(0));
+    const tooltipSelection = d3.select($tooltip.get(0));
 
     if (self.container === undefined || self.container !== d3.select(self.el).select('.' + self.containerClass)) {
       self.container = d3.select(self.el).select('.' + self.containerClass);
     }
 
-    let $chart = self.$getChart();
+    const $chart = self.$getChart();
     if ($chart) {
       self.binder.jqOn($chart, 'mouseleave', function (event) {
         // only clear when we leave the chart, so that
@@ -139,7 +139,7 @@ Tooltip.prototype.render = function () {
     }
 
     selection.each(function (d, i) {
-      let element = d3.select(this);
+      const element = d3.select(this);
 
       function render(html) {
         allContents = _.filter(allContents, function (content) {
@@ -148,7 +148,7 @@ Tooltip.prototype.render = function () {
 
         if (html) allContents.push({ id: id, html: html, order: order });
 
-        let allHtml = _(allContents)
+        const allHtml = _(allContents)
         .sortBy('order')
         .pluck('html')
         .compact()
@@ -167,7 +167,7 @@ Tooltip.prototype.render = function () {
           return render();
         }
 
-        let events = self.events ? self.events.eventResponse(d, i) : d;
+        const events = self.events ? self.events.eventResponse(d, i) : d;
         return render(self.formatter(events));
       });
 
diff --git a/src/ui/public/vislib/components/zero_injection/inject_zeros.js b/src/ui/public/vislib/components/zero_injection/inject_zeros.js
index f738a7e424867..44479674ac987 100644
--- a/src/ui/public/vislib/components/zero_injection/inject_zeros.js
+++ b/src/ui/public/vislib/components/zero_injection/inject_zeros.js
@@ -4,9 +4,9 @@ import VislibComponentsZeroInjectionZeroFilledArrayProvider from 'ui/vislib/comp
 import VislibComponentsZeroInjectionZeroFillDataArrayProvider from 'ui/vislib/components/zero_injection/zero_fill_data_array';
 export default function ZeroInjectionUtilService(Private) {
 
-  let orderXValues = Private(VislibComponentsZeroInjectionOrderedXKeysProvider);
-  let createZeroFilledArray = Private(VislibComponentsZeroInjectionZeroFilledArrayProvider);
-  let zeroFillDataArray = Private(VislibComponentsZeroInjectionZeroFillDataArrayProvider);
+  const orderXValues = Private(VislibComponentsZeroInjectionOrderedXKeysProvider);
+  const createZeroFilledArray = Private(VislibComponentsZeroInjectionZeroFilledArrayProvider);
+  const zeroFillDataArray = Private(VislibComponentsZeroInjectionZeroFillDataArrayProvider);
 
   /*
    * A Kibana data object may have multiple series with different array lengths.
@@ -34,12 +34,12 @@ export default function ZeroInjectionUtilService(Private) {
       throw new TypeError('ZeroInjectionUtilService expects an object with a series, rows, or columns key');
     }
 
-    let keys = orderXValues(obj);
-    let arr = getDataArray(obj);
+    const keys = orderXValues(obj);
+    const arr = getDataArray(obj);
 
     arr.forEach(function (object) {
       object.series.forEach(function (series) {
-        let zeroArray = createZeroFilledArray(keys);
+        const zeroArray = createZeroFilledArray(keys);
 
         series.values = zeroFillDataArray(zeroArray, series.values);
       });
diff --git a/src/ui/public/vislib/components/zero_injection/ordered_x_keys.js b/src/ui/public/vislib/components/zero_injection/ordered_x_keys.js
index 1deab31715ec1..13afcb736d59a 100644
--- a/src/ui/public/vislib/components/zero_injection/ordered_x_keys.js
+++ b/src/ui/public/vislib/components/zero_injection/ordered_x_keys.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import moment from 'moment';
 import VislibComponentsZeroInjectionUniqKeysProvider from 'ui/vislib/components/zero_injection/uniq_keys';
 export default function OrderedXKeysUtilService(Private) {
-  let getUniqKeys = Private(VislibComponentsZeroInjectionUniqKeysProvider);
+  const getUniqKeys = Private(VislibComponentsZeroInjectionUniqKeysProvider);
 
   /*
    * Accepts a Kibana data object and returns
@@ -16,11 +16,11 @@ export default function OrderedXKeysUtilService(Private) {
       throw new Error('OrderedXKeysUtilService expects an object');
     }
 
-    let uniqKeys = getUniqKeys(obj);
-    let uniqKeysPairs = [...uniqKeys.entries()];
+    const uniqKeys = getUniqKeys(obj);
+    const uniqKeysPairs = [...uniqKeys.entries()];
 
-    let interval = _.get(obj, 'ordered.interval');
-    let dateInterval = moment.isDuration(interval) ? interval : false;
+    const interval = _.get(obj, 'ordered.interval');
+    const dateInterval = moment.isDuration(interval) ? interval : false;
 
     return _(uniqKeysPairs)
     .sortBy(function (d) {
@@ -32,13 +32,13 @@ export default function OrderedXKeysUtilService(Private) {
     .map(function (d, i, list) {
       if (!d[1].isNumber) return d[0];
 
-      let val = +d[0];
+      const val = +d[0];
       if (interval == null) return val;
 
-      let gapEdge = parseFloat(_.get(list, [i + 1, 0]));
+      const gapEdge = parseFloat(_.get(list, [i + 1, 0]));
       if (isNaN(gapEdge)) return val;
 
-      let vals = [];
+      const vals = [];
       let next = val;
 
       if (dateInterval) {
diff --git a/src/ui/public/vislib/components/zero_injection/uniq_keys.js b/src/ui/public/vislib/components/zero_injection/uniq_keys.js
index 0afe4705b579f..144a59f16f737 100644
--- a/src/ui/public/vislib/components/zero_injection/uniq_keys.js
+++ b/src/ui/public/vislib/components/zero_injection/uniq_keys.js
@@ -2,7 +2,7 @@ import _ from 'lodash';
 import VislibComponentsZeroInjectionFlattenDataProvider from 'ui/vislib/components/zero_injection/flatten_data';
 export default function UniqueXValuesUtilService(Private) {
 
-  let flattenDataArray = Private(VislibComponentsZeroInjectionFlattenDataProvider);
+  const flattenDataArray = Private(VislibComponentsZeroInjectionFlattenDataProvider);
 
   /*
    * Accepts a Kibana data object.
@@ -16,8 +16,8 @@ export default function UniqueXValuesUtilService(Private) {
       throw new TypeError('UniqueXValuesUtilService expects an object');
     }
 
-    let flattenedData = flattenDataArray(obj);
-    let uniqueXValues = new Map();
+    const flattenedData = flattenDataArray(obj);
+    const uniqueXValues = new Map();
 
     let charts;
     if (!obj.series) {
@@ -26,17 +26,17 @@ export default function UniqueXValuesUtilService(Private) {
       charts = [obj];
     }
 
-    let isDate = charts.every(function (chart) {
+    const isDate = charts.every(function (chart) {
       return chart.ordered && chart.ordered.date;
     });
 
-    let isOrdered = charts.every(function (chart) {
+    const isOrdered = charts.every(function (chart) {
       return chart.ordered;
     });
 
     flattenedData.forEach(function (d, i) {
-      let key = d.x;
-      let prev = uniqueXValues.get(key);
+      const key = d.x;
+      const prev = uniqueXValues.get(key);
 
       if (d.xi != null) {
         i = d.xi;
diff --git a/src/ui/public/vislib/components/zero_injection/zero_fill_data_array.js b/src/ui/public/vislib/components/zero_injection/zero_fill_data_array.js
index 1055e8000f6f8..e997c7d377a90 100644
--- a/src/ui/public/vislib/components/zero_injection/zero_fill_data_array.js
+++ b/src/ui/public/vislib/components/zero_injection/zero_fill_data_array.js
@@ -15,9 +15,9 @@ export default function ZeroFillDataArrayUtilService(Private) {
     let i;
     let val;
     let index;
-    let max = arr2.length;
+    const max = arr2.length;
 
-    let getX = function (d) {
+    const getX = function (d) {
       return d.x === val.x;
     };
 
diff --git a/src/ui/public/vislib/components/zero_injection/zero_filled_array.js b/src/ui/public/vislib/components/zero_injection/zero_filled_array.js
index 3a78af8065d99..ceeb4afc0c2f1 100644
--- a/src/ui/public/vislib/components/zero_injection/zero_filled_array.js
+++ b/src/ui/public/vislib/components/zero_injection/zero_filled_array.js
@@ -12,7 +12,7 @@ define(function () {
         throw new Error('ZeroFilledArrayUtilService expects an array of strings or numbers');
       }
 
-      let zeroFilledArray = [];
+      const zeroFilledArray = [];
 
       arr.forEach(function (val) {
         zeroFilledArray.push({
diff --git a/src/ui/public/vislib/lib/_error_handler.js b/src/ui/public/vislib/lib/_error_handler.js
index 3baa5da76a11d..654f0f98b5f6c 100644
--- a/src/ui/public/vislib/lib/_error_handler.js
+++ b/src/ui/public/vislib/lib/_error_handler.js
@@ -21,8 +21,8 @@ export default function ErrorHandlerFactory() {
    * @returns {HTMLElement} HTML div with an error message
    */
   ErrorHandler.prototype.validateWidthandHeight = function (width, height) {
-    let badWidth = _.isNaN(width) || width <= 0;
-    let badHeight = _.isNaN(height) || height <= 0;
+    const badWidth = _.isNaN(width) || width <= 0;
+    const badHeight = _.isNaN(height) || height <= 0;
 
     if (badWidth || badHeight) {
       throw new errors.ContainerTooSmall();
diff --git a/src/ui/public/vislib/lib/alerts.js b/src/ui/public/vislib/lib/alerts.js
index 7f44f7a9608f7..f4a1bd6d112ea 100644
--- a/src/ui/public/vislib/lib/alerts.js
+++ b/src/ui/public/vislib/lib/alerts.js
@@ -22,7 +22,7 @@ export default function AlertsFactory(Private) {
     this.alertDefs = alertDefs || [];
 
     this.binder.jqOn(vis.el, 'mouseenter', '.vis-alerts-tray', function () {
-      let $tray = $(this);
+      const $tray = $(this);
       hide();
       $(vis.el).on('mousemove', checkForExit);
 
@@ -42,13 +42,13 @@ export default function AlertsFactory(Private) {
       }
 
       function checkForExit(event) {
-        let pos = $tray.offset();
+        const pos = $tray.offset();
         if (pos.top > event.clientY || pos.left > event.clientX) return show();
 
-        let bottom = pos.top + $tray.height();
+        const bottom = pos.top + $tray.height();
         if (event.clientY > bottom) return show();
 
-        let right = pos.left + $tray.width();
+        const right = pos.left + $tray.width();
         if (event.clientX > right) return show();
       }
     });
@@ -61,21 +61,21 @@ export default function AlertsFactory(Private) {
    * @returns {D3.Selection|D3.Transition.Transition} DOM element with chart titles
    */
   Alerts.prototype.render = function () {
-    let vis = this.vis;
-    let data = this.data;
+    const vis = this.vis;
+    const data = this.data;
 
-    let alerts = _(this.alertDefs)
+    const alerts = _(this.alertDefs)
     .map(function (alertDef) {
       if (!alertDef) return;
       if (alertDef.test && !alertDef.test(vis, data)) return;
 
-      let type = alertDef.type || 'info';
-      let icon = alertDef.icon || type;
-      let msg = alertDef.msg;
+      const type = alertDef.type || 'info';
+      const icon = alertDef.icon || type;
+      const msg = alertDef.msg;
 
       // alert container
-      let $icon = $('<i>').addClass('vis-alerts-icon fa fa-' + icon);
-      let $text = $('<p>').addClass('vis-alerts-text').text(msg);
+      const $icon = $('<i>').addClass('vis-alerts-icon fa fa-' + icon);
+      const $text = $('<p>').addClass('vis-alerts-text').text(msg);
 
       return $('<div>').addClass('vis-alert vis-alert-' + type).append([$icon, $text]);
     })
diff --git a/src/ui/public/vislib/lib/axis_title.js b/src/ui/public/vislib/lib/axis_title.js
index 297f55a9be81b..98ae3e4ea4778 100644
--- a/src/ui/public/vislib/lib/axis_title.js
+++ b/src/ui/public/vislib/lib/axis_title.js
@@ -4,7 +4,7 @@ import _ from 'lodash';
 import VislibLibErrorHandlerProvider from 'ui/vislib/lib/_error_handler';
 export default function AxisTitleFactory(Private) {
 
-  let ErrorHandler = Private(VislibLibErrorHandlerProvider);
+  const ErrorHandler = Private(VislibLibErrorHandlerProvider);
 
   /**
    * Appends axis title(s) to the visualization
@@ -45,14 +45,14 @@ export default function AxisTitleFactory(Private) {
    * @returns {Function} Appends axis title to a D3 selection
    */
   AxisTitle.prototype.draw = function (title) {
-    let self = this;
+    const self = this;
 
     return function (selection) {
       selection.each(function () {
-        let el = this;
-        let div = d3.select(el);
-        let width = $(el).width();
-        let height = $(el).height();
+        const el = this;
+        const div = d3.select(el);
+        const width = $(el).width();
+        const height = $(el).height();
 
         self.validateWidthandHeight(width, height);
 
diff --git a/src/ui/public/vislib/lib/chart_title.js b/src/ui/public/vislib/lib/chart_title.js
index b0442758a8e5b..fa63d3566cab0 100644
--- a/src/ui/public/vislib/lib/chart_title.js
+++ b/src/ui/public/vislib/lib/chart_title.js
@@ -5,8 +5,8 @@ import VislibLibErrorHandlerProvider from 'ui/vislib/lib/_error_handler';
 import VislibComponentsTooltipProvider from 'ui/vislib/components/tooltip';
 export default function ChartTitleFactory(Private) {
 
-  let ErrorHandler = Private(VislibLibErrorHandlerProvider);
-  let Tooltip = Private(VislibComponentsTooltipProvider);
+  const ErrorHandler = Private(VislibLibErrorHandlerProvider);
+  const Tooltip = Private(VislibComponentsTooltipProvider);
 
   /**
    * Appends chart titles to the visualization
@@ -34,9 +34,9 @@ export default function ChartTitleFactory(Private) {
    * @returns {D3.Selection|D3.Transition.Transition} DOM element with chart titles
    */
   ChartTitle.prototype.render = function () {
-    let el = d3.select(this.el).select('.chart-title').node();
-    let width = el ? el.clientWidth : 0;
-    let height = el ? el.clientHeight : 0;
+    const el = d3.select(this.el).select('.chart-title').node();
+    const width = el ? el.clientWidth : 0;
+    const height = el ? el.clientHeight : 0;
 
     return d3.select(this.el).selectAll('.chart-title').call(this.draw(width, height));
   };
@@ -49,14 +49,14 @@ export default function ChartTitleFactory(Private) {
    * @returns {Function} Truncates text
    */
   ChartTitle.prototype.truncate = function (size) {
-    let self = this;
+    const self = this;
 
     return function (selection) {
       selection.each(function () {
-        let text = d3.select(this);
-        let n = text[0].length;
-        let maxWidth = size / n * 0.9;
-        let length = this.getComputedTextLength();
+        const text = d3.select(this);
+        const n = text[0].length;
+        const maxWidth = size / n * 0.9;
+        const length = this.getComputedTextLength();
         let str;
         let avg;
         let end;
@@ -96,14 +96,14 @@ export default function ChartTitleFactory(Private) {
    * @returns {Function} Appends chart titles to a D3 selection
    */
   ChartTitle.prototype.draw = function (width, height) {
-    let self = this;
+    const self = this;
 
     return function (selection) {
       selection.each(function () {
-        let div = d3.select(this);
-        let dataType = this.parentNode.__data__.rows ? 'rows' : 'columns';
-        let size = dataType === 'rows' ? height : width;
-        let txtHtOffset = 11;
+        const div = d3.select(this);
+        const dataType = this.parentNode.__data__.rows ? 'rows' : 'columns';
+        const size = dataType === 'rows' ? height : width;
+        const txtHtOffset = 11;
 
         self.validateWidthandHeight(width, height);
 
diff --git a/src/ui/public/vislib/lib/data.js b/src/ui/public/vislib/lib/data.js
index 5adceeb12ec45..81729605181aa 100644
--- a/src/ui/public/vislib/lib/data.js
+++ b/src/ui/public/vislib/lib/data.js
@@ -7,10 +7,10 @@ import VislibComponentsLabelsLabelsProvider from 'ui/vislib/components/labels/la
 import VislibComponentsColorColorProvider from 'ui/vislib/components/color/color';
 export default function DataFactory(Private) {
 
-  let injectZeros = Private(VislibComponentsZeroInjectionInjectZerosProvider);
-  let orderKeys = Private(VislibComponentsZeroInjectionOrderedXKeysProvider);
-  let getLabels = Private(VislibComponentsLabelsLabelsProvider);
-  let color = Private(VislibComponentsColorColorProvider);
+  const injectZeros = Private(VislibComponentsZeroInjectionInjectZerosProvider);
+  const orderKeys = Private(VislibComponentsZeroInjectionOrderedXKeysProvider);
+  const getLabels = Private(VislibComponentsLabelsLabelsProvider);
+  const color = Private(VislibComponentsColorColorProvider);
 
   /**
    * Provides an API for pulling values off the data
@@ -28,7 +28,7 @@ export default function DataFactory(Private) {
 
     this.uiState = uiState;
 
-    let self = this;
+    const self = this;
     let offset;
 
     if (attr.mode === 'stacked') {
@@ -85,7 +85,7 @@ export default function DataFactory(Private) {
 
   Data.prototype._getLabels = function (data) {
     if (this.type === 'series') {
-      let noLabel = getLabels(data).length === 1 && getLabels(data)[0] === '';
+      const noLabel = getLabels(data).length === 1 && getLabels(data)[0] === '';
       if (noLabel) {
         this._updateData();
         return [(this.get('yAxisLabel'))];
@@ -120,7 +120,7 @@ export default function DataFactory(Private) {
    * Returns the results of the addition of numbers in a filtered array.
    */
   Data.prototype._sumYs = function (arr, callback) {
-    let filteredArray = arr.filter(callback);
+    const filteredArray = arr.filter(callback);
 
     return (filteredArray.length) ? filteredArray.reduce(this._addVals) : 0;
   };
@@ -137,8 +137,8 @@ export default function DataFactory(Private) {
    *
    */
   Data.prototype._getCounts = function (i, j) {
-    let data = this.chartData();
-    let dataLengths = {};
+    const data = this.chartData();
+    const dataLengths = {};
 
     dataLengths.charts = data.length;
     dataLengths.stacks = dataLengths.charts ? data[i].series.length : 0;
@@ -151,7 +151,7 @@ export default function DataFactory(Private) {
    *
    */
   Data.prototype._createCache = function () {
-    let cache = {
+    const cache = {
       index: {
         chart: 0,
         stack: 0,
@@ -172,7 +172,7 @@ export default function DataFactory(Private) {
    * mixed datasets containing both positive and negative values.
    */
   Data.prototype._stackNegAndPosVals = function (d, y0, y) {
-    let data = this.chartData();
+    const data = this.chartData();
 
     // Storing counters and data characteristics needed to stack values properly
     if (!this._cache) {
@@ -184,7 +184,7 @@ export default function DataFactory(Private) {
 
 
     // last stack, or last value, reset the stack count and y value array
-    let lastStack = (this._cache.index.stack >= this._cache.count.stacks);
+    const lastStack = (this._cache.index.stack >= this._cache.count.stacks);
     if (lastStack) {
       this._cache.index.stack = 0;
       ++this._cache.index.value;
@@ -195,7 +195,7 @@ export default function DataFactory(Private) {
     }
 
     // last value, prepare for the next chart, if one exists
-    let lastValue = (this._cache.index.value >= this._cache.count.values);
+    const lastValue = (this._cache.index.value >= this._cache.count.values);
     if (lastValue) {
       this._cache.index.value = 0;
       ++this._cache.index.chart;
@@ -207,14 +207,14 @@ export default function DataFactory(Private) {
       }
 
       // get stack and value count for next chart
-      let chartSeries = data[this._cache.index.chart].series;
+      const chartSeries = data[this._cache.index.chart].series;
       this._cache.count.stacks = chartSeries.length;
       this._cache.count.values = chartSeries.length ? chartSeries[this._cache.index.stack].values.length : 0;
     }
   };
 
   Data.prototype.getDataType = function () {
-    let data = this.getVisData();
+    const data = this.getVisData();
     let type;
 
     data.forEach(function (obj) {
@@ -239,7 +239,7 @@ export default function DataFactory(Private) {
    */
   Data.prototype.chartData = function () {
     if (!this.data.series) {
-      let arr = this.data.rows ? this.data.rows : this.data.columns;
+      const arr = this.data.rows ? this.data.rows : this.data.columns;
       return _.toArray(arr);
     }
     return [this.data];
@@ -272,7 +272,7 @@ export default function DataFactory(Private) {
    * @return {Object}
    */
   Data.prototype.getGeoExtents = function () {
-    let visData = this.getVisData();
+    const visData = this.getVisData();
 
     return _.reduce(_.pluck(visData, 'geoJson.properties'), function (minMax, props) {
       return {
@@ -306,7 +306,7 @@ export default function DataFactory(Private) {
    * @returns {*} Data object value
    */
   Data.prototype.get = function (thing, def) {
-    let source = (this.data.rows || this.data.columns || [this.data])[0];
+    const source = (this.data.rows || this.data.columns || [this.data])[0];
     return _.get(source, thing, def);
   };
 
@@ -315,7 +315,7 @@ export default function DataFactory(Private) {
    * @returns {*}
    */
   Data.prototype.hasNullValues = function () {
-    let chartData = this.chartData();
+    const chartData = this.chartData();
 
     return chartData.some(function (chart) {
       return chart.series.some(function (obj) {
@@ -351,13 +351,13 @@ export default function DataFactory(Private) {
    * @returns {boolean}
    */
   Data.prototype.shouldBeStacked = function () {
-    let isHistogram = (this._attr.type === 'histogram');
-    let isArea = (this._attr.type === 'area');
-    let isOverlapping = (this._attr.mode === 'overlap');
-    let grouped = (this._attr.mode === 'grouped');
+    const isHistogram = (this._attr.type === 'histogram');
+    const isArea = (this._attr.type === 'area');
+    const isOverlapping = (this._attr.mode === 'overlap');
+    const grouped = (this._attr.mode === 'grouped');
 
-    let stackedHisto = isHistogram && !grouped;
-    let stackedArea = isArea && !isOverlapping;
+    const stackedHisto = isHistogram && !grouped;
+    const stackedArea = isArea && !isOverlapping;
 
     return stackedHisto || stackedArea;
   };
@@ -387,15 +387,15 @@ export default function DataFactory(Private) {
    * @returns {Number} Min y axis value
    */
   Data.prototype.getYMin = function (getValue) {
-    let self = this;
-    let arr = [];
+    const self = this;
+    const arr = [];
 
     if (this._attr.mode === 'percentage' || this._attr.mode === 'wiggle' ||
       this._attr.mode === 'silhouette') {
       return 0;
     }
 
-    let flat = this.flatten();
+    const flat = this.flatten();
     // if there is only one data point and its less than zero,
     // return 0 as the yMax value.
     if (!flat.length || flat.length === 1 && flat[0].y > 0) {
@@ -407,7 +407,7 @@ export default function DataFactory(Private) {
     // for each object in the dataArray,
     // push the calculated y value to the initialized array (arr)
     _.each(this.chartData(), function (chart) {
-      let calculatedMin = self._getYExtent(chart, 'min', getValue);
+      const calculatedMin = self._getYExtent(chart, 'min', getValue);
       if (!_.isUndefined(calculatedMin)) {
         min = Math.min(min, calculatedMin);
       }
@@ -427,14 +427,14 @@ export default function DataFactory(Private) {
    * @returns {Number} Max y axis value
    */
   Data.prototype.getYMax = function (getValue) {
-    let self = this;
-    let arr = [];
+    const self = this;
+    const arr = [];
 
     if (self._attr.mode === 'percentage') {
       return 1;
     }
 
-    let flat = this.flatten();
+    const flat = this.flatten();
     // if there is only one data point and its less than zero,
     // return 0 as the yMax value.
     if (!flat.length || flat.length === 1 && flat[0].y < 0) {
@@ -446,7 +446,7 @@ export default function DataFactory(Private) {
     // for each object in the dataArray,
     // push the calculated y value to the initialized array (arr)
     _.each(this.chartData(), function (chart) {
-      let calculatedMax = self._getYExtent(chart, 'max', getValue);
+      const calculatedMax = self._getYExtent(chart, 'max', getValue);
       if (!_.isUndefined(calculatedMax)) {
         max = Math.max(max, calculatedMax);
       }
@@ -484,7 +484,7 @@ export default function DataFactory(Private) {
       getValue = getValue || this._getY;
     }
 
-    let points = chart.series
+    const points = chart.series
     .reduce(function (points, series) {
       return points.concat(series.values);
     }, [])
@@ -519,8 +519,8 @@ export default function DataFactory(Private) {
    * @returns {Array} Array of labels (strings)
    */
   Data.prototype.returnNames = function (array, index, columns) {
-    let names = [];
-    let self = this;
+    const names = [];
+    const self = this;
 
     _.forEach(array, function (obj, i) {
       names.push({
@@ -530,7 +530,7 @@ export default function DataFactory(Private) {
       });
 
       if (obj.children) {
-        let plusIndex = index + 1;
+        const plusIndex = index + 1;
 
         _.forEach(self.returnNames(obj.children, plusIndex, columns), function (namedObj) {
           names.push(namedObj);
@@ -552,10 +552,10 @@ export default function DataFactory(Private) {
    * @returns {Array} Array of names (strings)
    */
   Data.prototype.getNames = function (data, columns) {
-    let slices = data.slices;
+    const slices = data.slices;
 
     if (slices.children) {
-      let namedObj = this.returnNames(slices.children, 0, columns);
+      const namedObj = this.returnNames(slices.children, 0, columns);
 
       return _(namedObj)
       .sortBy(function (obj) {
@@ -574,7 +574,7 @@ export default function DataFactory(Private) {
    * @returns {*}
    */
   Data.prototype._removeZeroSlices = function (slices) {
-    let self = this;
+    const self = this;
 
     if (!slices.children) return slices;
 
@@ -597,11 +597,11 @@ export default function DataFactory(Private) {
    * @returns {Array} Array of unique names (strings)
    */
   Data.prototype.pieNames = function (data) {
-    let self = this;
-    let names = [];
+    const self = this;
+    const names = [];
 
     _.forEach(data, function (obj) {
-      let columns = obj.raw ? obj.raw.columns : undefined;
+      const columns = obj.raw ? obj.raw.columns : undefined;
       obj.slices = self._removeZeroSlices(obj.slices);
 
       _.forEach(self.getNames(obj, columns), function (name) {
@@ -673,17 +673,17 @@ export default function DataFactory(Private) {
    * @return {undefined}
    */
   Data.prototype._normalizeOrdered = function () {
-    let data = this.getVisData();
-    let self = this;
+    const data = this.getVisData();
+    const self = this;
 
     data.forEach(function (d) {
       if (!d.ordered || !d.ordered.date) return;
 
-      let missingMin = d.ordered.min == null;
-      let missingMax = d.ordered.max == null;
+      const missingMin = d.ordered.min == null;
+      const missingMax = d.ordered.max == null;
 
       if (missingMax || missingMin) {
-        let extent = d3.extent(self.xValues());
+        const extent = d3.extent(self.xValues());
         if (missingMin) d.ordered.min = extent[0];
         if (missingMax) d.ordered.max = extent[1];
       }
@@ -701,11 +701,10 @@ export default function DataFactory(Private) {
    * @returns {Array} min and max values
    */
   Data.prototype.mapDataExtents = function (series) {
-    let values;
-    values = _.map(series.rows, function (row) {
+    const values = _.map(series.rows, function (row) {
       return row[row.length - 1];
     });
-    let extents = [_.min(values), _.max(values)];
+    const extents = [_.min(values), _.max(values)];
     return extents;
   };
 
diff --git a/src/ui/public/vislib/lib/dispatch.js b/src/ui/public/vislib/lib/dispatch.js
index fd2820f1a4028..9cf018242587a 100644
--- a/src/ui/public/vislib/lib/dispatch.js
+++ b/src/ui/public/vislib/lib/dispatch.js
@@ -4,7 +4,7 @@ import $ from 'jquery';
 import SimpleEmitter from 'ui/utils/simple_emitter';
 import VislibComponentsTooltipProvider from 'ui/vislib/components/tooltip';
 export default function DispatchClass(Private) {
-  let Tooltip = Private(VislibComponentsTooltipProvider);
+  const Tooltip = Private(VislibComponentsTooltipProvider);
 
   /**
    * Handles event responses
@@ -35,19 +35,19 @@ export default function DispatchClass(Private) {
    * e: (d3.event|*), handler: (Object|*)}} Event response object
    */
   Dispatch.prototype.eventResponse = function (d, i) {
-    let datum = d._input || d;
-    let data = d3.event.target.nearestViewportElement ?
+    const datum = d._input || d;
+    const data = d3.event.target.nearestViewportElement ?
       d3.event.target.nearestViewportElement.__data__ : d3.event.target.__data__;
-    let label = d.label ? d.label : d.name;
-    let isSeries = !!(data && data.series);
-    let isSlices = !!(data && data.slices);
-    let series = isSeries ? data.series : undefined;
-    let slices = isSlices ? data.slices : undefined;
-    let handler = this.handler;
-    let color = _.get(handler, 'data.color');
-    let isPercentage = (handler && handler._attr.mode === 'percentage');
-
-    let eventData = {
+    const label = d.label ? d.label : d.name;
+    const isSeries = !!(data && data.series);
+    const isSlices = !!(data && data.slices);
+    const series = isSeries ? data.series : undefined;
+    const slices = isSlices ? data.slices : undefined;
+    const handler = this.handler;
+    const color = _.get(handler, 'data.color');
+    const isPercentage = (handler && handler._attr.mode === 'percentage');
+
+    const eventData = {
       value: d.y,
       point: datum,
       datum: datum,
@@ -64,7 +64,7 @@ export default function DispatchClass(Private) {
 
     if (isSeries) {
       // Find object with the actual d value and add it to the point object
-      let object = _.find(series, { 'label': d.label });
+      const object = _.find(series, { 'label': d.label });
       eventData.value = +object.values[i].y;
 
       if (isPercentage) {
@@ -87,7 +87,7 @@ export default function DispatchClass(Private) {
   Dispatch.prototype.addEvent = function (event, callback) {
     return function (selection) {
       selection.each(function () {
-        let element = d3.select(this);
+        const element = d3.select(this);
 
         if (typeof callback === 'function') {
           return element.on(event, callback);
@@ -102,10 +102,10 @@ export default function DispatchClass(Private) {
    * @returns {Function}
    */
   Dispatch.prototype.addHoverEvent = function () {
-    let self = this;
-    let isClickable = this.listenerCount('click') > 0;
-    let addEvent = this.addEvent;
-    let $el = this.handler.el;
+    const self = this;
+    const isClickable = this.listenerCount('click') > 0;
+    const addEvent = this.addEvent;
+    const $el = this.handler.el;
     if (!this.handler.highlight) {
       this.handler.highlight = self.highlight;
     }
@@ -129,9 +129,9 @@ export default function DispatchClass(Private) {
    * @returns {Function}
    */
   Dispatch.prototype.addMouseoutEvent = function () {
-    let self = this;
-    let addEvent = this.addEvent;
-    let $el = this.handler.el;
+    const self = this;
+    const addEvent = this.addEvent;
+    const $el = this.handler.el;
     if (!this.handler.unHighlight) {
       this.handler.unHighlight = self.unHighlight;
     }
@@ -149,8 +149,8 @@ export default function DispatchClass(Private) {
    * @returns {Function}
    */
   Dispatch.prototype.addClickEvent = function () {
-    let self = this;
-    let addEvent = this.addEvent;
+    const self = this;
+    const addEvent = this.addEvent;
 
     function click(d, i) {
       self.emit('click', self.eventResponse(d, i));
@@ -166,9 +166,9 @@ export default function DispatchClass(Private) {
    * @returns {Boolean}
    */
   Dispatch.prototype.allowBrushing = function () {
-    let xAxis = this.handler.xAxis;
+    const xAxis = this.handler.xAxis;
     // Don't allow brushing for time based charts from non-time-based indices
-    let hasTimeField = this.handler.vis._attr.hasTimeField;
+    const hasTimeField = this.handler.vis._attr.hasTimeField;
 
     return Boolean(hasTimeField && xAxis.ordered && xAxis.xScale && _.isFunction(xAxis.xScale.invert));
   };
@@ -191,16 +191,16 @@ export default function DispatchClass(Private) {
   Dispatch.prototype.addBrushEvent = function (svg) {
     if (!this.isBrushable()) return;
 
-    let xScale = this.handler.xAxis.xScale;
-    let yScale = this.handler.xAxis.yScale;
-    let brush = this.createBrush(xScale, svg);
+    const xScale = this.handler.xAxis.xScale;
+    const yScale = this.handler.xAxis.yScale;
+    const brush = this.createBrush(xScale, svg);
 
     function brushEnd() {
       if (!validBrushClick(d3.event)) return;
 
-      let bar = d3.select(this);
-      let startX = d3.mouse(svg.node());
-      let startXInv = xScale.invert(startX[0]);
+      const bar = d3.select(this);
+      const startX = d3.mouse(svg.node());
+      const startXInv = xScale.invert(startX[0]);
 
       // Reset the brush value
       brush.extent([startXInv, startXInv]);
@@ -234,7 +234,7 @@ export default function DispatchClass(Private) {
    * @method highlight
    */
   Dispatch.prototype.highlight = function (element) {
-    let label = this.getAttribute('data-label');
+    const label = this.getAttribute('data-label');
     if (!label) return;
     //Opacity 1 is needed to avoid the css application
     $('[data-label]', element.parentNode).css('opacity', 1).not(
@@ -260,26 +260,26 @@ export default function DispatchClass(Private) {
    * @returns {*} Returns a D3 brush function and a SVG with a brush group attached
    */
   Dispatch.prototype.createBrush = function (xScale, svg) {
-    let self = this;
-    let attr = self.handler._attr;
-    let height = attr.height;
-    let margin = attr.margin;
+    const self = this;
+    const attr = self.handler._attr;
+    const height = attr.height;
+    const margin = attr.margin;
 
     // Brush scale
-    let brush = d3.svg.brush()
+    const brush = d3.svg.brush()
     .x(xScale)
     .on('brushend', function brushEnd() {
 
       // Assumes data is selected at the chart level
       // In this case, the number of data objects should always be 1
-      let data = d3.select(this).data()[0];
-      let isTimeSeries = (data.ordered && data.ordered.date);
+      const data = d3.select(this).data()[0];
+      const isTimeSeries = (data.ordered && data.ordered.date);
 
       // Allows for brushing on d3.scale.ordinal()
-      let selected = xScale.domain().filter(function (d) {
+      const selected = xScale.domain().filter(function (d) {
         return (brush.extent()[0] <= xScale(d)) && (xScale(d) <= brush.extent()[1]);
       });
-      let range = isTimeSeries ? brush.extent() : selected;
+      const range = isTimeSeries ? brush.extent() : selected;
 
       return self.emit('brush', {
         range: range,
@@ -296,7 +296,7 @@ export default function DispatchClass(Private) {
       .call(brush)
       .call(function (brushG) {
         // hijack the brush start event to filter out right/middle clicks
-        let brushHandler = brushG.on('mousedown.brush');
+        const brushHandler = brushG.on('mousedown.brush');
         if (!brushHandler) return; // touch events in use
         brushG.on('mousedown.brush', function () {
           if (validBrushClick(d3.event)) brushHandler.apply(this, arguments);
diff --git a/src/ui/public/vislib/lib/handler/handler.js b/src/ui/public/vislib/lib/handler/handler.js
index a74c627931860..297d402b9ed3a 100644
--- a/src/ui/public/vislib/lib/handler/handler.js
+++ b/src/ui/public/vislib/lib/handler/handler.js
@@ -6,8 +6,8 @@ import VislibLibDataProvider from 'ui/vislib/lib/data';
 import VislibLibLayoutLayoutProvider from 'ui/vislib/lib/layout/layout';
 export default function HandlerBaseClass(Private) {
 
-  let Data = Private(VislibLibDataProvider);
-  let Layout = Private(VislibLibLayoutLayoutProvider);
+  const Data = Private(VislibLibDataProvider);
+  const Layout = Private(VislibLibLayoutLayoutProvider);
 
   /**
    * Handles building all the components of the visualization
@@ -53,7 +53,7 @@ export default function HandlerBaseClass(Private) {
     // memoize so that the same function is returned every time,
     // allowing us to remove/re-add the same function
     this.getProxyHandler = _.memoize(function (event) {
-      let self = this;
+      const self = this;
       return function (e) {
         self.vis.emit(event, e);
       };
@@ -68,7 +68,7 @@ export default function HandlerBaseClass(Private) {
    * @private
    */
   Handler.prototype._validateData = function () {
-    let dataType = this.data.type;
+    const dataType = this.data.type;
 
     if (!dataType) {
       throw new errors.NoResults();
@@ -83,9 +83,9 @@ export default function HandlerBaseClass(Private) {
    * @returns {HTMLElement} With the visualization child element
    */
   Handler.prototype.render = function () {
-    let self = this;
-    let charts = this.charts = [];
-    let selection = d3.select(this.el);
+    const self = this;
+    const charts = this.charts = [];
+    const selection = d3.select(this.el);
 
     selection.selectAll('*').remove();
 
@@ -99,7 +99,7 @@ export default function HandlerBaseClass(Private) {
     // render the chart(s)
     selection.selectAll('.chart')
     .each(function (chartData) {
-      let chart = new self.ChartClass(self, this, chartData);
+      const chart = new self.ChartClass(self, this, chartData);
 
       self.vis.activeEvents().forEach(function (event) {
         self.enable(event, chart);
@@ -135,7 +135,7 @@ export default function HandlerBaseClass(Private) {
 
   function chartEventProxyToggle(method) {
     return function (event, chart) {
-      let proxyHandler = this.getProxyHandler(event);
+      const proxyHandler = this.getProxyHandler(event);
 
       _.each(chart ? [chart] : this.charts, function (chart) {
         chart.events[method](event, proxyHandler);
@@ -166,7 +166,7 @@ export default function HandlerBaseClass(Private) {
   Handler.prototype.error = function (message) {
     this.removeAll(this.el);
 
-    let div = d3.select(this.el)
+    const div = d3.select(this.el)
     .append('div')
     // class name needs `chart` in it for the polling checkSize function
     // to continuously call render on resize
diff --git a/src/ui/public/vislib/lib/handler/handler_types.js b/src/ui/public/vislib/lib/handler/handler_types.js
index 3034bef76e5cc..5473181a97f68 100644
--- a/src/ui/public/vislib/lib/handler/handler_types.js
+++ b/src/ui/public/vislib/lib/handler/handler_types.js
@@ -3,7 +3,7 @@ import VislibLibHandlerTypesPieProvider from 'ui/vislib/lib/handler/types/pie';
 import VislibLibHandlerTypesTileMapProvider from 'ui/vislib/lib/handler/types/tile_map';
 
 export default function HandlerTypeFactory(Private) {
-  let pointSeries = Private(VislibLibHandlerTypesPointSeriesProvider);
+  const pointSeries = Private(VislibLibHandlerTypesPointSeriesProvider);
 
   /**
    * Handles the building of each visualization
diff --git a/src/ui/public/vislib/lib/handler/types/pie.js b/src/ui/public/vislib/lib/handler/types/pie.js
index c5ff5042855a2..32d41221cbc7a 100644
--- a/src/ui/public/vislib/lib/handler/types/pie.js
+++ b/src/ui/public/vislib/lib/handler/types/pie.js
@@ -3,9 +3,9 @@ import VislibLibDataProvider from 'ui/vislib/lib/data';
 import VislibLibChartTitleProvider from 'ui/vislib/lib/chart_title';
 
 export default function PieHandler(Private) {
-  let Handler = Private(VislibLibHandlerHandlerProvider);
-  let Data = Private(VislibLibDataProvider);
-  let ChartTitle = Private(VislibLibChartTitleProvider);
+  const Handler = Private(VislibLibHandlerHandlerProvider);
+  const Data = Private(VislibLibDataProvider);
+  const ChartTitle = Private(VislibLibChartTitleProvider);
 
   /*
    * Handler for Pie visualizations.
diff --git a/src/ui/public/vislib/lib/handler/types/point_series.js b/src/ui/public/vislib/lib/handler/types/point_series.js
index 3e1f1d3aa070b..71ef450f0fe92 100644
--- a/src/ui/public/vislib/lib/handler/types/point_series.js
+++ b/src/ui/public/vislib/lib/handler/types/point_series.js
@@ -8,14 +8,14 @@ import VislibLibChartTitleProvider from 'ui/vislib/lib/chart_title';
 import VislibLibAlertsProvider from 'ui/vislib/lib/alerts';
 
 export default function ColumnHandler(Private) {
-  let injectZeros = Private(VislibComponentsZeroInjectionInjectZerosProvider);
-  let Handler = Private(VislibLibHandlerHandlerProvider);
-  let Data = Private(VislibLibDataProvider);
-  let XAxis = Private(VislibLibXAxisProvider);
-  let YAxis = Private(VislibLibYAxisProvider);
-  let AxisTitle = Private(VislibLibAxisTitleProvider);
-  let ChartTitle = Private(VislibLibChartTitleProvider);
-  let Alerts = Private(VislibLibAlertsProvider);
+  const injectZeros = Private(VislibComponentsZeroInjectionInjectZerosProvider);
+  const Handler = Private(VislibLibHandlerHandlerProvider);
+  const Data = Private(VislibLibDataProvider);
+  const XAxis = Private(VislibLibXAxisProvider);
+  const YAxis = Private(VislibLibYAxisProvider);
+  const AxisTitle = Private(VislibLibAxisTitleProvider);
+  const ChartTitle = Private(VislibLibChartTitleProvider);
+  const Alerts = Private(VislibLibAlertsProvider);
 
   /*
    * Create handlers for Area, Column, and Line charts which
@@ -25,7 +25,7 @@ export default function ColumnHandler(Private) {
     opts = opts || {};
 
     return function (vis) {
-      let isUserDefinedYAxis = vis._attr.setYExtents;
+      const isUserDefinedYAxis = vis._attr.setYExtents;
       let data;
 
       if (opts.zeroFill) {
@@ -78,8 +78,8 @@ export default function ColumnHandler(Private) {
           test: function (vis, data) {
             if (!data.shouldBeStacked() || data.maxNumberOfSeries() < 2) return;
 
-            let hasPos = data.getYMax(data._getY) > 0;
-            let hasNeg = data.getYMin(data._getY) < 0;
+            const hasPos = data.getYMax(data._getY) > 0;
+            const hasNeg = data.getYMin(data._getY) < 0;
             return (hasPos && hasNeg);
           }
         },
diff --git a/src/ui/public/vislib/lib/handler/types/tile_map.js b/src/ui/public/vislib/lib/handler/types/tile_map.js
index 60609c5349d9b..c95496e0596b0 100644
--- a/src/ui/public/vislib/lib/handler/types/tile_map.js
+++ b/src/ui/public/vislib/lib/handler/types/tile_map.js
@@ -3,13 +3,13 @@ import VislibLibHandlerHandlerProvider from 'ui/vislib/lib/handler/handler';
 import VislibLibDataProvider from 'ui/vislib/lib/data';
 export default function MapHandlerProvider(Private) {
 
-  let Handler = Private(VislibLibHandlerHandlerProvider);
-  let Data = Private(VislibLibDataProvider);
+  const Handler = Private(VislibLibHandlerHandlerProvider);
+  const Data = Private(VislibLibDataProvider);
 
   return function (vis) {
-    let data = new Data(vis.data, vis._attr, vis.uiState);
+    const data = new Data(vis.data, vis._attr, vis.uiState);
 
-    let MapHandler = new Handler(vis, {
+    const MapHandler = new Handler(vis, {
       data: data
     });
 
diff --git a/src/ui/public/vislib/lib/layout/layout.js b/src/ui/public/vislib/lib/layout/layout.js
index e0141dc71ce53..a749129939e42 100644
--- a/src/ui/public/vislib/lib/layout/layout.js
+++ b/src/ui/public/vislib/lib/layout/layout.js
@@ -3,7 +3,7 @@ import _ from 'lodash';
 import VislibLibLayoutLayoutTypesProvider from 'ui/vislib/lib/layout/layout_types';
 export default function LayoutFactory(Private) {
 
-  let layoutType = Private(VislibLibLayoutLayoutTypesProvider);
+  const layoutType = Private(VislibLibLayoutLayoutTypesProvider);
 
   /**
    * Builds the visualization DOM layout
@@ -53,7 +53,7 @@ export default function LayoutFactory(Private) {
    * @returns {*} Creates the visualization layout
    */
   Layout.prototype.createLayout = function (arr) {
-    let self = this;
+    const self = this;
 
     return _.each(arr, function (obj) {
       self.layout(obj);
@@ -86,7 +86,7 @@ export default function LayoutFactory(Private) {
       obj.parent = '.' + obj.parent;
     }
 
-    let childEl = this.appendElem(obj.parent, obj.type, obj.class);
+    const childEl = this.appendElem(obj.parent, obj.type, obj.class);
 
     if (obj.datum) {
       childEl.datum(obj.datum);
@@ -97,7 +97,7 @@ export default function LayoutFactory(Private) {
     }
 
     if (obj.children) {
-      let newParent = childEl[0][0];
+      const newParent = childEl[0][0];
 
       _.forEach(obj.children, function (obj) {
         if (!obj.parent) {
diff --git a/src/ui/public/vislib/lib/layout/splits/column_chart/chart_split.js b/src/ui/public/vislib/lib/layout/splits/column_chart/chart_split.js
index 80f0b09651b6c..f32fc7a3ce364 100644
--- a/src/ui/public/vislib/lib/layout/splits/column_chart/chart_split.js
+++ b/src/ui/public/vislib/lib/layout/splits/column_chart/chart_split.js
@@ -9,7 +9,7 @@ define(function () {
      */
     return function split(selection) {
       selection.each(function (data) {
-        let div = d3.select(this)
+        const div = d3.select(this)
         .attr('class', function () {
           if (data.rows) {
             return 'chart-wrapper-row';
@@ -21,7 +21,7 @@ define(function () {
         });
         let divClass;
 
-        let charts = div.selectAll('charts')
+        const charts = div.selectAll('charts')
         .append('div')
         .data(function (d) {
           if (d.rows) {
diff --git a/src/ui/public/vislib/lib/layout/splits/column_chart/chart_title_split.js b/src/ui/public/vislib/lib/layout/splits/column_chart/chart_title_split.js
index a6f1860b5b31c..6b35891c9f7b5 100644
--- a/src/ui/public/vislib/lib/layout/splits/column_chart/chart_title_split.js
+++ b/src/ui/public/vislib/lib/layout/splits/column_chart/chart_title_split.js
@@ -13,11 +13,11 @@ define(function () {
      */
     return function (selection) {
       selection.each(function (data) {
-        let div = d3.select(this);
-        let parent = $(this).parents('.vis-wrapper');
+        const div = d3.select(this);
+        const parent = $(this).parents('.vis-wrapper');
 
         if (!data.series) {
-          let splits = div.selectAll('.chart-title')
+          const splits = div.selectAll('.chart-title')
           .data(function (d) {
             return d.rows ? d.rows : d.columns;
           })
diff --git a/src/ui/public/vislib/lib/layout/splits/column_chart/x_axis_split.js b/src/ui/public/vislib/lib/layout/splits/column_chart/x_axis_split.js
index a827e50ad672e..2d99d4bbd25bc 100644
--- a/src/ui/public/vislib/lib/layout/splits/column_chart/x_axis_split.js
+++ b/src/ui/public/vislib/lib/layout/splits/column_chart/x_axis_split.js
@@ -10,7 +10,7 @@ define(function () {
 
     return function (selection) {
       selection.each(function () {
-        let div = d3.select(this);
+        const div = d3.select(this);
 
         div.selectAll('.x-axis-div')
         .append('div')
diff --git a/src/ui/public/vislib/lib/layout/splits/column_chart/y_axis_split.js b/src/ui/public/vislib/lib/layout/splits/column_chart/y_axis_split.js
index 797e681075aab..93d8188073a18 100644
--- a/src/ui/public/vislib/lib/layout/splits/column_chart/y_axis_split.js
+++ b/src/ui/public/vislib/lib/layout/splits/column_chart/y_axis_split.js
@@ -10,10 +10,10 @@ define(function () {
 
     // render and get bounding box width
     return function (selection, parent, opts) {
-      let yAxis = opts && opts.yAxis;
+      const yAxis = opts && opts.yAxis;
 
       selection.each(function () {
-        let div = d3.select(this);
+        const div = d3.select(this);
 
         div.call(setWidth, yAxis);
 
@@ -31,14 +31,14 @@ define(function () {
     function setWidth(el, yAxis) {
       if (!yAxis) return;
 
-      let padding = 5;
-      let height = parseInt(el.node().clientHeight, 10);
+      const padding = 5;
+      const height = parseInt(el.node().clientHeight, 10);
 
       // render svg and get the width of the bounding box
-      let svg = d3.select('body')
+      const svg = d3.select('body')
       .append('svg')
       .attr('style', 'position:absolute; top:-10000; left:-10000');
-      let width = svg.append('g')
+      const width = svg.append('g')
       .call(yAxis.getYAxis(height)).node().getBBox().width + padding;
       svg.remove();
 
diff --git a/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_split.js b/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_split.js
index 445a4ffb1e369..af58177503590 100644
--- a/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_split.js
+++ b/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_split.js
@@ -10,7 +10,7 @@ define(function () {
 
     return function split(selection) {
       selection.each(function (data) {
-        let div = d3.select(this)
+        const div = d3.select(this)
         .attr('class', function () {
           if (data.rows) {
             return 'chart-wrapper-row';
@@ -22,7 +22,7 @@ define(function () {
         });
         let divClass;
 
-        let charts = div.selectAll('charts')
+        const charts = div.selectAll('charts')
         .append('div')
         .data(function (d) {
           if (d.rows) {
diff --git a/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_title_split.js b/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_title_split.js
index dd07c5e70180e..d9c70f5ddff44 100644
--- a/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_title_split.js
+++ b/src/ui/public/vislib/lib/layout/splits/pie_chart/chart_title_split.js
@@ -12,7 +12,7 @@ define(function () {
 
     return function (selection, parent) {
       selection.each(function (data) {
-        let div = d3.select(this);
+        const div = d3.select(this);
 
         if (!data.slices) {
           div.selectAll('.chart-title')
diff --git a/src/ui/public/vislib/lib/layout/splits/tile_map/map_split.js b/src/ui/public/vislib/lib/layout/splits/tile_map/map_split.js
index 7e8116968b246..710c77083927a 100644
--- a/src/ui/public/vislib/lib/layout/splits/tile_map/map_split.js
+++ b/src/ui/public/vislib/lib/layout/splits/tile_map/map_split.js
@@ -9,7 +9,7 @@ define(function () {
      */
     return function split(selection) {
       selection.each(function (data) {
-        let div = d3.select(this)
+        const div = d3.select(this)
           .attr('class', function () {
             // Determine the parent class
             if (data.rows) {
@@ -22,7 +22,7 @@ define(function () {
           });
         let divClass;
 
-        let charts = div.selectAll('charts')
+        const charts = div.selectAll('charts')
           .append('div')
           .data(function (d) {
             // Determine the child class
diff --git a/src/ui/public/vislib/lib/layout/types/column_layout.js b/src/ui/public/vislib/lib/layout/types/column_layout.js
index 04062740841f2..b97d7b1e4ef61 100644
--- a/src/ui/public/vislib/lib/layout/types/column_layout.js
+++ b/src/ui/public/vislib/lib/layout/types/column_layout.js
@@ -5,10 +5,10 @@ import VislibLibLayoutSplitsColumnChartXAxisSplitProvider from 'ui/vislib/lib/la
 import VislibLibLayoutSplitsColumnChartChartTitleSplitProvider from 'ui/vislib/lib/layout/splits/column_chart/chart_title_split';
 export default function ColumnLayoutFactory(Private) {
 
-  let chartSplit = Private(VislibLibLayoutSplitsColumnChartChartSplitProvider);
-  let yAxisSplit = Private(VislibLibLayoutSplitsColumnChartYAxisSplitProvider);
-  let xAxisSplit = Private(VislibLibLayoutSplitsColumnChartXAxisSplitProvider);
-  let chartTitleSplit = Private(VislibLibLayoutSplitsColumnChartChartTitleSplitProvider);
+  const chartSplit = Private(VislibLibLayoutSplitsColumnChartChartSplitProvider);
+  const yAxisSplit = Private(VislibLibLayoutSplitsColumnChartYAxisSplitProvider);
+  const xAxisSplit = Private(VislibLibLayoutSplitsColumnChartXAxisSplitProvider);
+  const chartTitleSplit = Private(VislibLibLayoutSplitsColumnChartChartTitleSplitProvider);
 
   /**
    * Specifies the visualization layout for column charts.
diff --git a/src/ui/public/vislib/lib/layout/types/map_layout.js b/src/ui/public/vislib/lib/layout/types/map_layout.js
index c6f9e1e3bbc00..6327b5a08dcab 100644
--- a/src/ui/public/vislib/lib/layout/types/map_layout.js
+++ b/src/ui/public/vislib/lib/layout/types/map_layout.js
@@ -1,7 +1,7 @@
 import d3 from 'd3';
 import VislibLibLayoutSplitsTileMapMapSplitProvider from 'ui/vislib/lib/layout/splits/tile_map/map_split';
 export default function ColumnLayoutFactory(Private) {
-  let mapSplit = Private(VislibLibLayoutSplitsTileMapMapSplitProvider);
+  const mapSplit = Private(VislibLibLayoutSplitsTileMapMapSplitProvider);
 
   /*
    * Specifies the visualization layout for tile maps.
diff --git a/src/ui/public/vislib/lib/layout/types/pie_layout.js b/src/ui/public/vislib/lib/layout/types/pie_layout.js
index cb0266ec1f922..7c745d9137355 100644
--- a/src/ui/public/vislib/lib/layout/types/pie_layout.js
+++ b/src/ui/public/vislib/lib/layout/types/pie_layout.js
@@ -2,8 +2,8 @@ import d3 from 'd3';
 import VislibLibLayoutSplitsPieChartChartSplitProvider from 'ui/vislib/lib/layout/splits/pie_chart/chart_split';
 import VislibLibLayoutSplitsPieChartChartTitleSplitProvider from 'ui/vislib/lib/layout/splits/pie_chart/chart_title_split';
 export default function ColumnLayoutFactory(Private) {
-  let chartSplit = Private(VislibLibLayoutSplitsPieChartChartSplitProvider);
-  let chartTitleSplit = Private(VislibLibLayoutSplitsPieChartChartTitleSplitProvider);
+  const chartSplit = Private(VislibLibLayoutSplitsPieChartChartSplitProvider);
+  const chartTitleSplit = Private(VislibLibLayoutSplitsPieChartChartTitleSplitProvider);
 
   /**
    * Specifies the visualization layout for column charts.
diff --git a/src/ui/public/vislib/lib/resize_checker.js b/src/ui/public/vislib/lib/resize_checker.js
index fcd7e0d78948b..10b7ff86a4c6f 100644
--- a/src/ui/public/vislib/lib/resize_checker.js
+++ b/src/ui/public/vislib/lib/resize_checker.js
@@ -5,10 +5,10 @@ import EventsProvider from 'ui/events';
 import ReflowWatcherProvider from 'ui/reflow_watcher';
 export default function ResizeCheckerFactory(Private, Notifier, $rootScope) {
 
-  let EventEmitter = Private(EventsProvider);
-  let reflowWatcher = Private(ReflowWatcherProvider);
+  const EventEmitter = Private(EventsProvider);
+  const reflowWatcher = Private(ReflowWatcherProvider);
 
-  let SCHEDULE = ResizeChecker.SCHEDULE = sequencer.createEaseIn(
+  const SCHEDULE = ResizeChecker.SCHEDULE = sequencer.createEaseIn(
     100,      // shortest delay
     10000,  // longest delay
     50     // tick count
@@ -16,7 +16,7 @@ export default function ResizeCheckerFactory(Private, Notifier, $rootScope) {
 
   // maximum ms that we can delay emitting 'resize'. This is only used
   // to debounce resizes when the size of the element is constantly changing
-  let MS_MAX_RESIZE_DELAY = ResizeChecker.MS_MAX_RESIZE_DELAY = 500;
+  const MS_MAX_RESIZE_DELAY = ResizeChecker.MS_MAX_RESIZE_DELAY = 500;
 
   /**
    * Checks the size of an element on a regular basis. Provides
@@ -88,7 +88,7 @@ export default function ResizeCheckerFactory(Private, Notifier, $rootScope) {
    * @return {boolean} - true if the passed in value matches the saved size
    */
   ResizeChecker.prototype._equalsSavedSize = function (a) {
-    let b = this._savedSize || {};
+    const b = this._savedSize || {};
     return a.w === b.w && a.h === b.h;
   };
 
@@ -129,12 +129,12 @@ export default function ResizeCheckerFactory(Private, Notifier, $rootScope) {
    * @return {void}
    */
   ResizeChecker.prototype.check = function () {
-    let newSize = this.read();
-    let dirty = this.saveSize(newSize);
-    let dirtyChanged = this.saveDirty(dirty);
+    const newSize = this.read();
+    const dirty = this.saveSize(newSize);
+    const dirtyChanged = this.saveDirty(dirty);
 
-    let doneDirty = !dirty && dirtyChanged;
-    let muchDirty = dirty && (this.lastDirtyChange() - Date.now() > MS_MAX_RESIZE_DELAY);
+    const doneDirty = !dirty && dirtyChanged;
+    const muchDirty = dirty && (this.lastDirtyChange() - Date.now() > MS_MAX_RESIZE_DELAY);
     if (doneDirty || muchDirty) {
       this.emit('resize', newSize);
     }
@@ -175,10 +175,10 @@ export default function ResizeCheckerFactory(Private, Notifier, $rootScope) {
       this._tick += 1;
     }
 
-    let check = this.check; // already bound
-    let tick = this._tick;
-    let notify = this.notify;
-    let ms = this._currentSchedule[this._tick];
+    const check = this.check; // already bound
+    const tick = this._tick;
+    const notify = this.notify;
+    const ms = this._currentSchedule[this._tick];
     return (this._timerId = setTimeout(function () {
       check();
     }, ms));
diff --git a/src/ui/public/vislib/lib/x_axis.js b/src/ui/public/vislib/lib/x_axis.js
index 5e71a38e2e541..d22eb2b1ec023 100644
--- a/src/ui/public/vislib/lib/x_axis.js
+++ b/src/ui/public/vislib/lib/x_axis.js
@@ -5,7 +5,7 @@ import moment from 'moment';
 import VislibLibErrorHandlerProvider from 'ui/vislib/lib/_error_handler';
 export default function XAxisFactory(Private) {
 
-  let ErrorHandler = Private(VislibLibErrorHandlerProvider);
+  const ErrorHandler = Private(VislibLibErrorHandlerProvider);
 
   /**
    * Adds an x axis to the visualization
@@ -47,7 +47,7 @@ export default function XAxisFactory(Private) {
    * @returns {*} D3 scale function
    */
   XAxis.prototype.getScale = function () {
-    let ordered = this.ordered;
+    const ordered = this.ordered;
 
     if (ordered && ordered.date) {
       return d3.time.scale.utc();
@@ -65,7 +65,7 @@ export default function XAxisFactory(Private) {
    * @returns {*} D3 scale function
    */
   XAxis.prototype.getDomain = function (scale) {
-    let ordered = this.ordered;
+    const ordered = this.ordered;
 
     if (ordered && ordered.date) {
       return this.getTimeDomain(scale, this.xValues);
@@ -99,8 +99,8 @@ export default function XAxisFactory(Private) {
    * @param extent
    */
   XAxis.prototype._calculateExtent = function (data, extent) {
-    let ordered = this.ordered;
-    let opts = [ordered[extent]];
+    const ordered = this.ordered;
+    const opts = [ordered[extent]];
 
     let point = d3[extent](data);
     if (this.expandLastBucket && extent === 'max') {
@@ -146,17 +146,17 @@ export default function XAxisFactory(Private) {
    * @returns {number} - x + n intervals
    */
   XAxis.prototype.modByInterval = function (x, n) {
-    let ordered = this.ordered;
+    const ordered = this.ordered;
     if (!ordered) return x;
-    let interval = ordered.interval;
+    const interval = ordered.interval;
     if (!interval) return x;
 
     if (!ordered.date) {
       return x += (ordered.interval * n);
     }
 
-    let y = moment(x);
-    let method = n > 0 ? 'add' : 'subtract';
+    const y = moment(x);
+    const method = n > 0 ? 'add' : 'subtract';
 
     _.times(Math.abs(n), function () {
       y[method](interval);
@@ -187,7 +187,7 @@ export default function XAxisFactory(Private) {
    * @returns {*} D3 scale function
    */
   XAxis.prototype.getRange = function (domain, width) {
-    let ordered = this.ordered;
+    const ordered = this.ordered;
 
     if (ordered && ordered.date) {
       return domain.range([0, width]);
@@ -203,7 +203,7 @@ export default function XAxisFactory(Private) {
    * @returns {*} D3 x scale function
    */
   XAxis.prototype.getXScale = function (width) {
-    let domain = this.getDomain(this.getScale());
+    const domain = this.getDomain(this.getScale());
 
     return this.getRange(domain, width);
   };
@@ -235,7 +235,7 @@ export default function XAxisFactory(Private) {
    * @returns {Function} Renders the x axis to a D3 selection
    */
   XAxis.prototype.draw = function () {
-    let self = this;
+    const self = this;
     let div;
     let width;
     let height;
@@ -283,8 +283,8 @@ export default function XAxisFactory(Private) {
    * @returns {Function} Filters or rotates x axis tick labels
    */
   XAxis.prototype.filterOrRotate = function () {
-    let self = this;
-    let ordered = self.ordered;
+    const self = this;
+    const ordered = self.ordered;
     let axis;
     let labels;
 
@@ -312,13 +312,13 @@ export default function XAxisFactory(Private) {
    * @returns {Function} Rotates x axis tick labels of a D3 selection
    */
   XAxis.prototype.rotateAxisLabels = function () {
-    let self = this;
+    const self = this;
     let text;
-    let barWidth = self.xScale.rangeBand();
-    let maxRotatedLength = 120;
-    let xAxisPadding = 15;
+    const barWidth = self.xScale.rangeBand();
+    const maxRotatedLength = 120;
+    const xAxisPadding = 15;
     let svg;
-    let lengths = [];
+    const lengths = [];
     let length;
     self._attr.isRotated = false;
 
@@ -369,13 +369,13 @@ export default function XAxisFactory(Private) {
    * @returns {*|jQuery}
    */
   XAxis.prototype.truncateLabel = function (text, size) {
-    let node = d3.select(text).node();
+    const node = d3.select(text).node();
     let str = $(node).text();
-    let width = node.getBBox().width;
-    let chars = str.length;
-    let pxPerChar = width / chars;
+    const width = node.getBBox().width;
+    const chars = str.length;
+    const pxPerChar = width / chars;
     let endChar = 0;
-    let ellipsesPad = 4;
+    const ellipsesPad = 4;
 
     if (width > size) {
       endChar = Math.floor((size / pxPerChar) - ellipsesPad);
@@ -398,14 +398,14 @@ export default function XAxisFactory(Private) {
    * @returns {Function}
    */
   XAxis.prototype.filterAxisLabels = function () {
-    let self = this;
+    const self = this;
     let startX = 0;
     let maxW;
     let par;
     let myX;
     let myWidth;
     let halfWidth;
-    let padding = 1.1;
+    const padding = 1.1;
 
     return function (selection) {
       selection.selectAll('.tick text')
@@ -437,7 +437,7 @@ export default function XAxisFactory(Private) {
    * @returns {Function}
    */
   XAxis.prototype.fitTitles = function () {
-    let visEls = $('.vis-wrapper');
+    const visEls = $('.vis-wrapper');
     let xAxisChartTitle;
     let yAxisChartTitle;
     let text;
@@ -446,10 +446,10 @@ export default function XAxisFactory(Private) {
     return function () {
 
       visEls.each(function () {
-        let visEl = d3.select(this);
-        let $visEl = $(this);
-        let xAxisTitle = $visEl.find('.x-axis-title');
-        let yAxisTitle = $visEl.find('.y-axis-title');
+        const visEl = d3.select(this);
+        const $visEl = $(this);
+        const xAxisTitle = $visEl.find('.x-axis-title');
+        const yAxisTitle = $visEl.find('.y-axis-title');
         let titleWidth = xAxisTitle.width();
         let titleHeight = yAxisTitle.height();
 
@@ -505,17 +505,17 @@ export default function XAxisFactory(Private) {
    * @method updateXaxisHeight
    */
   XAxis.prototype.updateXaxisHeight = function () {
-    let selection = d3.select(this.el).selectAll('.vis-wrapper');
+    const selection = d3.select(this.el).selectAll('.vis-wrapper');
 
     selection.each(function () {
-      let visEl = d3.select(this);
+      const visEl = d3.select(this);
 
       if (visEl.select('.inner-spacer-block').node() === null) {
         visEl.select('.y-axis-spacer-block')
         .append('div')
         .attr('class', 'inner-spacer-block');
       }
-      let xAxisHt = visEl.select('.x-axis-wrapper').style('height');
+      const xAxisHt = visEl.select('.x-axis-wrapper').style('height');
 
       visEl.select('.inner-spacer-block').style('height', xAxisHt);
     });
diff --git a/src/ui/public/vislib/lib/y_axis.js b/src/ui/public/vislib/lib/y_axis.js
index 70eaa7419da3f..10c4e6dd83158 100644
--- a/src/ui/public/vislib/lib/y_axis.js
+++ b/src/ui/public/vislib/lib/y_axis.js
@@ -5,7 +5,7 @@ import errors from 'ui/errors';
 import VislibLibErrorHandlerProvider from 'ui/vislib/lib/_error_handler';
 export default function YAxisFactory(Private) {
 
-  let ErrorHandler = Private(VislibLibErrorHandlerProvider);
+  const ErrorHandler = Private(VislibLibErrorHandlerProvider);
 
   /**
    * Appends y axis to the visualization
@@ -46,7 +46,7 @@ export default function YAxisFactory(Private) {
   };
 
   YAxis.prototype._validateUserExtents = function (domain) {
-    let self = this;
+    const self = this;
 
     return domain.map(function (val) {
       val = parseInt(val, 10);
@@ -58,8 +58,8 @@ export default function YAxisFactory(Private) {
   };
 
   YAxis.prototype._getExtents = function (domain) {
-    let min = domain[0];
-    let max = domain[1];
+    const min = domain[0];
+    const max = domain[1];
 
     if (this._isUserDefined()) return this._validateUserExtents(domain);
     if (this._isYExtents()) return domain;
@@ -112,8 +112,8 @@ export default function YAxisFactory(Private) {
    * @returns {D3.Scale.QuantitiveScale|*} D3 yScale function
    */
   YAxis.prototype.getYScale = function (height) {
-    let scale = this._getScaleType(this._attr.scale);
-    let domain = this._getExtents(this.domain);
+    const scale = this._getScaleType(this._attr.scale);
+    const domain = this._getExtents(this.domain);
 
     this.yScale = scale
     .domain(domain)
@@ -130,7 +130,7 @@ export default function YAxisFactory(Private) {
   };
 
   YAxis.prototype.tickFormat = function () {
-    let isPercentage = this._attr.mode === 'percentage';
+    const isPercentage = this._attr.mode === 'percentage';
     if (isPercentage) return d3.format('%');
     if (this.yAxisFormatter) return this.yAxisFormatter;
     return d3.format('n');
@@ -148,7 +148,7 @@ export default function YAxisFactory(Private) {
    * @returns {D3.Svg.Axis|*} D3 yAxis function
    */
   YAxis.prototype.getYAxis = function (height) {
-    let yScale = this.getYScale(height);
+    const yScale = this.getYScale(height);
     this._validateYScale(yScale);
 
     // Create the d3 yAxis function
@@ -172,7 +172,7 @@ export default function YAxisFactory(Private) {
    * @returns {number} Number of y axis ticks
    */
   YAxis.prototype.tickScale = function (height) {
-    let yTickScale = d3.scale.linear()
+    const yTickScale = d3.scale.linear()
     .clamp(true)
     .domain([20, 40, 1000])
     .range([0, 3, 11]);
@@ -187,29 +187,29 @@ export default function YAxisFactory(Private) {
    * @returns {Function} Renders y axis to visualization
    */
   YAxis.prototype.draw = function () {
-    let self = this;
-    let margin = this._attr.margin;
-    let mode = this._attr.mode;
-    let isWiggleOrSilhouette = (mode === 'wiggle' || mode === 'silhouette');
+    const self = this;
+    const margin = this._attr.margin;
+    const mode = this._attr.mode;
+    const isWiggleOrSilhouette = (mode === 'wiggle' || mode === 'silhouette');
 
     return function (selection) {
       selection.each(function () {
-        let el = this;
+        const el = this;
 
-        let div = d3.select(el);
-        let width = $(el).parent().width();
-        let height = $(el).height();
-        let adjustedHeight = height - margin.top - margin.bottom;
+        const div = d3.select(el);
+        const width = $(el).parent().width();
+        const height = $(el).height();
+        const adjustedHeight = height - margin.top - margin.bottom;
 
         // Validate whether width and height are not 0 or `NaN`
         self.validateWidthandHeight(width, adjustedHeight);
 
-        let yAxis = self.getYAxis(adjustedHeight);
+        const yAxis = self.getYAxis(adjustedHeight);
 
         // The yAxis should not appear if mode is set to 'wiggle' or 'silhouette'
         if (!isWiggleOrSilhouette) {
           // Append svg and y axis
-          let svg = div.append('svg')
+          const svg = div.append('svg')
           .attr('width', width)
           .attr('height', height);
 
@@ -218,9 +218,9 @@ export default function YAxisFactory(Private) {
           .attr('transform', 'translate(' + (width - 2) + ',' + margin.top + ')')
           .call(yAxis);
 
-          let container = svg.select('g.y.axis').node();
+          const container = svg.select('g.y.axis').node();
           if (container) {
-            let cWidth = Math.max(width, container.getBBox().width);
+            const cWidth = Math.max(width, container.getBBox().width);
             svg.attr('width', cWidth);
             svg.select('g')
             .attr('transform', 'translate(' + (cWidth - 2) + ',' + margin.top + ')');
diff --git a/src/ui/public/vislib/vis.js b/src/ui/public/vislib/vis.js
index 27569fa04c60e..835f3324ea01e 100644
--- a/src/ui/public/vislib/vis.js
+++ b/src/ui/public/vislib/vis.js
@@ -10,10 +10,10 @@ import VislibVisualizationsVisTypesProvider from 'ui/vislib/visualizations/vis_t
 export default function VisFactory(Private) {
 
 
-  let ResizeChecker = Private(VislibLibResizeCheckerProvider);
-  let Events = Private(EventsProvider);
-  let handlerTypes = Private(VislibLibHandlerHandlerTypesProvider);
-  let chartTypes = Private(VislibVisualizationsVisTypesProvider);
+  const ResizeChecker = Private(VislibLibResizeCheckerProvider);
+  const Events = Private(EventsProvider);
+  const handlerTypes = Private(VislibLibHandlerHandlerTypesProvider);
+  const chartTypes = Private(VislibVisualizationsVisTypesProvider);
 
   /**
    * Creates the visualizations.
@@ -49,7 +49,7 @@ export default function VisFactory(Private) {
    * @param data {Object} Elasticsearch query results
    */
   Vis.prototype.render = function (data, uiState) {
-    let chartType = this._attr.type;
+    const chartType = this._attr.type;
 
     if (!data) {
       throw new Error('No valid data!');
@@ -154,9 +154,9 @@ export default function VisFactory(Private) {
    * @returns {*}
    */
   Vis.prototype.on = function (event, listener) {
-    let first = this.listenerCount(event) === 0;
-    let ret = Events.prototype.on.call(this, event, listener);
-    let added = this.listenerCount(event) > 0;
+    const first = this.listenerCount(event) === 0;
+    const ret = Events.prototype.on.call(this, event, listener);
+    const added = this.listenerCount(event) > 0;
 
     // if this is the first listener added for the event
     // enable the event in the handler
@@ -173,9 +173,9 @@ export default function VisFactory(Private) {
    * @returns {*}
    */
   Vis.prototype.off = function (event, listener) {
-    let last = this.listenerCount(event) === 1;
-    let ret = Events.prototype.off.call(this, event, listener);
-    let removed = this.listenerCount(event) === 0;
+    const last = this.listenerCount(event) === 1;
+    const ret = Events.prototype.off.call(this, event, listener);
+    const removed = this.listenerCount(event) === 0;
 
     // Once all listeners are removed, disable the events in the handler
     if (last && removed && this.handler) this.handler.disable(event);
diff --git a/src/ui/public/vislib/visualizations/_chart.js b/src/ui/public/vislib/visualizations/_chart.js
index 4286df6b16279..c68dfbb9c13f9 100644
--- a/src/ui/public/vislib/visualizations/_chart.js
+++ b/src/ui/public/vislib/visualizations/_chart.js
@@ -6,8 +6,8 @@ import VislibLibDispatchProvider from 'ui/vislib/lib/dispatch';
 import VislibComponentsTooltipProvider from 'ui/vislib/components/tooltip';
 export default function ChartBaseClass(Private) {
 
-  let Dispatch = Private(VislibLibDispatchProvider);
-  let Tooltip = Private(VislibComponentsTooltipProvider);
+  const Dispatch = Private(VislibLibDispatchProvider);
+  const Tooltip = Private(VislibComponentsTooltipProvider);
 
   /**
    * The Base Class for all visualizations.
@@ -28,11 +28,11 @@ export default function ChartBaseClass(Private) {
     this.chartData = chartData;
     this.tooltips = [];
 
-    let events = this.events = new Dispatch(handler);
+    const events = this.events = new Dispatch(handler);
 
     if (_.get(this.handler, '_attr.addTooltip')) {
-      let $el = this.handler.el;
-      let formatter = this.handler.data.get('tooltipFormatter');
+      const $el = this.handler.el;
+      const formatter = this.handler.data.get('tooltipFormatter');
 
       // Add tooltip
       this.tooltip = new Tooltip('chart', $el, formatter, events);
@@ -50,7 +50,7 @@ export default function ChartBaseClass(Private) {
    * @returns {HTMLElement} Contains the D3 chart
    */
   Chart.prototype.render = function () {
-    let selection = d3.select(this.chartEl);
+    const selection = d3.select(this.chartEl);
 
     selection.selectAll('*').remove();
     selection.call(this.draw());
@@ -64,7 +64,7 @@ export default function ChartBaseClass(Private) {
    */
   Chart.prototype._addIdentifier = function (selection, labelProp) {
     labelProp = labelProp || 'label';
-    let labels = this.handler.data.labels;
+    const labels = this.handler.data.labels;
 
     function resolveLabel(datum) {
       if (labels.length === 1) return labels[0];
@@ -73,7 +73,7 @@ export default function ChartBaseClass(Private) {
     }
 
     selection.each(function (datum) {
-      let label = resolveLabel(datum);
+      const label = resolveLabel(datum);
       if (label != null) dataLabel(this, label);
     });
   };
diff --git a/src/ui/public/vislib/visualizations/_map.js b/src/ui/public/vislib/visualizations/_map.js
index b61de613488cd..de550c08001dd 100644
--- a/src/ui/public/vislib/visualizations/_map.js
+++ b/src/ui/public/vislib/visualizations/_map.js
@@ -13,19 +13,19 @@ import VislibVisualizationsMarkerTypesGeohashGridProvider from 'ui/vislib/visual
 import VislibVisualizationsMarkerTypesHeatmapProvider from 'ui/vislib/visualizations/marker_types/heatmap';
 export default function MapFactory(Private, tilemap, $sanitize) {
 
-  let defaultMapZoom = 2;
-  let defaultMapCenter = [15, 5];
-  let defaultMarkerType = 'Scaled Circle Markers';
+  const defaultMapZoom = 2;
+  const defaultMapCenter = [15, 5];
+  const defaultMarkerType = 'Scaled Circle Markers';
 
-  let tilemapOptions = tilemap.options;
-  let attribution = $sanitize(marked(tilemapOptions.attribution));
+  const tilemapOptions = tilemap.options;
+  const attribution = $sanitize(marked(tilemapOptions.attribution));
 
-  let mapTiles = {
+  const mapTiles = {
     url: tilemap.url,
     options: _.assign({}, tilemapOptions, { attribution })
   };
 
-  let markerTypes = {
+  const markerTypes = {
     'Scaled Circle Markers': Private(VislibVisualizationsMarkerTypesScaledCirclesProvider),
     'Shaded Circle Markers': Private(VislibVisualizationsMarkerTypesShadedCirclesProvider),
     'Shaded Geohash Grid': Private(VislibVisualizationsMarkerTypesGeohashGridProvider),
@@ -55,7 +55,7 @@ export default function MapFactory(Private, tilemap, $sanitize) {
     this._mapCenter = params.center || defaultMapCenter;
     this._attr = params.attr || {};
 
-    let mapOptions = {
+    const mapOptions = {
       minZoom: tilemapOptions.minZoom,
       maxZoom: tilemapOptions.maxZoom,
       noWrap: true,
@@ -70,8 +70,8 @@ export default function MapFactory(Private, tilemap, $sanitize) {
   TileMapMap.prototype.addBoundingControl = function () {
     if (this._boundingControl) return;
 
-    let self = this;
-    let drawOptions = { draw: {} };
+    const self = this;
+    const drawOptions = { draw: {} };
 
     _.each(['polyline', 'polygon', 'circle', 'marker', 'rectangle'], function (drawShape) {
       if (self._events && !self._events.listenerCount(drawShape)) {
@@ -93,11 +93,11 @@ export default function MapFactory(Private, tilemap, $sanitize) {
   TileMapMap.prototype.addFitControl = function () {
     if (this._fitControl) return;
 
-    let self = this;
-    let fitContainer = L.DomUtil.create('div', 'leaflet-control leaflet-bar leaflet-control-fit');
+    const self = this;
+    const fitContainer = L.DomUtil.create('div', 'leaflet-control leaflet-bar leaflet-control-fit');
 
     // Add button to fit container to points
-    let FitControl = L.Control.extend({
+    const FitControl = L.Control.extend({
       options: {
         position: 'topleft'
       },
@@ -129,7 +129,7 @@ export default function MapFactory(Private, tilemap, $sanitize) {
   TileMapMap.prototype.addTitle = function (mapLabel) {
     if (this._label) return;
 
-    let label = this._label = L.control();
+    const label = this._label = L.control();
 
     label.onAdd = function () {
       this._div = L.DomUtil.create('div', 'tilemap-info tilemap-label');
@@ -200,13 +200,13 @@ export default function MapFactory(Private, tilemap, $sanitize) {
    * @return {Object} marker layer
    */
   TileMapMap.prototype._createMarkers = function (options) {
-    let MarkerType = markerTypes[this._markerType];
+    const MarkerType = markerTypes[this._markerType];
     return new MarkerType(this.map, this._geoJson, options);
   };
 
   TileMapMap.prototype._attachEvents = function () {
-    let self = this;
-    let saturateTiles = self.saturateTiles.bind(self);
+    const self = this;
+    const saturateTiles = self.saturateTiles.bind(self);
 
     this._tileLayer.on('tileload', saturateTiles);
 
@@ -233,11 +233,11 @@ export default function MapFactory(Private, tilemap, $sanitize) {
     });
 
     this.map.on('draw:created', function (e) {
-      let drawType = e.layerType;
+      const drawType = e.layerType;
       if (!self._events || !self._events.listenerCount(drawType)) return;
 
       // TODO: Different drawTypes need differ info. Need a switch on the object creation
-      let bounds = e.layer.getBounds();
+      const bounds = e.layer.getBounds();
 
       let SElng = bounds.getSouthEast().lng;
       if (SElng > 180) {
diff --git a/src/ui/public/vislib/visualizations/_point_series_chart.js b/src/ui/public/vislib/visualizations/_point_series_chart.js
index 31b60787db1dd..472cad10bac13 100644
--- a/src/ui/public/vislib/visualizations/_point_series_chart.js
+++ b/src/ui/public/vislib/visualizations/_point_series_chart.js
@@ -6,9 +6,9 @@ import errors from 'ui/errors';
 
 export default function PointSeriesChartProvider(Private) {
 
-  let Chart = Private(VislibVisualizationsChartProvider);
-  let Tooltip = Private(VislibComponentsTooltipProvider);
-  let touchdownTmpl = _.template(require('ui/vislib/partials/touchdown.tmpl.html'));
+  const Chart = Private(VislibVisualizationsChartProvider);
+  const Tooltip = Private(VislibComponentsTooltipProvider);
+  const touchdownTmpl = _.template(require('ui/vislib/partials/touchdown.tmpl.html'));
 
   _.class(PointSeriesChart).inherits(Chart);
   function PointSeriesChart(handler, chartEl, chartData) {
@@ -24,8 +24,8 @@ export default function PointSeriesChartProvider(Private) {
     let currentStackIndex = 0;
 
     return function (d, y0, y) {
-      let firstStack = currentStackIndex % stackCount === 0;
-      let lastStack = ++currentStackIndex === stackCount;
+      const firstStack = currentStackIndex % stackCount === 0;
+      const lastStack = ++currentStackIndex === stackCount;
 
       if (firstStack) {
         currentStackOffsets = [0, 0];
@@ -51,14 +51,14 @@ export default function PointSeriesChartProvider(Private) {
    * @returns {Array} Stacked data objects with x, y, and y0 values
    */
   PointSeriesChart.prototype.stackData = function (data) {
-    let self = this;
-    let isHistogram = (this._attr.type === 'histogram' && this._attr.mode === 'stacked');
-    let stack = this._attr.stack;
+    const self = this;
+    const isHistogram = (this._attr.type === 'histogram' && this._attr.mode === 'stacked');
+    const stack = this._attr.stack;
 
     if (isHistogram) stack.out(self._stackMixedValues(data.series.length));
 
     return stack(data.series.map(function (d) {
-      let label = d.label;
+      const label = d.label;
       return d.values.map(function (e, i) {
         return {
           _input: e,
@@ -92,37 +92,37 @@ export default function PointSeriesChartProvider(Private) {
    * @returns {D3.Selection}
    */
   PointSeriesChart.prototype.createEndZones = function (svg) {
-    let self = this;
-    let xAxis = this.handler.xAxis;
-    let xScale = xAxis.xScale;
-    let ordered = xAxis.ordered;
-    let missingMinMax = !ordered || _.isUndefined(ordered.min) || _.isUndefined(ordered.max);
+    const self = this;
+    const xAxis = this.handler.xAxis;
+    const xScale = xAxis.xScale;
+    const ordered = xAxis.ordered;
+    const missingMinMax = !ordered || _.isUndefined(ordered.min) || _.isUndefined(ordered.max);
 
     if (missingMinMax || ordered.endzones === false) return;
 
-    let attr = this.handler._attr;
-    let height = attr.height;
-    let width = attr.width;
-    let margin = attr.margin;
-    let color = '#004c99';
+    const attr = this.handler._attr;
+    const height = attr.height;
+    const width = attr.width;
+    const margin = attr.margin;
+    const color = '#004c99';
 
     // we don't want to draw endzones over our min and max values, they
     // are still a part of the dataset. We want to start the endzones just
     // outside of them so we will use these values rather than ordered.min/max
-    let oneUnit = (ordered.units || _.identity)(1);
-    let beyondMin = ordered.min - oneUnit;
-    let beyondMax = ordered.max + oneUnit;
+    const oneUnit = (ordered.units || _.identity)(1);
+    const beyondMin = ordered.min - oneUnit;
+    const beyondMax = ordered.max + oneUnit;
 
     // points on this axis represent the amount of time they cover,
     // so draw the endzones at the actual time bounds
-    let leftEndzone = {
+    const leftEndzone = {
       x: 0,
       w: Math.max(xScale(ordered.min), 0)
     };
 
-    let rightLastVal = xAxis.expandLastBucket ? ordered.max : Math.min(ordered.max, _.last(xAxis.xValues));
-    let rightStart = rightLastVal + oneUnit;
-    let rightEndzone = {
+    const rightLastVal = xAxis.expandLastBucket ? ordered.max : Math.min(ordered.max, _.last(xAxis.xValues));
+    const rightStart = rightLastVal + oneUnit;
+    const rightEndzone = {
       x: xScale(rightStart),
       w: Math.max(width - xScale(rightStart), 0)
     };
@@ -144,13 +144,13 @@ export default function PointSeriesChartProvider(Private) {
     });
 
     function callPlay(event) {
-      let boundData = event.target.__data__;
-      let mouseChartXCoord = event.clientX - self.chartEl.getBoundingClientRect().left;
-      let wholeBucket = boundData && boundData.x != null;
+      const boundData = event.target.__data__;
+      const mouseChartXCoord = event.clientX - self.chartEl.getBoundingClientRect().left;
+      const wholeBucket = boundData && boundData.x != null;
 
       // the min and max that the endzones start in
-      let min = leftEndzone.w;
-      let max = rightEndzone.x;
+      const min = leftEndzone.w;
+      const max = rightEndzone.x;
 
       // bounds of the cursor to consider
       let xLeft = mouseChartXCoord;
@@ -171,7 +171,7 @@ export default function PointSeriesChartProvider(Private) {
       return touchdownTmpl(callPlay(d3.event));
     }
 
-    let endzoneTT = new Tooltip('endzones', this.handler.el, textFormatter, null);
+    const endzoneTT = new Tooltip('endzones', this.handler.el, textFormatter, null);
     this.tooltips.push(endzoneTT);
     endzoneTT.order = 0;
     endzoneTT.showCondition = function inEndzone() {
diff --git a/src/ui/public/vislib/visualizations/area_chart.js b/src/ui/public/vislib/visualizations/area_chart.js
index 4b0d1d1f48835..8eea2c38ba731 100644
--- a/src/ui/public/vislib/visualizations/area_chart.js
+++ b/src/ui/public/vislib/visualizations/area_chart.js
@@ -6,8 +6,8 @@ import VislibVisualizationsPointSeriesChartProvider from 'ui/vislib/visualizatio
 import VislibVisualizationsTimeMarkerProvider from 'ui/vislib/visualizations/time_marker';
 export default function AreaChartFactory(Private) {
 
-  let PointSeriesChart = Private(VislibVisualizationsPointSeriesChartProvider);
-  let TimeMarker = Private(VislibVisualizationsTimeMarkerProvider);
+  const PointSeriesChart = Private(VislibVisualizationsPointSeriesChartProvider);
+  const TimeMarker = Private(VislibVisualizationsTimeMarkerProvider);
 
   /**
    * Area chart visualization
@@ -33,14 +33,14 @@ export default function AreaChartFactory(Private) {
     if (this.isOverlapping) {
 
       // Default opacity should return to 0.6 on mouseout
-      let defaultOpacity = 0.6;
+      const defaultOpacity = 0.6;
       handler._attr.defaultOpacity = defaultOpacity;
       handler.highlight = function (element) {
-        let label = this.getAttribute('data-label');
+        const label = this.getAttribute('data-label');
         if (!label) return;
 
-        let highlightOpacity = 0.8;
-        let highlightElements = $('[data-label]', element.parentNode).filter(
+        const highlightOpacity = 0.8;
+        const highlightElements = $('[data-label]', element.parentNode).filter(
           function (els, el) {
             return `${$(el).data('label')}` === label;
           });
@@ -72,15 +72,15 @@ export default function AreaChartFactory(Private) {
    * @returns {D3.UpdateSelection} SVG with path added
    */
   AreaChart.prototype.addPath = function (svg, layers) {
-    let self = this;
-    let ordered = this.handler.data.get('ordered');
-    let isTimeSeries = (ordered && ordered.date);
-    let isOverlapping = this.isOverlapping;
-    let color = this.handler.data.getColorFunc();
-    let xScale = this.handler.xAxis.xScale;
-    let yScale = this.handler.yAxis.yScale;
-    let interpolate = (this._attr.smoothLines) ? 'cardinal' : this._attr.interpolate;
-    let area = d3.svg.area()
+    const self = this;
+    const ordered = this.handler.data.get('ordered');
+    const isTimeSeries = (ordered && ordered.date);
+    const isOverlapping = this.isOverlapping;
+    const color = this.handler.data.getColorFunc();
+    const xScale = this.handler.xAxis.xScale;
+    const yScale = this.handler.yAxis.yScale;
+    const interpolate = (this._attr.smoothLines) ? 'cardinal' : this._attr.interpolate;
+    const area = d3.svg.area()
     .x(function (d) {
       if (isTimeSeries) {
         return xScale(d.x);
@@ -105,7 +105,7 @@ export default function AreaChartFactory(Private) {
     .interpolate(interpolate);
 
     // Data layers
-    let layer = svg.selectAll('.layer')
+    const layer = svg.selectAll('.layer')
     .data(layers)
     .enter()
     .append('g')
@@ -114,7 +114,7 @@ export default function AreaChartFactory(Private) {
     });
 
     // Append path
-    let path = layer.append('path')
+    const path = layer.append('path')
     .call(this._addIdentifier)
     .style('fill', function (d) {
       return color(d[0].label);
@@ -139,13 +139,13 @@ export default function AreaChartFactory(Private) {
    * @returns {D3.Selection} circles with event listeners attached
    */
   AreaChart.prototype.addCircleEvents = function (element, svg) {
-    let events = this.events;
-    let isBrushable = events.isBrushable();
-    let brush = isBrushable ? events.addBrushEvent(svg) : undefined;
-    let hover = events.addHoverEvent();
-    let mouseout = events.addMouseoutEvent();
-    let click = events.addClickEvent();
-    let attachedEvents = element.call(hover).call(mouseout).call(click);
+    const events = this.events;
+    const isBrushable = events.isBrushable();
+    const brush = isBrushable ? events.addBrushEvent(svg) : undefined;
+    const hover = events.addHoverEvent();
+    const mouseout = events.addMouseoutEvent();
+    const click = events.addClickEvent();
+    const attachedEvents = element.call(hover).call(mouseout).call(click);
 
     if (isBrushable) {
       attachedEvents.call(brush);
@@ -163,27 +163,25 @@ export default function AreaChartFactory(Private) {
    * @returns {D3.UpdateSelection} SVG with circles added
    */
   AreaChart.prototype.addCircles = function (svg, data) {
-    let self = this;
-    let color = this.handler.data.getColorFunc();
-    let xScale = this.handler.xAxis.xScale;
-    let yScale = this.handler.yAxis.yScale;
-    let ordered = this.handler.data.get('ordered');
-    let circleRadius = 12;
-    let circleStrokeWidth = 0;
-    let tooltip = this.tooltip;
-    let isTooltip = this._attr.addTooltip;
-    let isOverlapping = this.isOverlapping;
-    let layer;
-    let circles;
-
-    layer = svg.selectAll('.points')
+    const self = this;
+    const color = this.handler.data.getColorFunc();
+    const xScale = this.handler.xAxis.xScale;
+    const yScale = this.handler.yAxis.yScale;
+    const ordered = this.handler.data.get('ordered');
+    const circleRadius = 12;
+    const circleStrokeWidth = 0;
+    const tooltip = this.tooltip;
+    const isTooltip = this._attr.addTooltip;
+    const isOverlapping = this.isOverlapping;
+
+    const layer = svg.selectAll('.points')
     .data(data)
     .enter()
       .append('g')
       .attr('class', 'points area');
 
     // append the circles
-    circles = layer
+    const circles = layer
     .selectAll('circles')
     .data(function appendData(data) {
       return data.filter(function isZeroOrNull(d) {
@@ -240,9 +238,9 @@ export default function AreaChartFactory(Private) {
    */
   AreaChart.prototype.addClipPath = function (svg, width, height) {
     // Prevents circles from being clipped at the top of the chart
-    let startX = 0;
-    let startY = 0;
-    let id = 'chart-area' + _.uniqueId();
+    const startX = 0;
+    const startY = 0;
+    const id = 'chart-area' + _.uniqueId();
 
     // Creating clipPath
     return svg
@@ -257,11 +255,11 @@ export default function AreaChartFactory(Private) {
   };
 
   AreaChart.prototype.checkIfEnoughData = function () {
-    let series = this.chartData.series;
-    let message = 'Area charts require more than one data point. Try adding ' +
+    const series = this.chartData.series;
+    const message = 'Area charts require more than one data point. Try adding ' +
       'an X-Axis Aggregation';
 
-    let notEnoughData = series.some(function (obj) {
+    const notEnoughData = series.some(function (obj) {
       return obj.values.length < 2;
     });
 
@@ -271,8 +269,8 @@ export default function AreaChartFactory(Private) {
   };
 
   AreaChart.prototype.validateWiggleSelection = function () {
-    let isWiggle = this._attr.mode === 'wiggle';
-    let ordered = this.handler.data.get('ordered');
+    const isWiggle = this._attr.mode === 'wiggle';
+    const ordered = this.handler.data.get('ordered');
 
     if (isWiggle && !ordered) throw new errors.InvalidWiggleSelection();
   };
@@ -285,18 +283,18 @@ export default function AreaChartFactory(Private) {
    */
   AreaChart.prototype.draw = function () {
     // Attributes
-    let self = this;
-    let xScale = this.handler.xAxis.xScale;
-    let $elem = $(this.chartEl);
-    let margin = this._attr.margin;
-    let elWidth = this._attr.width = $elem.width();
-    let elHeight = this._attr.height = $elem.height();
-    let yMin = this.handler.yAxis.yMin;
-    let yScale = this.handler.yAxis.yScale;
-    let minWidth = 20;
-    let minHeight = 20;
-    let addTimeMarker = this._attr.addTimeMarker;
-    let times = this._attr.times || [];
+    const self = this;
+    const xScale = this.handler.xAxis.xScale;
+    const $elem = $(this.chartEl);
+    const margin = this._attr.margin;
+    const elWidth = this._attr.width = $elem.width();
+    const elHeight = this._attr.height = $elem.height();
+    const yMin = this.handler.yAxis.yMin;
+    const yScale = this.handler.yAxis.yScale;
+    const minWidth = 20;
+    const minHeight = 20;
+    const addTimeMarker = this._attr.addTimeMarker;
+    const times = this._attr.times || [];
     let timeMarker;
     let div;
     let svg;
@@ -361,7 +359,7 @@ export default function AreaChartFactory(Private) {
         self.addCircleEvents(circles, svg);
 
         // chart base line
-        let line = svg.append('line')
+        const line = svg.append('line')
         .attr('class', 'base-line')
         .attr('x1', 0)
         .attr('y1', yScale(0))
diff --git a/src/ui/public/vislib/visualizations/column_chart.js b/src/ui/public/vislib/visualizations/column_chart.js
index b4c8b220d37c2..722a2461e77c3 100644
--- a/src/ui/public/vislib/visualizations/column_chart.js
+++ b/src/ui/public/vislib/visualizations/column_chart.js
@@ -7,8 +7,8 @@ import VislibVisualizationsPointSeriesChartProvider from 'ui/vislib/visualizatio
 import VislibVisualizationsTimeMarkerProvider from 'ui/vislib/visualizations/time_marker';
 export default function ColumnChartFactory(Private) {
 
-  let PointSeriesChart = Private(VislibVisualizationsPointSeriesChartProvider);
-  let TimeMarker = Private(VislibVisualizationsTimeMarkerProvider);
+  const PointSeriesChart = Private(VislibVisualizationsPointSeriesChartProvider);
+  const TimeMarker = Private(VislibVisualizationsTimeMarkerProvider);
 
   /**
    * Vertical Bar Chart Visualization: renders vertical and/or stacked bars
@@ -44,21 +44,19 @@ export default function ColumnChartFactory(Private) {
    * @returns {D3.UpdateSelection} SVG with rect added
    */
   ColumnChart.prototype.addBars = function (svg, layers) {
-    let self = this;
-    let color = this.handler.data.getColorFunc();
-    let tooltip = this.tooltip;
-    let isTooltip = this._attr.addTooltip;
-    let layer;
-    let bars;
+    const self = this;
+    const color = this.handler.data.getColorFunc();
+    const tooltip = this.tooltip;
+    const isTooltip = this._attr.addTooltip;
 
-    layer = svg.selectAll('.layer')
+    const layer = svg.selectAll('.layer')
     .data(layers)
     .enter().append('g')
     .attr('class', function (d, i) {
       return 'series ' + i;
     });
 
-    bars = layer.selectAll('rect')
+    const bars = layer.selectAll('rect')
     .data(function (d) {
       return d;
     });
@@ -94,7 +92,7 @@ export default function ColumnChartFactory(Private) {
    * @returns {D3.UpdateSelection}
    */
   ColumnChart.prototype.updateBars = function (bars) {
-    let offset = this._attr.mode;
+    const offset = this._attr.mode;
 
     if (offset === 'grouped') {
       return this.addGroupedBars(bars);
@@ -110,16 +108,16 @@ export default function ColumnChartFactory(Private) {
    * @returns {D3.UpdateSelection}
    */
   ColumnChart.prototype.addStackedBars = function (bars) {
-    let data = this.chartData;
-    let xScale = this.handler.xAxis.xScale;
-    let yScale = this.handler.yAxis.yScale;
-    let height = yScale.range()[0];
-    let yMin = this.handler.yAxis.yScale.domain()[0];
+    const data = this.chartData;
+    const xScale = this.handler.xAxis.xScale;
+    const yScale = this.handler.yAxis.yScale;
+    const height = yScale.range()[0];
+    const yMin = this.handler.yAxis.yScale.domain()[0];
 
     let barWidth;
     if (data.ordered && data.ordered.date) {
-      let start = data.ordered.min;
-      let end = moment(data.ordered.min).add(data.ordered.interval).valueOf();
+      const start = data.ordered.min;
+      const end = moment(data.ordered.min).add(data.ordered.interval).valueOf();
 
       barWidth = xScale(end) - xScale(start);
       barWidth = barWidth - Math.min(barWidth * 0.25, 15);
@@ -172,23 +170,23 @@ export default function ColumnChartFactory(Private) {
    * @returns {D3.UpdateSelection}
    */
   ColumnChart.prototype.addGroupedBars = function (bars) {
-    let xScale = this.handler.xAxis.xScale;
-    let yScale = this.handler.yAxis.yScale;
-    let data = this.chartData;
-    let n = data.series.length;
-    let height = yScale.range()[0];
-    let groupSpacingPercentage = 0.15;
-    let isTimeScale = (data.ordered && data.ordered.date);
-    let minWidth = 1;
+    const xScale = this.handler.xAxis.xScale;
+    const yScale = this.handler.yAxis.yScale;
+    const data = this.chartData;
+    const n = data.series.length;
+    const height = yScale.range()[0];
+    const groupSpacingPercentage = 0.15;
+    const isTimeScale = (data.ordered && data.ordered.date);
+    const minWidth = 1;
     let barWidth;
 
     // update
     bars
     .attr('x', function (d, i, j) {
       if (isTimeScale) {
-        let groupWidth = xScale(data.ordered.min + data.ordered.interval) -
+        const groupWidth = xScale(data.ordered.min + data.ordered.interval) -
           xScale(data.ordered.min);
-        let groupSpacing = groupWidth * groupSpacingPercentage;
+        const groupSpacing = groupWidth * groupSpacingPercentage;
 
         barWidth = (groupWidth - groupSpacing) / n;
 
@@ -231,13 +229,13 @@ export default function ColumnChartFactory(Private) {
    * @returns {D3.Selection} rect with event listeners attached
    */
   ColumnChart.prototype.addBarEvents = function (element, svg) {
-    let events = this.events;
-    let isBrushable = events.isBrushable();
-    let brush = isBrushable ? events.addBrushEvent(svg) : undefined;
-    let hover = events.addHoverEvent();
-    let mouseout = events.addMouseoutEvent();
-    let click = events.addClickEvent();
-    let attachedEvents = element.call(hover).call(mouseout).call(click);
+    const events = this.events;
+    const isBrushable = events.isBrushable();
+    const brush = isBrushable ? events.addBrushEvent(svg) : undefined;
+    const hover = events.addHoverEvent();
+    const mouseout = events.addMouseoutEvent();
+    const click = events.addClickEvent();
+    const attachedEvents = element.call(hover).call(mouseout).call(click);
 
     if (isBrushable) {
       attachedEvents.call(brush);
@@ -253,17 +251,17 @@ export default function ColumnChartFactory(Private) {
    * @returns {Function} Creates the vertical bar chart
    */
   ColumnChart.prototype.draw = function () {
-    let self = this;
-    let $elem = $(this.chartEl);
-    let margin = this._attr.margin;
-    let elWidth = this._attr.width = $elem.width();
-    let elHeight = this._attr.height = $elem.height();
-    let yScale = this.handler.yAxis.yScale;
-    let xScale = this.handler.xAxis.xScale;
-    let minWidth = 20;
-    let minHeight = 20;
-    let addTimeMarker = this._attr.addTimeMarker;
-    let times = this._attr.times || [];
+    const self = this;
+    const $elem = $(this.chartEl);
+    const margin = this._attr.margin;
+    const elWidth = this._attr.width = $elem.width();
+    const elHeight = this._attr.height = $elem.height();
+    const yScale = this.handler.yAxis.yScale;
+    const xScale = this.handler.xAxis.xScale;
+    const minWidth = 20;
+    const minHeight = 20;
+    const addTimeMarker = this._attr.addTimeMarker;
+    const times = this._attr.times || [];
     let timeMarker;
     let div;
     let svg;
@@ -310,7 +308,7 @@ export default function ColumnChartFactory(Private) {
         // Adds event listeners
         self.addBarEvents(bars, svg);
 
-        let line = svg.append('line')
+        const line = svg.append('line')
         .attr('class', 'base-line')
         .attr('x1', 0)
         .attr('y1', yScale(0))
diff --git a/src/ui/public/vislib/visualizations/line_chart.js b/src/ui/public/vislib/visualizations/line_chart.js
index 66b1c035a460b..ae6211644fc8c 100644
--- a/src/ui/public/vislib/visualizations/line_chart.js
+++ b/src/ui/public/vislib/visualizations/line_chart.js
@@ -6,8 +6,8 @@ import VislibVisualizationsPointSeriesChartProvider from 'ui/vislib/visualizatio
 import VislibVisualizationsTimeMarkerProvider from 'ui/vislib/visualizations/time_marker';
 export default function LineChartFactory(Private) {
 
-  let PointSeriesChart = Private(VislibVisualizationsPointSeriesChartProvider);
-  let TimeMarker = Private(VislibVisualizationsTimeMarkerProvider);
+  const PointSeriesChart = Private(VislibVisualizationsPointSeriesChartProvider);
+  const TimeMarker = Private(VislibVisualizationsTimeMarkerProvider);
 
   /**
    * Line Chart Visualization
@@ -43,13 +43,13 @@ export default function LineChartFactory(Private) {
    * @returns {D3.Selection} SVG circles with event listeners attached
    */
   LineChart.prototype.addCircleEvents = function (element, svg) {
-    let events = this.events;
-    let isBrushable = events.isBrushable();
-    let brush = isBrushable ? events.addBrushEvent(svg) : undefined;
-    let hover = events.addHoverEvent();
-    let mouseout = events.addMouseoutEvent();
-    let click = events.addClickEvent();
-    let attachedEvents = element.call(hover).call(mouseout).call(click);
+    const events = this.events;
+    const isBrushable = events.isBrushable();
+    const brush = isBrushable ? events.addBrushEvent(svg) : undefined;
+    const hover = events.addHoverEvent();
+    const mouseout = events.addMouseoutEvent();
+    const click = events.addClickEvent();
+    const attachedEvents = element.call(hover).call(mouseout).call(click);
 
     if (isBrushable) {
       attachedEvents.call(brush);
@@ -67,16 +67,16 @@ export default function LineChartFactory(Private) {
    * @returns {D3.UpdateSelection} SVG with circles added
    */
   LineChart.prototype.addCircles = function (svg, data) {
-    let self = this;
-    let showCircles = this._attr.showCircles;
-    let color = this.handler.data.getColorFunc();
-    let xScale = this.handler.xAxis.xScale;
-    let yScale = this.handler.yAxis.yScale;
-    let ordered = this.handler.data.get('ordered');
-    let tooltip = this.tooltip;
-    let isTooltip = this._attr.addTooltip;
-
-    let radii = _(data)
+    const self = this;
+    const showCircles = this._attr.showCircles;
+    const color = this.handler.data.getColorFunc();
+    const xScale = this.handler.xAxis.xScale;
+    const yScale = this.handler.yAxis.yScale;
+    const ordered = this.handler.data.get('ordered');
+    const tooltip = this.tooltip;
+    const isTooltip = this._attr.addTooltip;
+
+    const radii = _(data)
     .map(function (series) {
       return _.pluck(series, '_input.z');
     })
@@ -90,15 +90,15 @@ export default function LineChartFactory(Private) {
       max: -Infinity
     });
 
-    let radiusStep = ((radii.max - radii.min) || (radii.max * 100)) / Math.pow(this._attr.radiusRatio, 2);
+    const radiusStep = ((radii.max - radii.min) || (radii.max * 100)) / Math.pow(this._attr.radiusRatio, 2);
 
-    let layer = svg.selectAll('.points')
+    const layer = svg.selectAll('.points')
     .data(data)
     .enter()
       .append('g')
       .attr('class', 'points line');
 
-    let circles = layer
+    const circles = layer
     .selectAll('circle')
     .data(function appendData(data) {
       return data.filter(function (d) {
@@ -126,9 +126,9 @@ export default function LineChartFactory(Private) {
     }
 
     function colorCircle(d) {
-      let parent = d3.select(this).node().parentNode;
-      let lengthOfParent = d3.select(parent).data()[0].length;
-      let isVisible = (lengthOfParent === 1);
+      const parent = d3.select(this).node().parentNode;
+      const lengthOfParent = d3.select(parent).data()[0].length;
+      const isVisible = (lengthOfParent === 1);
 
       // If only 1 point exists, show circle
       if (!showCircles && !isVisible) return 'none';
@@ -136,10 +136,10 @@ export default function LineChartFactory(Private) {
     }
     function getCircleRadiusFn(modifier) {
       return function getCircleRadius(d) {
-        let margin = self._attr.margin;
-        let width = self._attr.width - margin.left - margin.right;
-        let height = self._attr.height - margin.top - margin.bottom;
-        let circleRadius = (d._input.z - radii.min) / radiusStep;
+        const margin = self._attr.margin;
+        const width = self._attr.width - margin.left - margin.right;
+        const height = self._attr.height - margin.top - margin.bottom;
+        const circleRadius = (d._input.z - radii.min) / radiusStep;
 
         return _.min([Math.sqrt((circleRadius || 2) + 2), width, height]) + (modifier || 0);
       };
@@ -185,14 +185,14 @@ export default function LineChartFactory(Private) {
    * @returns {D3.UpdateSelection} SVG with paths added
    */
   LineChart.prototype.addLines = function (svg, data) {
-    let self = this;
-    let xScale = this.handler.xAxis.xScale;
-    let yScale = this.handler.yAxis.yScale;
-    let xAxisFormatter = this.handler.data.get('xAxisFormatter');
-    let color = this.handler.data.getColorFunc();
-    let ordered = this.handler.data.get('ordered');
-    let interpolate = (this._attr.smoothLines) ? 'cardinal' : this._attr.interpolate;
-    let line = d3.svg.line()
+    const self = this;
+    const xScale = this.handler.xAxis.xScale;
+    const yScale = this.handler.yAxis.yScale;
+    const xAxisFormatter = this.handler.data.get('xAxisFormatter');
+    const color = this.handler.data.getColorFunc();
+    const ordered = this.handler.data.get('ordered');
+    const interpolate = (this._attr.smoothLines) ? 'cardinal' : this._attr.interpolate;
+    const line = d3.svg.line()
     .defined(function (d) { return !_.isNull(d.y); })
     .interpolate(interpolate)
     .x(function x(d) {
@@ -204,9 +204,8 @@ export default function LineChartFactory(Private) {
     .y(function y(d) {
       return yScale(d.y);
     });
-    let lines;
 
-    lines = svg
+    const lines = svg
     .selectAll('.lines')
     .data(data)
     .enter()
@@ -237,10 +236,10 @@ export default function LineChartFactory(Private) {
    * @returns {D3.UpdateSelection} SVG with clipPath added
    */
   LineChart.prototype.addClipPath = function (svg, width, height) {
-    let clipPathBuffer = 5;
-    let startX = 0;
-    let startY = 0 - clipPathBuffer;
-    let id = 'chart-area' + _.uniqueId();
+    const clipPathBuffer = 5;
+    const startX = 0;
+    const startY = 0 - clipPathBuffer;
+    const id = 'chart-area' + _.uniqueId();
 
     return svg
     .attr('clip-path', 'url(#' + id + ')')
@@ -262,21 +261,21 @@ export default function LineChartFactory(Private) {
    * @returns {Function} Creates the line chart
    */
   LineChart.prototype.draw = function () {
-    let self = this;
-    let $elem = $(this.chartEl);
-    let margin = this._attr.margin;
-    let elWidth = this._attr.width = $elem.width();
-    let elHeight = this._attr.height = $elem.height();
-    let scaleType = this.handler.yAxis.getScaleType();
-    let yMin = this.handler.yAxis.yMin;
-    let yScale = this.handler.yAxis.yScale;
-    let xScale = this.handler.xAxis.xScale;
-    let minWidth = 20;
-    let minHeight = 20;
-    let startLineX = 0;
-    let lineStrokeWidth = 1;
-    let addTimeMarker = this._attr.addTimeMarker;
-    let times = this._attr.times || [];
+    const self = this;
+    const $elem = $(this.chartEl);
+    const margin = this._attr.margin;
+    const elWidth = this._attr.width = $elem.width();
+    const elHeight = this._attr.height = $elem.height();
+    const scaleType = this.handler.yAxis.getScaleType();
+    const yMin = this.handler.yAxis.yMin;
+    const yScale = this.handler.yAxis.yScale;
+    const xScale = this.handler.xAxis.xScale;
+    const minWidth = 20;
+    const minHeight = 20;
+    const startLineX = 0;
+    const lineStrokeWidth = 1;
+    const addTimeMarker = this._attr.addTimeMarker;
+    const times = this._attr.times || [];
     let timeMarker;
     let div;
     let svg;
@@ -287,10 +286,10 @@ export default function LineChartFactory(Private) {
 
     return function (selection) {
       selection.each(function (data) {
-        let el = this;
+        const el = this;
 
-        let layers = data.series.map(function mapSeries(d) {
-          let label = d.label;
+        const layers = data.series.map(function mapSeries(d) {
+          const label = d.label;
           return d.values.map(function mapValues(e, i) {
             return {
               _input: e,
@@ -330,7 +329,7 @@ export default function LineChartFactory(Private) {
         self.addCircleEvents(circles, svg);
         self.createEndZones(svg);
 
-        let scale = (scaleType === 'log') ? yScale(1) : yScale(0);
+        const scale = (scaleType === 'log') ? yScale(1) : yScale(0);
         if (scale) {
           svg.append('line')
           .attr('class', 'base-line')
diff --git a/src/ui/public/vislib/visualizations/marker_types/base_marker.js b/src/ui/public/vislib/visualizations/marker_types/base_marker.js
index 9164e2eb94d00..3cbcf4ed7e716 100644
--- a/src/ui/public/vislib/visualizations/marker_types/base_marker.js
+++ b/src/ui/public/vislib/visualizations/marker_types/base_marker.js
@@ -35,7 +35,7 @@ export default function MarkerFactory() {
     // ensure we only ever create 1 legend
     if (this._legend) return;
 
-    let self = this;
+    const self = this;
 
     // create the legend control, keep a reference
     self._legend = L.control({position: 'bottomright'});
@@ -43,17 +43,17 @@ export default function MarkerFactory() {
     self._legend.onAdd = function () {
       // creates all the neccessary DOM elements for the control, adds listeners
       // on relevant map events, and returns the element containing the control
-      let $div = $('<div>').addClass('tilemap-legend');
+      const $div = $('<div>').addClass('tilemap-legend');
 
       _.each(self._legendColors, function (color, i) {
-        let labelText = self._legendQuantizer
+        const labelText = self._legendQuantizer
         .invertExtent(color)
         .map(self._valueFormatter)
         .join(' – ');
 
-        let label = $('<div>').text(labelText);
+        const label = $('<div>').text(labelText);
 
-        let icon = $('<i>').css({
+        const icon = $('<i>').css({
           background: color,
           'border-color': self.darkerColor(color)
         });
@@ -76,7 +76,7 @@ export default function MarkerFactory() {
    * @return {Object}
    */
   BaseMarker.prototype.applyShadingStyle = function (value) {
-    let color = this._legendQuantizer(value);
+    const color = this._legendQuantizer(value);
 
     return {
       fillColor: color,
@@ -96,11 +96,11 @@ export default function MarkerFactory() {
    * return {undefined}
    */
   BaseMarker.prototype.bindPopup = function (feature, layer) {
-    let self = this;
+    const self = this;
 
-    let popup = layer.on({
+    const popup = layer.on({
       mouseover: function (e) {
-        let layer = e.target;
+        const layer = e.target;
         // bring layer to front if not older browser
         if (!L.Browser.ie && !L.Browser.opera) {
           layer.bringToFront();
@@ -130,7 +130,7 @@ export default function MarkerFactory() {
   };
 
   BaseMarker.prototype.destroy = function () {
-    let self = this;
+    const self = this;
 
     // remove popups
     self.popups = self.popups.filter(function (popup) {
@@ -160,13 +160,13 @@ export default function MarkerFactory() {
    * @param options {Object} Options to pass to L.geoJson
    */
   BaseMarker.prototype._createMarkerGroup = function (options) {
-    let self = this;
-    let defaultOptions = {
+    const self = this;
+    const defaultOptions = {
       onEachFeature: function (feature, layer) {
         self.bindPopup(feature, layer);
       },
       style: function (feature) {
-        let value = _.get(feature, 'properties.value');
+        const value = _.get(feature, 'properties.value');
         return self.applyShadingStyle(value);
       },
       filter: self._filterToMapBounds()
@@ -184,10 +184,10 @@ export default function MarkerFactory() {
    * @return {boolean}
    */
   BaseMarker.prototype._filterToMapBounds = function () {
-    let self = this;
+    const self = this;
     return function (feature) {
-      let mapBounds = self.map.getBounds();
-      let bucketRectBounds = _.get(feature, 'properties.rectangle');
+      const mapBounds = self.map.getBounds();
+      const bucketRectBounds = _.get(feature, 'properties.rectangle');
       return mapBounds.intersects(bucketRectBounds);
     };
   };
@@ -203,11 +203,11 @@ export default function MarkerFactory() {
    */
   BaseMarker.prototype._showTooltip = function (feature, latLng) {
     if (!this.map) return;
-    let lat = _.get(feature, 'geometry.coordinates.1');
-    let lng = _.get(feature, 'geometry.coordinates.0');
+    const lat = _.get(feature, 'geometry.coordinates.1');
+    const lng = _.get(feature, 'geometry.coordinates.0');
     latLng = latLng || L.latLng(lat, lng);
 
-    let content = this._tooltipFormatter(feature);
+    const content = this._tooltipFormatter(feature);
 
     if (!content) return;
     this._createTooltip(content, latLng);
@@ -239,15 +239,15 @@ export default function MarkerFactory() {
    * return {undefined}
    */
   BaseMarker.prototype.quantizeLegendColors = function () {
-    let min = _.get(this.geoJson, 'properties.allmin', 0);
-    let max = _.get(this.geoJson, 'properties.allmax', 1);
-    let quantizeDomain = (min !== max) ? [min, max] : d3.scale.quantize().domain();
-
-    let reds1 = ['#ff6128'];
-    let reds3 = ['#fecc5c', '#fd8d3c', '#e31a1c'];
-    let reds5 = ['#fed976', '#feb24c', '#fd8d3c', '#f03b20', '#bd0026'];
-    let bottomCutoff = 2;
-    let middleCutoff = 24;
+    const min = _.get(this.geoJson, 'properties.allmin', 0);
+    const max = _.get(this.geoJson, 'properties.allmax', 1);
+    const quantizeDomain = (min !== max) ? [min, max] : d3.scale.quantize().domain();
+
+    const reds1 = ['#ff6128'];
+    const reds3 = ['#fecc5c', '#fd8d3c', '#e31a1c'];
+    const reds5 = ['#fed976', '#feb24c', '#fd8d3c', '#f03b20', '#bd0026'];
+    const bottomCutoff = 2;
+    const middleCutoff = 24;
 
     if (max - min <= bottomCutoff) {
       this._legendColors = reds1;
diff --git a/src/ui/public/vislib/visualizations/marker_types/geohash_grid.js b/src/ui/public/vislib/visualizations/marker_types/geohash_grid.js
index 2dd57ec9fc035..d09575cce4bee 100644
--- a/src/ui/public/vislib/visualizations/marker_types/geohash_grid.js
+++ b/src/ui/public/vislib/visualizations/marker_types/geohash_grid.js
@@ -3,7 +3,7 @@ import L from 'leaflet';
 import VislibVisualizationsMarkerTypesBaseMarkerProvider from 'ui/vislib/visualizations/marker_types/base_marker';
 export default function GeohashGridMarkerFactory(Private) {
 
-  let BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
+  const BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
 
   /**
    * Map overlay: rectangles that show the geohash grid bounds
@@ -14,19 +14,19 @@ export default function GeohashGridMarkerFactory(Private) {
    */
   _.class(GeohashGridMarker).inherits(BaseMarker);
   function GeohashGridMarker(map, geoJson, params) {
-    let self = this;
+    const self = this;
     GeohashGridMarker.Super.apply(this, arguments);
 
     // super min and max from all chart data
-    let min = this.geoJson.properties.allmin;
-    let max = this.geoJson.properties.allmax;
+    const min = this.geoJson.properties.allmin;
+    const max = this.geoJson.properties.allmax;
 
     this._createMarkerGroup({
       pointToLayer: function (feature, latlng) {
-        let geohashRect = feature.properties.rectangle;
+        const geohashRect = feature.properties.rectangle;
         // get bounds from northEast[3] and southWest[1]
         // corners in geohash rectangle
-        let corners = [
+        const corners = [
           [geohashRect[3][0], geohashRect[3][1]],
           [geohashRect[1][0], geohashRect[1][1]]
         ];
diff --git a/src/ui/public/vislib/visualizations/marker_types/heatmap.js b/src/ui/public/vislib/visualizations/marker_types/heatmap.js
index a066295c4eb29..8f2de5dfbfaa8 100644
--- a/src/ui/public/vislib/visualizations/marker_types/heatmap.js
+++ b/src/ui/public/vislib/visualizations/marker_types/heatmap.js
@@ -4,7 +4,7 @@ import L from 'leaflet';
 import VislibVisualizationsMarkerTypesBaseMarkerProvider from 'ui/vislib/visualizations/marker_types/base_marker';
 export default function HeatmapMarkerFactory(Private) {
 
-  let BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
+  const BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
 
   /**
    * Map overlay: canvas layer with leaflet.heat plugin
@@ -15,7 +15,7 @@ export default function HeatmapMarkerFactory(Private) {
    */
   _.class(HeatmapMarker).inherits(BaseMarker);
   function HeatmapMarker(map, geoJson, params) {
-    let self = this;
+    const self = this;
     this._disableTooltips = false;
     HeatmapMarker.Super.apply(this, arguments);
 
@@ -36,8 +36,8 @@ export default function HeatmapMarkerFactory(Private) {
   HeatmapMarker.prototype.addLegend = _.noop;
 
   HeatmapMarker.prototype._createMarkerGroup = function (options) {
-    let max = _.get(this.geoJson, 'properties.allmax');
-    let points = this._dataToHeatArray(max);
+    const max = _.get(this.geoJson, 'properties.allmax');
+    const points = this._dataToHeatArray(max);
 
     this._markerGroup = L.heatLayer(points, options);
     this._fixTooltips();
@@ -45,8 +45,8 @@ export default function HeatmapMarkerFactory(Private) {
   };
 
   HeatmapMarker.prototype._fixTooltips = function () {
-    let self = this;
-    let debouncedMouseMoveLocation = _.debounce(mouseMoveLocation.bind(this), 15, {
+    const self = this;
+    const debouncedMouseMoveLocation = _.debounce(mouseMoveLocation.bind(this), 15, {
       'leading': true,
       'trailing': false
     });
@@ -66,7 +66,7 @@ export default function HeatmapMarkerFactory(Private) {
     }
 
     function mouseMoveLocation(e) {
-      let latlng = e.latlng;
+      const latlng = e.latlng;
 
       this.map.closePopup();
 
@@ -78,7 +78,7 @@ export default function HeatmapMarkerFactory(Private) {
       }
 
       // find nearest feature to event latlng
-      let feature = this._nearestFeature(latlng);
+      const feature = this._nearestFeature(latlng);
 
       // show tooltip if close enough to event latlng
       if (this._tooltipProximity(latlng, feature)) {
@@ -112,7 +112,7 @@ export default function HeatmapMarkerFactory(Private) {
    * @return nearestPoint {Leaflet latLng}
    */
   HeatmapMarker.prototype._nearestFeature = function (latLng) {
-    let self = this;
+    const self = this;
     let nearest;
 
     if (latLng.lng < -180 || latLng.lng > 180) {
@@ -120,8 +120,8 @@ export default function HeatmapMarkerFactory(Private) {
     }
 
     _.reduce(this.geoJson.features, function (distance, feature) {
-      let featureLatLng = self._getLatLng(feature);
-      let dist = latLng.distanceTo(featureLatLng);
+      const featureLatLng = self._getLatLng(feature);
+      const dist = latLng.distanceTo(featureLatLng);
 
       if (dist < distance) {
         nearest = feature;
@@ -146,30 +146,30 @@ export default function HeatmapMarkerFactory(Private) {
     if (!feature) return;
 
     let showTip = false;
-    let featureLatLng = this._getLatLng(feature);
+    const featureLatLng = this._getLatLng(feature);
 
     // zoomScale takes map zoom and returns proximity value for tooltip display
     // domain (input values) is map zoom (min 1 and max 18)
     // range (output values) is distance in meters
     // used to compare proximity of event latlng to feature latlng
-    let zoomScale = d3.scale.linear()
+    const zoomScale = d3.scale.linear()
     .domain([1, 4, 7, 10, 13, 16, 18])
     .range([1000000, 300000, 100000, 15000, 2000, 150, 50]);
 
-    let proximity = zoomScale(this.map.getZoom());
-    let distance = latlng.distanceTo(featureLatLng);
+    const proximity = zoomScale(this.map.getZoom());
+    const distance = latlng.distanceTo(featureLatLng);
 
     // maxLngDif is max difference in longitudes
     // to prevent feature tooltip from appearing 360°
     // away from event latlng
-    let maxLngDif = 40;
-    let lngDif = Math.abs(latlng.lng - featureLatLng.lng);
+    const maxLngDif = 40;
+    const lngDif = Math.abs(latlng.lng - featureLatLng.lng);
 
     if (distance < proximity && lngDif < maxLngDif) {
       showTip = true;
     }
 
-    let testScale = d3.scale.pow().exponent(0.2)
+    const testScale = d3.scale.pow().exponent(0.2)
     .domain([1, 18])
     .range([1500000, 50]);
     return showTip;
@@ -186,12 +186,12 @@ export default function HeatmapMarkerFactory(Private) {
    * @return {Array}
    */
   HeatmapMarker.prototype._dataToHeatArray = function (max) {
-    let self = this;
-    let mapData = this.geoJson;
+    const self = this;
+    const mapData = this.geoJson;
 
     return this.geoJson.features.map(function (feature) {
-      let lat = feature.properties.center[0];
-      let lng = feature.properties.center[1];
+      const lat = feature.properties.center[0];
+      const lng = feature.properties.center[1];
       let heatIntensity;
 
       if (!self._attr.heatNormalizeData) {
diff --git a/src/ui/public/vislib/visualizations/marker_types/scaled_circles.js b/src/ui/public/vislib/visualizations/marker_types/scaled_circles.js
index 8a0c84841dc7b..94b239e062ad1 100644
--- a/src/ui/public/vislib/visualizations/marker_types/scaled_circles.js
+++ b/src/ui/public/vislib/visualizations/marker_types/scaled_circles.js
@@ -3,7 +3,7 @@ import L from 'leaflet';
 import VislibVisualizationsMarkerTypesBaseMarkerProvider from 'ui/vislib/visualizations/marker_types/base_marker';
 export default function ScaledCircleMarkerFactory(Private) {
 
-  let BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
+  const BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
 
   /**
    * Map overlay: circle markers that are scaled to illustrate values
@@ -14,16 +14,16 @@ export default function ScaledCircleMarkerFactory(Private) {
    */
   _.class(ScaledCircleMarker).inherits(BaseMarker);
   function ScaledCircleMarker(map, geoJson, params) {
-    let self = this;
+    const self = this;
     ScaledCircleMarker.Super.apply(this, arguments);
 
     // multiplier to reduce size of all circles
-    let scaleFactor = 0.6;
+    const scaleFactor = 0.6;
 
     this._createMarkerGroup({
       pointToLayer: function (feature, latlng) {
-        let value = feature.properties.value;
-        let scaledRadius = self._radiusScale(value) * scaleFactor;
+        const value = feature.properties.value;
+        const scaledRadius = self._radiusScale(value) * scaleFactor;
         return L.circleMarker(latlng).setRadius(scaledRadius);
       }
     });
@@ -38,17 +38,17 @@ export default function ScaledCircleMarkerFactory(Private) {
    * @return {Number}
    */
   ScaledCircleMarker.prototype._radiusScale = function (value) {
-    let precisionBiasBase = 5;
-    let precisionBiasNumerator = 200;
-    let zoom = this.map.getZoom();
-    let maxValue = this.geoJson.properties.allmax;
-    let precision = _.max(this.geoJson.features.map(function (feature) {
+    const precisionBiasBase = 5;
+    const precisionBiasNumerator = 200;
+    const zoom = this.map.getZoom();
+    const maxValue = this.geoJson.properties.allmax;
+    const precision = _.max(this.geoJson.features.map(function (feature) {
       return String(feature.properties.geohash).length;
     }));
 
-    let pct = Math.abs(value) / Math.abs(maxValue);
-    let zoomRadius = 0.5 * Math.pow(2, zoom);
-    let precisionScale = precisionBiasNumerator / Math.pow(precisionBiasBase, precision);
+    const pct = Math.abs(value) / Math.abs(maxValue);
+    const zoomRadius = 0.5 * Math.pow(2, zoom);
+    const precisionScale = precisionBiasNumerator / Math.pow(precisionBiasBase, precision);
 
     // square root value percentage
     return Math.pow(pct, 0.5) * zoomRadius * precisionScale;
diff --git a/src/ui/public/vislib/visualizations/marker_types/shaded_circles.js b/src/ui/public/vislib/visualizations/marker_types/shaded_circles.js
index c873f2f9c1613..c34ea909749f9 100644
--- a/src/ui/public/vislib/visualizations/marker_types/shaded_circles.js
+++ b/src/ui/public/vislib/visualizations/marker_types/shaded_circles.js
@@ -3,7 +3,7 @@ import L from 'leaflet';
 import VislibVisualizationsMarkerTypesBaseMarkerProvider from 'ui/vislib/visualizations/marker_types/base_marker';
 export default function ShadedCircleMarkerFactory(Private) {
 
-  let BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
+  const BaseMarker = Private(VislibVisualizationsMarkerTypesBaseMarkerProvider);
 
   /**
    * Map overlay: circle markers that are shaded to illustrate values
@@ -14,19 +14,19 @@ export default function ShadedCircleMarkerFactory(Private) {
    */
   _.class(ShadedCircleMarker).inherits(BaseMarker);
   function ShadedCircleMarker(map, geoJson, params) {
-    let self = this;
+    const self = this;
     ShadedCircleMarker.Super.apply(this, arguments);
 
     // super min and max from all chart data
-    let min = this.geoJson.properties.allmin;
-    let max = this.geoJson.properties.allmax;
+    const min = this.geoJson.properties.allmin;
+    const max = this.geoJson.properties.allmax;
 
     // multiplier to reduce size of all circles
-    let scaleFactor = 0.8;
+    const scaleFactor = 0.8;
 
     this._createMarkerGroup({
       pointToLayer: function (feature, latlng) {
-        let radius = self._geohashMinDistance(feature) * scaleFactor;
+        const radius = self._geohashMinDistance(feature) * scaleFactor;
         return L.circle(latlng, radius);
       }
     });
@@ -41,8 +41,8 @@ export default function ShadedCircleMarkerFactory(Private) {
    * @return {Number}
    */
   ShadedCircleMarker.prototype._geohashMinDistance = function (feature) {
-    let centerPoint = _.get(feature, 'properties.center');
-    let geohashRect = _.get(feature, 'properties.rectangle');
+    const centerPoint = _.get(feature, 'properties.center');
+    const geohashRect = _.get(feature, 'properties.rectangle');
 
     // centerPoint is an array of [lat, lng]
     // geohashRect is the 4 corners of the geoHash rectangle
@@ -50,16 +50,16 @@ export default function ShadedCircleMarkerFactory(Private) {
     //   clockwise, each value being an array of [lat, lng]
 
     // center lat and southeast lng
-    let east   = L.latLng([centerPoint[0], geohashRect[2][1]]);
+    const east   = L.latLng([centerPoint[0], geohashRect[2][1]]);
     // southwest lat and center lng
-    let north  = L.latLng([geohashRect[3][0], centerPoint[1]]);
+    const north  = L.latLng([geohashRect[3][0], centerPoint[1]]);
 
     // get latLng of geohash center point
-    let center = L.latLng([centerPoint[0], centerPoint[1]]);
+    const center = L.latLng([centerPoint[0], centerPoint[1]]);
 
     // get smallest radius at center of geohash grid rectangle
-    let eastRadius  = Math.floor(center.distanceTo(east));
-    let northRadius = Math.floor(center.distanceTo(north));
+    const eastRadius  = Math.floor(center.distanceTo(east));
+    const northRadius = Math.floor(center.distanceTo(north));
     return _.min([eastRadius, northRadius]);
   };
 
diff --git a/src/ui/public/vislib/visualizations/pie_chart.js b/src/ui/public/vislib/visualizations/pie_chart.js
index b18c0820942c1..71f620587bc59 100644
--- a/src/ui/public/vislib/visualizations/pie_chart.js
+++ b/src/ui/public/vislib/visualizations/pie_chart.js
@@ -5,7 +5,7 @@ import errors from 'ui/errors';
 import VislibVisualizationsChartProvider from 'ui/vislib/visualizations/_chart';
 export default function PieChartFactory(Private) {
 
-  let Chart = Private(VislibVisualizationsChartProvider);
+  const Chart = Private(VislibVisualizationsChartProvider);
 
   /**
    * Pie Chart Visualization
@@ -24,7 +24,7 @@ export default function PieChartFactory(Private) {
     }
     PieChart.Super.apply(this, arguments);
 
-    let charts = this.handler.data.getVisData();
+    const charts = this.handler.data.getVisData();
     this._validatePieData(charts);
 
     this._attr = _.defaults(handler._attr || {}, {
@@ -37,7 +37,7 @@ export default function PieChartFactory(Private) {
    * If so, an error is thrown.
    */
   PieChart.prototype._validatePieData = function (charts) {
-    let isAllZeros = charts.every(function (chart) {
+    const isAllZeros = charts.every(function (chart) {
       return chart.slices.children.length === 0;
     });
 
@@ -52,7 +52,7 @@ export default function PieChartFactory(Private) {
    * @returns {D3.Selection} SVG path with event listeners attached
    */
   PieChart.prototype.addPathEvents = function (element) {
-    let events = this.events;
+    const events = this.events;
 
     return element
       .call(events.addHoverEvent())
@@ -64,11 +64,11 @@ export default function PieChartFactory(Private) {
     (function assignPercentages(slices) {
       if (slices.sumOfChildren != null) return;
 
-      let parent = slices;
-      let children = parent.children;
-      let parentPercent = parent.percentOfParent;
+      const parent = slices;
+      const children = parent.children;
+      const parentPercent = parent.percentOfParent;
 
-      let sum = parent.sumOfChildren = Math.abs(children.reduce(function (sum, child) {
+      const sum = parent.sumOfChildren = Math.abs(children.reduce(function (sum, child) {
         return sum + Math.abs(child.size);
       }, 0));
 
@@ -98,24 +98,24 @@ export default function PieChartFactory(Private) {
    * @returns {D3.Selection} SVG with paths attached
    */
   PieChart.prototype.addPath = function (width, height, svg, slices) {
-    let self = this;
-    let marginFactor = 0.95;
-    let isDonut = self._attr.isDonut;
-    let radius = (Math.min(width, height) / 2) * marginFactor;
-    let color = self.handler.data.getPieColorFunc();
-    let tooltip = self.tooltip;
-    let isTooltip = self._attr.addTooltip;
-
-    let partition = d3.layout.partition()
+    const self = this;
+    const marginFactor = 0.95;
+    const isDonut = self._attr.isDonut;
+    const radius = (Math.min(width, height) / 2) * marginFactor;
+    const color = self.handler.data.getPieColorFunc();
+    const tooltip = self.tooltip;
+    const isTooltip = self._attr.addTooltip;
+
+    const partition = d3.layout.partition()
     .sort(null)
     .value(function (d) {
       return d.percentOfParent * 100;
     });
-    let x = d3.scale.linear()
+    const x = d3.scale.linear()
     .range([0, 2 * Math.PI]);
-    let y = d3.scale.sqrt()
+    const y = d3.scale.sqrt()
     .range([0, radius]);
-    let arc = d3.svg.arc()
+    const arc = d3.svg.arc()
     .startAngle(function (d) {
       return Math.max(0, Math.min(2 * Math.PI, x(d.x)));
     })
@@ -135,7 +135,7 @@ export default function PieChartFactory(Private) {
       return Math.max(0, y(d.y + d.dy));
     });
 
-    let path = svg
+    const path = svg
     .datum(slices)
     .selectAll('path')
     .data(partition.nodes)
@@ -161,8 +161,8 @@ export default function PieChartFactory(Private) {
   };
 
   PieChart.prototype._validateContainerSize = function (width, height) {
-    let minWidth = 20;
-    let minHeight = 20;
+    const minWidth = 20;
+    const minHeight = 20;
 
     if (width <= minWidth || height <= minHeight) {
       throw new errors.ContainerTooSmall();
@@ -176,28 +176,27 @@ export default function PieChartFactory(Private) {
    * @returns {Function} Creates the pie chart
    */
   PieChart.prototype.draw = function () {
-    let self = this;
+    const self = this;
 
     return function (selection) {
       selection.each(function (data) {
-        let slices = data.slices;
-        let div = d3.select(this);
-        let width = $(this).width();
-        let height = $(this).height();
-        let path;
+        const slices = data.slices;
+        const div = d3.select(this);
+        const width = $(this).width();
+        const height = $(this).height();
 
         if (!slices.children.length) return;
 
         self.convertToPercentage(slices);
         self._validateContainerSize(width, height);
 
-        let svg = div.append('svg')
+        const svg = div.append('svg')
         .attr('width', width)
         .attr('height', height)
         .append('g')
         .attr('transform', 'translate(' + width / 2 + ',' + height / 2 + ')');
 
-        path = self.addPath(width, height, svg, slices);
+        const path = self.addPath(width, height, svg, slices);
         self.addPathEvents(path);
 
         return svg;
diff --git a/src/ui/public/vislib/visualizations/tile_map.js b/src/ui/public/vislib/visualizations/tile_map.js
index bc3d3bab83a75..2975d414220ae 100644
--- a/src/ui/public/vislib/visualizations/tile_map.js
+++ b/src/ui/public/vislib/visualizations/tile_map.js
@@ -5,8 +5,8 @@ import VislibVisualizationsChartProvider from 'ui/vislib/visualizations/_chart';
 import VislibVisualizationsMapProvider from 'ui/vislib/visualizations/_map';
 export default function TileMapFactory(Private) {
 
-  let Chart = Private(VislibVisualizationsChartProvider);
-  let TileMapMap = Private(VislibVisualizationsMapProvider);
+  const Chart = Private(VislibVisualizationsChartProvider);
+  const TileMapMap = Private(VislibVisualizationsMapProvider);
 
   /**
    * Tile Map Visualization: renders maps
@@ -41,7 +41,7 @@ export default function TileMapFactory(Private) {
    * @return {Function} - function to add a map to a selection
    */
   TileMap.prototype.draw = function () {
-    let self = this;
+    const self = this;
 
     // clean up old maps
     self.destroy();
@@ -86,7 +86,7 @@ export default function TileMapFactory(Private) {
    */
   TileMap.prototype._appendGeoExtents = function () {
     // add allmin and allmax to geoJson
-    let geoMinMax = this.handler.data.getGeoExtents();
+    const geoMinMax = this.handler.data.getGeoExtents();
     this.geoJson.properties.allmin = geoMinMax.min;
     this.geoJson.properties.allmax = geoMinMax.max;
   };
diff --git a/src/ui/public/vislib/visualizations/time_marker.js b/src/ui/public/vislib/visualizations/time_marker.js
index 19fbc2fb9ee52..5fb8d087ca6ad 100644
--- a/src/ui/public/vislib/visualizations/time_marker.js
+++ b/src/ui/public/vislib/visualizations/time_marker.js
@@ -7,7 +7,7 @@ export default function TimeMarkerFactory() {
       return new TimeMarker(times, xScale, height);
     }
 
-    let currentTimeArr = [{
+    const currentTimeArr = [{
       'time': new Date().getTime(),
       'class': 'time-marker',
       'color': '#c80000',
@@ -29,14 +29,14 @@ export default function TimeMarkerFactory() {
   }
 
   TimeMarker.prototype._isTimeBasedChart = function (selection) {
-    let data = selection.data();
+    const data = selection.data();
     return data.every(function (datum) {
       return (datum.ordered && datum.ordered.date);
     });
   };
 
   TimeMarker.prototype.render = function (selection) {
-    let self = this;
+    const self = this;
 
     // return if not time based chart
     if (!self._isTimeBasedChart(selection)) return;
diff --git a/src/ui/public/vislib_vis_type/__tests__/_build_chart_data.js b/src/ui/public/vislib_vis_type/__tests__/_build_chart_data.js
index 44628c2b39de5..009db2d065b8f 100644
--- a/src/ui/public/vislib_vis_type/__tests__/_build_chart_data.js
+++ b/src/ui/public/vislib_vis_type/__tests__/_build_chart_data.js
@@ -23,14 +23,14 @@ describe('renderbot#buildChartData', function () {
 
   describe('for hierarchical vis', function () {
     it('defers to hierarchical aggResponse converter', function () {
-      let football = {};
-      let renderbot = {
+      const football = {};
+      const renderbot = {
         vis: {
           isHierarchical: _.constant(true)
         }
       };
 
-      let stub = sinon.stub(aggResponse, 'hierarchical').returns(football);
+      const stub = sinon.stub(aggResponse, 'hierarchical').returns(football);
       expect(buildChartData.call(renderbot, football)).to.be(football);
       expect(stub).to.have.property('callCount', 1);
       expect(stub.firstCall.args[0]).to.be(renderbot.vis);
@@ -40,14 +40,14 @@ describe('renderbot#buildChartData', function () {
 
   describe('for point plot', function () {
     it('calls tabify to simplify the data into a table', function () {
-      let renderbot = {
+      const renderbot = {
         vis: {
           isHierarchical: _.constant(false)
         }
       };
-      let football = { tables: [], hits: { total: 1 } };
+      const football = { tables: [], hits: { total: 1 } };
 
-      let stub = sinon.stub(aggResponse, 'tabify').returns(football);
+      const stub = sinon.stub(aggResponse, 'tabify').returns(football);
       expect(buildChartData.call(renderbot, football)).to.eql({ rows: [], hits: 1 });
       expect(stub).to.have.property('callCount', 1);
       expect(stub.firstCall.args[0]).to.be(renderbot.vis);
@@ -55,8 +55,8 @@ describe('renderbot#buildChartData', function () {
     });
 
     it('returns a single chart if the tabify response contains only a single table', function () {
-      let chart = { hits: 1, rows: [], columns: [] };
-      let renderbot = {
+      const chart = { hits: 1, rows: [], columns: [] };
+      const renderbot = {
         vis: {
           isHierarchical: _.constant(false),
           type: {
@@ -64,20 +64,20 @@ describe('renderbot#buildChartData', function () {
           }
         }
       };
-      let esResp = { hits: { total: 1 } };
-      let tabbed = { tables: [ new Table() ] };
+      const esResp = { hits: { total: 1 } };
+      const tabbed = { tables: [ new Table() ] };
 
       sinon.stub(aggResponse, 'tabify').returns(tabbed);
       expect(buildChartData.call(renderbot, esResp)).to.eql(chart);
     });
 
     it('converts table groups into rows/columns wrappers for charts', function () {
-      let chart = { hits: 1, rows: [], columns: [] };
-      let converter = sinon.stub().returns('chart');
-      let esResp = { hits: { total: 1 } };
-      let tables = [new Table(), new Table(), new Table(), new Table()];
+      const chart = { hits: 1, rows: [], columns: [] };
+      const converter = sinon.stub().returns('chart');
+      const esResp = { hits: { total: 1 } };
+      const tables = [new Table(), new Table(), new Table(), new Table()];
 
-      let renderbot = {
+      const renderbot = {
         vis: {
           isHierarchical: _.constant(false),
           type: {
@@ -86,7 +86,7 @@ describe('renderbot#buildChartData', function () {
         }
       };
 
-      let tabify = sinon.stub(aggResponse, 'tabify').returns({
+      const tabify = sinon.stub(aggResponse, 'tabify').returns({
         tables: [
           {
             aggConfig: { params: { row: true } },
@@ -117,7 +117,7 @@ describe('renderbot#buildChartData', function () {
         ]
       });
 
-      let chartData = buildChartData.call(renderbot, esResp);
+      const chartData = buildChartData.call(renderbot, esResp);
 
       // verify tables were converted
       expect(converter).to.have.property('callCount', 4);
diff --git a/src/ui/public/vislib_vis_type/__tests__/_vislib_renderbot.js b/src/ui/public/vislib_vis_type/__tests__/_vislib_renderbot.js
index b70e61001a9e4..23d62ad61805d 100644
--- a/src/ui/public/vislib_vis_type/__tests__/_vislib_renderbot.js
+++ b/src/ui/public/vislib_vis_type/__tests__/_vislib_renderbot.js
@@ -16,7 +16,7 @@ describe('renderbot', function exportWrapper() {
   let VislibRenderbot;
   let persistedState;
   let normalizeChartData;
-  let mockVisType = {
+  const mockVisType = {
     name: 'test'
   };
 
@@ -36,8 +36,8 @@ describe('renderbot', function exportWrapper() {
   beforeEach(init);
 
   describe('creation', function () {
-    let vis = { type: mockVisType };
-    let $el = 'element';
+    const vis = { type: mockVisType };
+    const $el = 'element';
     let createVisStub;
     let renderbot;
 
@@ -56,7 +56,7 @@ describe('renderbot', function exportWrapper() {
   });
 
   describe('_createVis', function () {
-    let vis = {
+    const vis = {
       type: mockVisType,
       listeners: {
         'test': _.noop,
@@ -64,7 +64,7 @@ describe('renderbot', function exportWrapper() {
         'test3': _.noop
       }
     };
-    let $el = $('<div>testing</div>');
+    const $el = $('<div>testing</div>');
     let listenerSpy;
     let renderbot;
 
@@ -82,15 +82,15 @@ describe('renderbot', function exportWrapper() {
   });
 
   describe('param update', function () {
-    let params = { one: 'fish', two: 'fish' };
-    let vis = {
+    const params = { one: 'fish', two: 'fish' };
+    const vis = {
       type: _.defaults({
         params: {
           defaults: params
         }
       }, mockVisType)
     };
-    let $el = $('<div>testing</div>');
+    const $el = $('<div>testing</div>');
     let createVisSpy;
     let getParamsStub;
     let renderbot;
@@ -119,20 +119,20 @@ describe('renderbot', function exportWrapper() {
   });
 
   describe('render', function () {
-    let vis = { type: mockVisType, isHierarchical: _.constant(false) };
-    let $el = $('<div>testing</div>');
-    let stubs = {};
+    const vis = { type: mockVisType, isHierarchical: _.constant(false) };
+    const $el = $('<div>testing</div>');
+    const stubs = {};
 
     beforeEach(function () {
       sinon.stub(VislibRenderbot.prototype, '_getVislibParams', _.constant({}));
     });
 
     it('should use #buildChartData', function () {
-      let renderbot = new VislibRenderbot(vis, $el, persistedState);
+      const renderbot = new VislibRenderbot(vis, $el, persistedState);
 
-      let football = {};
-      let buildStub = sinon.stub(renderbot, 'buildChartData', _.constant(football));
-      let renderStub = sinon.stub(renderbot.vislibVis, 'render');
+      const football = {};
+      const buildStub = sinon.stub(renderbot, 'buildChartData', _.constant(football));
+      const renderStub = sinon.stub(renderbot.vislibVis, 'render');
 
       renderbot.render('flat data', persistedState);
       expect(renderStub.callCount).to.be(1);
@@ -142,7 +142,7 @@ describe('renderbot', function exportWrapper() {
   });
 
   describe('destroy', function () {
-    let vis = {
+    const vis = {
       type: mockVisType,
       listeners: {
         'test': _.noop,
@@ -150,7 +150,7 @@ describe('renderbot', function exportWrapper() {
         'test3': _.noop
       }
     };
-    let $el = $('<div>testing</div>');
+    const $el = $('<div>testing</div>');
     let listenerSpy;
     let renderbot;
 
@@ -167,7 +167,7 @@ describe('renderbot', function exportWrapper() {
     });
 
     it('should destroy the vis', function () {
-      let spy = sinon.spy(renderbot.vislibVis, 'destroy');
+      const spy = sinon.spy(renderbot.vislibVis, 'destroy');
       renderbot.destroy();
       expect(spy.callCount).to.be(1);
     });
diff --git a/src/ui/public/vislib_vis_type/build_chart_data.js b/src/ui/public/vislib_vis_type/build_chart_data.js
index 84f2fc5875f42..6ee282beeb620 100644
--- a/src/ui/public/vislib_vis_type/build_chart_data.js
+++ b/src/ui/public/vislib_vis_type/build_chart_data.js
@@ -2,18 +2,18 @@ import AggResponseIndexProvider from 'ui/agg_response/index';
 import AggResponseTabifyTableProvider from 'ui/agg_response/tabify/_table';
 
 export default function VislibVisBuildChartData(Private) {
-  let aggResponse = Private(AggResponseIndexProvider);
-  let Table = Private(AggResponseTabifyTableProvider);
+  const aggResponse = Private(AggResponseIndexProvider);
+  const Table = Private(AggResponseTabifyTableProvider);
 
   return function (esResponse) {
-    let vis = this.vis;
+    const vis = this.vis;
 
     if (vis.isHierarchical()) {
       // the hierarchical converter is very self-contained (woot!)
       return aggResponse.hierarchical(vis, esResponse);
     }
 
-    let tableGroup = aggResponse.tabify(vis, esResponse, {
+    const tableGroup = aggResponse.tabify(vis, esResponse, {
       canSplit: true,
       asAggConfigResults: true
     });
@@ -31,11 +31,11 @@ export default function VislibVisBuildChartData(Private) {
   };
 
   function convertTableGroup(vis, tableGroup) {
-    let tables = tableGroup.tables;
-    let firstChild = tables[0];
+    const tables = tableGroup.tables;
+    const firstChild = tables[0];
     if (firstChild instanceof Table) {
 
-      let chart = convertTable(vis, firstChild);
+      const chart = convertTable(vis, firstChild);
       // if chart is within a split, assign group title to its label
       if (tableGroup.$parent) {
         chart.label = tableGroup.title;
@@ -44,13 +44,13 @@ export default function VislibVisBuildChartData(Private) {
     }
 
     if (!tables.length) return;
-    let out = {};
+    const out = {};
     let outList;
 
     tables.forEach(function (table) {
       if (!outList) {
-        let aggConfig = table.aggConfig;
-        let direction = aggConfig.params.row ? 'rows' : 'columns';
+        const aggConfig = table.aggConfig;
+        const direction = aggConfig.params.row ? 'rows' : 'columns';
         outList = out[direction] = [];
       }
 
diff --git a/src/ui/public/vislib_vis_type/vislib_renderbot.js b/src/ui/public/vislib_vis_type/vislib_renderbot.js
index 1cbbf1a424c21..318f662b8d81c 100644
--- a/src/ui/public/vislib_vis_type/vislib_renderbot.js
+++ b/src/ui/public/vislib_vis_type/vislib_renderbot.js
@@ -3,9 +3,9 @@ import VislibProvider from 'ui/vislib';
 import VisRenderbotProvider from 'ui/vis/renderbot';
 import VislibVisTypeBuildChartDataProvider from 'ui/vislib_vis_type/build_chart_data';
 module.exports = function VislibRenderbotFactory(Private) {
-  let vislib = Private(VislibProvider);
-  let Renderbot = Private(VisRenderbotProvider);
-  let buildChartData = Private(VislibVisTypeBuildChartDataProvider);
+  const vislib = Private(VislibProvider);
+  const Renderbot = Private(VisRenderbotProvider);
+  const buildChartData = Private(VislibVisTypeBuildChartDataProvider);
 
   _.class(VislibRenderbot).inherits(Renderbot);
   function VislibRenderbot(vis, $el, uiState) {
@@ -14,7 +14,7 @@ module.exports = function VislibRenderbotFactory(Private) {
   }
 
   VislibRenderbot.prototype._createVis = function () {
-    let self = this;
+    const self = this;
 
     if (self.vislibVis) self.destroy();
 
@@ -29,7 +29,7 @@ module.exports = function VislibRenderbotFactory(Private) {
   };
 
   VislibRenderbot.prototype._getVislibParams = function () {
-    let self = this;
+    const self = this;
 
     return _.assign(
       {},
@@ -50,9 +50,9 @@ module.exports = function VislibRenderbotFactory(Private) {
   };
 
   VislibRenderbot.prototype.destroy = function () {
-    let self = this;
+    const self = this;
 
-    let vislibVis = self.vislibVis;
+    const vislibVis = self.vislibVis;
 
     _.forOwn(self.vis.listeners, function (listener, event) {
       vislibVis.off(event, listener);
@@ -62,10 +62,10 @@ module.exports = function VislibRenderbotFactory(Private) {
   };
 
   VislibRenderbot.prototype.updateParams = function () {
-    let self = this;
+    const self = this;
 
     // get full vislib params object
-    let newParams = self._getVislibParams();
+    const newParams = self._getVislibParams();
 
     // if there's been a change, replace the vis
     if (!_.isEqual(newParams, self.vislibParams)) self._createVis();
diff --git a/src/ui/public/vislib_vis_type/vislib_vis_type.js b/src/ui/public/vislib_vis_type/vislib_vis_type.js
index a18977bc2ca73..867be2f02bc40 100644
--- a/src/ui/public/vislib_vis_type/vislib_vis_type.js
+++ b/src/ui/public/vislib_vis_type/vislib_vis_type.js
@@ -9,10 +9,10 @@ import AggResponsePointSeriesPointSeriesProvider from 'ui/agg_response/point_ser
 import VislibVisTypeVislibRenderbotProvider from 'ui/vislib_vis_type/vislib_renderbot';
 export default function VislibVisTypeFactory(Private) {
 
-  let VisTypeSchemas = Private(VisSchemasProvider);
-  let VisType = Private(VisVisTypeProvider);
-  let pointSeries = Private(AggResponsePointSeriesPointSeriesProvider);
-  let VislibRenderbot = Private(VislibVisTypeVislibRenderbotProvider);
+  const VisTypeSchemas = Private(VisSchemasProvider);
+  const VisType = Private(VisVisTypeProvider);
+  const pointSeries = Private(AggResponsePointSeriesPointSeriesProvider);
+  const VislibRenderbot = Private(VislibVisTypeVislibRenderbotProvider);
 
 
   _.class(VislibVisType).inherits(VisType);
diff --git a/src/ui/public/visualize/spy.js b/src/ui/public/visualize/spy.js
index e8df7aa336b80..b299f700e0ad4 100644
--- a/src/ui/public/visualize/spy.js
+++ b/src/ui/public/visualize/spy.js
@@ -7,15 +7,15 @@ uiModules
   .get('app/visualize')
   .directive('visualizeSpy', function (Private, $compile) {
 
-    let spyModes = Private(RegistrySpyModesProvider);
-    let defaultMode = spyModes.inOrder[0].name;
+    const spyModes = Private(RegistrySpyModesProvider);
+    const defaultMode = spyModes.inOrder[0].name;
 
     return {
       restrict: 'E',
       template: spyTemplate,
       link: function ($scope, $el) {
         let currentSpy;
-        let $container = $el.find('.visualize-spy-container');
+        const $container = $el.find('.visualize-spy-container');
         let fullPageSpy = _.get($scope.spy, 'mode.fill', false);
         $scope.modes = spyModes;
         $scope.spy.params = $scope.spy.params || {};
@@ -30,8 +30,8 @@ uiModules
           };
         }
 
-        let renderSpy = function (spyName) {
-          let newMode = $scope.modes.byName[spyName];
+        const renderSpy = function (spyName) {
+          const newMode = $scope.modes.byName[spyName];
 
           // clear the current value
           if (currentSpy) {
@@ -57,7 +57,7 @@ uiModules
         };
 
         $scope.toggleDisplay = function () {
-          let modeName = _.get($scope.spy, 'mode.name');
+          const modeName = _.get($scope.spy, 'mode.name');
           $scope.setSpyMode(modeName ? null : defaultMode);
         };
 
@@ -74,7 +74,7 @@ uiModules
 
         if ($scope.uiState) {
           // sync external uiState changes
-          let syncUIState = () => $scope.spy.mode = $scope.uiState.get('spy.mode');
+          const syncUIState = () => $scope.spy.mode = $scope.uiState.get('spy.mode');
           $scope.uiState.on('change', syncUIState);
           $scope.$on('$destroy', () => $scope.uiState.off('change', syncUIState));
         }
@@ -85,7 +85,7 @@ uiModules
           'spy.mode.fill'
         ], function (newVals, oldVals) {
           // update the ui state, but only if it really changes
-          let changedVals = newVals.filter((val) => !_.isUndefined(val)).length > 0;
+          const changedVals = newVals.filter((val) => !_.isUndefined(val)).length > 0;
           if (changedVals && !_.isEqual(newVals, oldVals)) {
             if ($scope.uiState) $scope.uiState.set('spy.mode', $scope.spy.mode);
           }
diff --git a/src/ui/public/visualize/visualize.js b/src/ui/public/visualize/visualize.js
index c02f46c96b5d3..bb0a7bab20bef 100644
--- a/src/ui/public/visualize/visualize.js
+++ b/src/ui/public/visualize/visualize.js
@@ -13,9 +13,9 @@ uiModules
 .directive('visualize', function (Notifier, SavedVis, indexPatterns, Private, config, $timeout) {
 
 
-  let visTypes = Private(RegistryVisTypesProvider);
+  const visTypes = Private(RegistryVisTypesProvider);
 
-  let notify = new Notifier({
+  const notify = new Notifier({
     location: 'Visualize'
   });
 
@@ -39,19 +39,19 @@ uiModules
 
       function getter(selector) {
         return function () {
-          let $sel = $el.find(selector);
+          const $sel = $el.find(selector);
           if ($sel.size()) return $sel;
         };
       }
 
-      let getVisEl = getter('.visualize-chart');
-      let getVisContainer = getter('.vis-container');
+      const getVisEl = getter('.visualize-chart');
+      const getVisContainer = getter('.vis-container');
 
       // Show no results message when isZeroHits is true and it requires search
       $scope.showNoResultsMessage = function () {
-        let requiresSearch = _.get($scope, 'vis.type.requiresSearch');
-        let isZeroHits = _.get($scope,'esResp.hits.total') === 0;
-        let shouldShowMessage = !_.get($scope, 'vis.params.handleNoResults');
+        const requiresSearch = _.get($scope, 'vis.type.requiresSearch');
+        const isZeroHits = _.get($scope,'esResp.hits.total') === 0;
+        const shouldShowMessage = !_.get($scope, 'vis.params.handleNoResults');
 
         return Boolean(requiresSearch && isZeroHits && shouldShowMessage);
       };
@@ -70,9 +70,9 @@ uiModules
       $scope.spy = {};
       $scope.spy.mode = ($scope.uiState) ? $scope.uiState.get('spy.mode', {}) : {};
 
-      let applyClassNames = function () {
-        let $visEl = getVisContainer();
-        let fullSpy = ($scope.spy.mode && ($scope.spy.mode.fill || $scope.fullScreenSpy));
+      const applyClassNames = function () {
+        const $visEl = getVisContainer();
+        const fullSpy = ($scope.spy.mode && ($scope.spy.mode.fill || $scope.fullScreenSpy));
 
         $visEl.toggleClass('spy-only', Boolean(fullSpy));
 
@@ -85,8 +85,8 @@ uiModules
 
       // we need to wait for some watchers to fire at least once
       // before we are "ready", this manages that
-      let prereq = (function () {
-        let fns = [];
+      const prereq = (function () {
+        const fns = [];
 
         return function register(fn) {
           fns.push(fn);
@@ -104,14 +104,14 @@ uiModules
         };
       }());
 
-      let loadingDelay = config.get('visualization:loadingDelay');
+      const loadingDelay = config.get('visualization:loadingDelay');
       $scope.loadingStyle = {
         '-webkit-transition-delay': loadingDelay,
         'transition-delay': loadingDelay
       };
 
       function shouldHaveFullSpy() {
-        let $visEl = getVisEl();
+        const $visEl = getVisEl();
         if (!$visEl) return;
 
         return ($visEl.height() < minVisChartHeight)
@@ -128,7 +128,7 @@ uiModules
       });
 
       $scope.$watch('vis', prereq(function (vis, oldVis) {
-        let $visEl = getVisEl();
+        const $visEl = getVisEl();
         if (!$visEl) return;
 
         if (!attr.editableVis) {
diff --git a/src/ui/public/visualize/visualize_legend.js b/src/ui/public/visualize/visualize_legend.js
index fa03abe422a56..e9d92642e0df8 100644
--- a/src/ui/public/visualize/visualize_legend.js
+++ b/src/ui/public/visualize/visualize_legend.js
@@ -11,16 +11,16 @@ import uiModules from 'ui/modules';
 
 uiModules.get('kibana')
 .directive('visualizeLegend', function (Private, getAppState) {
-  let Data = Private(VislibLibDataProvider);
-  let colorPalette = Private(VislibComponentsColorColorProvider);
-  let filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
+  const Data = Private(VislibLibDataProvider);
+  const colorPalette = Private(VislibComponentsColorColorProvider);
+  const filterBarClickHandler = Private(FilterBarFilterBarClickHandlerProvider);
 
   return {
     restrict: 'E',
     template: html,
     link: function ($scope, $elem) {
-      let $state = getAppState();
-      let clickHandler = filterBarClickHandler($state);
+      const $state = getAppState();
+      const clickHandler = filterBarClickHandler($state);
       $scope.open = $scope.uiState.get('vis.legendOpen', true);
 
       $scope.$watch('renderbot.chartData', function (data) {
@@ -30,29 +30,29 @@ uiModules.get('kibana')
       });
 
       $scope.highlight = function (event) {
-        let el = event.currentTarget;
-        let handler = $scope.renderbot.vislibVis.handler;
+        const el = event.currentTarget;
+        const handler = $scope.renderbot.vislibVis.handler;
         if (!handler) return;
         handler.highlight.call(el, handler.el);
       };
 
       $scope.unhighlight = function (event) {
-        let el = event.currentTarget;
-        let handler = $scope.renderbot.vislibVis.handler;
+        const el = event.currentTarget;
+        const handler = $scope.renderbot.vislibVis.handler;
         if (!handler) return;
         handler.unHighlight.call(el, handler.el);
       };
 
       $scope.setColor = function (label, color) {
-        let colors = $scope.uiState.get('vis.colors') || {};
+        const colors = $scope.uiState.get('vis.colors') || {};
         colors[label] = color;
         $scope.uiState.set('vis.colors', colors);
         refresh();
       };
 
       $scope.toggleLegend = function () {
-        let bwcAddLegend = $scope.renderbot.vislibVis._attr.addLegend;
-        let bwcLegendStateDefault = bwcAddLegend == null ? true : bwcAddLegend;
+        const bwcAddLegend = $scope.renderbot.vislibVis._attr.addLegend;
+        const bwcLegendStateDefault = bwcAddLegend == null ? true : bwcAddLegend;
         $scope.open = !$scope.uiState.get('vis.legendOpen', bwcLegendStateDefault);
         $scope.uiState.set('vis.legendOpen', $scope.open);
       };
@@ -79,7 +79,7 @@ uiModules.get('kibana')
       };
 
       $scope.canFilter = function (legendData) {
-        let filters = clickHandler({point: legendData}, true) || [];
+        const filters = clickHandler({point: legendData}, true) || [];
         return filters.length;
       };
 
@@ -94,7 +94,7 @@ uiModules.get('kibana')
       ];
 
       function refresh() {
-        let vislibVis = $scope.renderbot.vislibVis;
+        const vislibVis = $scope.renderbot.vislibVis;
 
         if ($scope.uiState.get('vis.legendOpen') == null && vislibVis._attr.addLegend != null) {
           $scope.open = vislibVis._attr.addLegend;
@@ -113,7 +113,7 @@ uiModules.get('kibana')
       };
 
       function getSeriesLabels(data) {
-        let values = data.map(function (chart) {
+        const values = data.map(function (chart) {
           return chart.series;
         })
         .reduce(function (a, b) {
diff --git a/src/ui/public/watch_multi/__tests__/watch_multi.js b/src/ui/public/watch_multi/__tests__/watch_multi.js
index e87d124c93a89..9854db7b14b98 100644
--- a/src/ui/public/watch_multi/__tests__/watch_multi.js
+++ b/src/ui/public/watch_multi/__tests__/watch_multi.js
@@ -20,7 +20,7 @@ describe('$scope.$watchMulti', function () {
       expect($rootScope.$watchMulti).to.be.a('function');
       expect($scope).to.have.property('$watchMulti', $rootScope.$watchMulti);
 
-      let $isoScope = $scope.$new(true);
+      const $isoScope = $scope.$new(true);
       expect($isoScope).to.have.property('$watchMulti', $rootScope.$watchMulti);
     });
 
@@ -28,7 +28,7 @@ describe('$scope.$watchMulti', function () {
       $scope.a = 0;
       $scope.b = 0;
       let triggers = 0;
-      let unwatch = $scope.$watchMulti(['a', 'b'], function () { triggers++; });
+      const unwatch = $scope.$watchMulti(['a', 'b'], function () { triggers++; });
 
       // initial watch
       $scope.$apply();
@@ -53,7 +53,7 @@ describe('$scope.$watchMulti', function () {
 
   describe('simple scope watchers', function () {
     it('only triggers a single watch on initialization', function () {
-      let stub = sinon.stub();
+      const stub = sinon.stub();
 
       $scope.$watchMulti([
         'one',
@@ -66,7 +66,7 @@ describe('$scope.$watchMulti', function () {
     });
 
     it('only triggers a single watch when multiple values change', function () {
-      let stub = sinon.spy(function (a, b) {});
+      const stub = sinon.spy(function (a, b) {});
 
       $scope.$watchMulti([
         'one',
@@ -87,7 +87,7 @@ describe('$scope.$watchMulti', function () {
 
     it('passes an array of the current and previous values, in order',
     function () {
-      let stub = sinon.spy(function (a, b) {});
+      const stub = sinon.spy(function (a, b) {});
 
       $scope.one = 'a';
       $scope.two = 'b';
@@ -124,7 +124,7 @@ describe('$scope.$watchMulti', function () {
         count++;
       });
 
-      let $child = $scope.$new();
+      const $child = $scope.$new();
       $child.$watch('vals[0]', function (cur) {
         $child.vals[1] = cur;
       });
@@ -140,11 +140,11 @@ describe('$scope.$watchMulti', function () {
     let secondValue;
 
     beforeEach(function () {
-      let firstGetter = function () {
+      const firstGetter = function () {
         return firstValue;
       };
 
-      let secondGetter = function () {
+      const secondGetter = function () {
         return secondValue;
       };
 
@@ -158,7 +158,7 @@ describe('$scope.$watchMulti', function () {
     });
 
     it('should trigger the watcher on initialization', function () {
-      let stub = sinon.stub();
+      const stub = sinon.stub();
       firstValue = 'first';
       secondValue = 'second';
 
@@ -174,7 +174,7 @@ describe('$scope.$watchMulti', function () {
 
   describe('nested watchers', function () {
     it('should trigger the handler at least once', function () {
-      let $scope = $rootScope.$new();
+      const $scope = $rootScope.$new();
       $scope.$$watchers = [{
         get: _.noop,
         fn: _.noop,
@@ -187,8 +187,8 @@ describe('$scope.$watchMulti', function () {
         last: false
       }];
 
-      let first = sinon.stub();
-      let second = sinon.stub();
+      const first = sinon.stub();
+      const second = sinon.stub();
 
       function registerWatchers() {
         $scope.$watchMulti([first, second], function () {
diff --git a/src/ui/public/watch_multi/watch_multi.js b/src/ui/public/watch_multi/watch_multi.js
index 279076eea4e8b..9b855a69ee15b 100644
--- a/src/ui/public/watch_multi/watch_multi.js
+++ b/src/ui/public/watch_multi/watch_multi.js
@@ -37,15 +37,15 @@ uiModules.get('kibana')
       if (!_.isArray(expressions)) throw new TypeError('expected an array of expressions to watch');
       if (!_.isFunction(fn)) throw new TypeError('expected a function that is triggered on each watch');
 
-      let $scope = this;
-      let vals = new Array(expressions.length);
-      let prev = new Array(expressions.length);
+      const $scope = this;
+      const vals = new Array(expressions.length);
+      const prev = new Array(expressions.length);
       let fire = false;
       let init = 0;
-      let neededInits = expressions.length;
+      const neededInits = expressions.length;
 
       // first, register all of the multi-watchers
-      let unwatchers = expressions.map(function (expr, i) {
+      const unwatchers = expressions.map(function (expr, i) {
         expr = normalizeExpression($scope, expr);
         if (!expr) return;
 
@@ -85,7 +85,7 @@ uiModules.get('kibana')
 
     function normalizeExpression($scope, expr) {
       if (!expr) return;
-      let norm = {
+      const norm = {
         fn: $scope.$watch,
         deep: false
       };
diff --git a/src/ui/ui_bundle_collection.js b/src/ui/ui_bundle_collection.js
index a6b87779486b8..42556fd6478c0 100644
--- a/src/ui/ui_bundle_collection.js
+++ b/src/ui/ui_bundle_collection.js
@@ -62,7 +62,7 @@ class UiBundleCollection {
   async writeEntryFiles() {
     await this.ensureDir();
 
-    for (let bundle of this.each) {
+    for (const bundle of this.each) {
       const existing = await bundle.readEntryFile();
       const expected = bundle.renderContent();
 
@@ -76,7 +76,7 @@ class UiBundleCollection {
   async getInvalidBundles() {
     const invalids = new UiBundleCollection(this.env);
 
-    for (let bundle of this.each) {
+    for (const bundle of this.each) {
       const exists = await bundle.checkForExistingOutput();
       if (!exists) {
         invalids.add(bundle);
diff --git a/src/ui/ui_bundler_env.js b/src/ui/ui_bundler_env.js
index 9b2c52c55d446..e786f03cabc45 100644
--- a/src/ui/ui_bundler_env.js
+++ b/src/ui/ui_bundler_env.js
@@ -72,22 +72,22 @@ module.exports = class UiBundlerEnv {
     switch (type) {
       case 'loaders':
         return (plugin, spec) => {
-          for (let loader of arr(spec)) this.addLoader(loader);
+          for (const loader of arr(spec)) this.addLoader(loader);
         };
 
       case 'postLoaders':
         return (plugin, spec) => {
-          for (let loader of arr(spec)) this.addPostLoader(loader);
+          for (const loader of arr(spec)) this.addPostLoader(loader);
         };
 
       case 'noParse':
         return (plugin, spec) => {
-          for (let re of arr(spec)) this.addNoParse(re);
+          for (const re of arr(spec)) this.addNoParse(re);
         };
 
       case 'modules':
         return (plugin, spec) => {
-          for (let id of keys(spec)) this.addModule(id, spec[id], plugin.id);
+          for (const id of keys(spec)) this.addModule(id, spec[id], plugin.id);
         };
     }
   }
diff --git a/src/ui/ui_exports.js b/src/ui/ui_exports.js
index 9cd4d2dc1ebed..c3c2a5bcb20b3 100644
--- a/src/ui/ui_exports.js
+++ b/src/ui/ui_exports.js
@@ -27,7 +27,7 @@ class UiExports {
       throw new Error('unknown export types ' + unkown.join(', ') + ' in plugin ' + plugin.id);
     }
 
-    for (let consumer of this.consumers) {
+    for (const consumer of this.consumers) {
       consumer.consumePlugin && consumer.consumePlugin(plugin);
     }
 
@@ -41,7 +41,7 @@ class UiExports {
   }
 
   exportConsumer(type) {
-    for (let consumer of this.consumers) {
+    for (const consumer of this.consumers) {
       if (!consumer.exportConsumer) continue;
       const fn = consumer.exportConsumer(type);
       if (fn) return fn;
@@ -52,7 +52,7 @@ class UiExports {
       case 'apps':
         return (plugin, specs) => {
           const id = plugin.id;
-          for (let spec of [].concat(specs || [])) {
+          for (const spec of [].concat(specs || [])) {
 
             const app = this.apps.new(_.defaults({}, spec, {
               id: plugin.id,
@@ -126,7 +126,7 @@ class UiExports {
   }
 
   getAllApps() {
-    let { apps } = this;
+    const { apps } = this;
     return [...apps].concat(...apps.hidden);
   }
 
diff --git a/src/utils/collection.js b/src/utils/collection.js
index 7a18c2913ee71..89ceae1409f69 100644
--- a/src/utils/collection.js
+++ b/src/utils/collection.js
@@ -1,5 +1,5 @@
 
-let set = Symbol('internal set');
+const set = Symbol('internal set');
 
 module.exports = class Collection {
   constructor() { // Set's have a length of 0, mimic that
diff --git a/src/utils/package_json.js b/src/utils/package_json.js
index 36a953d4c000b..640db57157b8d 100644
--- a/src/utils/package_json.js
+++ b/src/utils/package_json.js
@@ -5,7 +5,7 @@ let packageDir;
 let packagePath;
 
 while (!packagePath || !existsSync(packagePath)) {
-  let prev = packageDir;
+  const prev = packageDir;
   packageDir = prev ? join(prev, '..') : __dirname;
   packagePath = join(packageDir, 'package.json');
 
diff --git a/tasks/build/babel_options.js b/tasks/build/babel_options.js
index 9c8db68e28310..4ce128014fb9c 100644
--- a/tasks/build/babel_options.js
+++ b/tasks/build/babel_options.js
@@ -1,9 +1,9 @@
 module.exports = function (grunt) {
 
-  let srcFile = 'build/kibana/src/optimize/babel_options.js';
-  let buildFile = 'build/kibana/src/optimize/babel_options.build.js';
-  let rename = require('fs').renameSync;
-  let unlink = require('fs').unlinkSync;
+  const srcFile = 'build/kibana/src/optimize/babel_options.js';
+  const buildFile = 'build/kibana/src/optimize/babel_options.build.js';
+  const rename = require('fs').renameSync;
+  const unlink = require('fs').unlinkSync;
 
   grunt.registerTask('_build:babelOptions', function () {
     unlink(srcFile);
diff --git a/tasks/build/download_node_builds.js b/tasks/build/download_node_builds.js
index e74e2e8db3551..5d649dbeac970 100644
--- a/tasks/build/download_node_builds.js
+++ b/tasks/build/download_node_builds.js
@@ -1,27 +1,27 @@
 module.exports = function (grunt) {
-  let { map, fromNode } = require('bluebird');
-  let { resolve } = require('path');
-  let { pluck } = require('lodash');
-  let { createWriteStream } = require('fs');
-  let { createGunzip } = require('zlib');
-  let { Extract } = require('tar');
-  let { rename } = require('fs');
-  let wreck = require('wreck');
+  const { map, fromNode } = require('bluebird');
+  const { resolve } = require('path');
+  const { pluck } = require('lodash');
+  const { createWriteStream } = require('fs');
+  const { createGunzip } = require('zlib');
+  const { Extract } = require('tar');
+  const { rename } = require('fs');
+  const wreck = require('wreck');
 
-  let platforms = grunt.config.get('platforms');
-  let activeDownloads = [];
+  const platforms = grunt.config.get('platforms');
+  const activeDownloads = [];
 
-  let start = async (platform) => {
-    let finalDir = platform.nodeDir;
-    let downloadDir = `${finalDir}.temp`;
+  const start = async (platform) => {
+    const finalDir = platform.nodeDir;
+    const downloadDir = `${finalDir}.temp`;
 
     if (grunt.file.isDir(platform.nodeDir)) {
       grunt.log.ok(`${platform.name} exists`);
       return;
     }
 
-    let resp = await fromNode(cb => {
-      let req = wreck.request('GET', platform.nodeUrl, null, function (err, resp) {
+    const resp = await fromNode(cb => {
+      const req = wreck.request('GET', platform.nodeUrl, null, function (err, resp) {
         if (err) {
           return cb(err);
         }
@@ -65,8 +65,8 @@ module.exports = function (grunt) {
 
     activeDownloads.push(platform);
 
-    let bytes = parseInt(resp.headers['content-length'], 10) || 'unknown number of';
-    let mb = ((bytes / 1024) / 1024).toFixed(2);
+    const bytes = parseInt(resp.headers['content-length'], 10) || 'unknown number of';
+    const mb = ((bytes / 1024) / 1024).toFixed(2);
     grunt.log.ok(`downloading ${platform.name} - ${mb} mb`);
   };
 
diff --git a/tasks/build/index.js b/tasks/build/index.js
index 4de6a1407a364..2127c18e25a6d 100644
--- a/tasks/build/index.js
+++ b/tasks/build/index.js
@@ -1,5 +1,5 @@
 module.exports = function (grunt) {
-  let { flatten } = require('lodash');
+  const { flatten } = require('lodash');
 
   grunt.registerTask('build', 'Build packages', function () {
     grunt.task.run(flatten([
diff --git a/tasks/build/install_npm_deps.js b/tasks/build/install_npm_deps.js
index efebb5e5ac34b..7ef36c6ee6582 100644
--- a/tasks/build/install_npm_deps.js
+++ b/tasks/build/install_npm_deps.js
@@ -1,6 +1,6 @@
 module.exports = function (grunt) {
-  let { exec } = require('child_process');
-  let { resolve } = require('path');
+  const { exec } = require('child_process');
+  const { resolve } = require('path');
 
   grunt.registerTask('_build:installNpmDeps', function () {
     grunt.file.mkdir('build/kibana/node_modules');
diff --git a/tasks/build/package_json.js b/tasks/build/package_json.js
index a9038a2dd6d5b..433e7b8d157b9 100644
--- a/tasks/build/package_json.js
+++ b/tasks/build/package_json.js
@@ -1,8 +1,8 @@
 module.exports = function (grunt) {
-  let { defaults } = require('lodash');
+  const { defaults } = require('lodash');
 
-  let pkg = grunt.config.get('pkg');
-  let deepModules = grunt.config.get('deepModules');
+  const pkg = grunt.config.get('pkg');
+  const deepModules = grunt.config.get('deepModules');
 
   grunt.registerTask('_build:packageJson', function () {
     const { sha, number, version } = grunt.config.get('build');
diff --git a/tasks/build/readme.js b/tasks/build/readme.js
index aa139c1df400f..25e799abe5588 100644
--- a/tasks/build/readme.js
+++ b/tasks/build/readme.js
@@ -1,8 +1,8 @@
-let marked = require('marked');
-let Promise = require('bluebird');
-let { join } = require('path');
-let _ = require('lodash');
-let fs = require('fs');
+const marked = require('marked');
+const Promise = require('bluebird');
+const { join } = require('path');
+const _ = require('lodash');
+const fs = require('fs');
 
 module.exports = function (grunt) {
   grunt.registerTask('_build:readme', function () {
diff --git a/tasks/build/shasums.js b/tasks/build/shasums.js
index f6bc6a6ba8100..92495ef93e8b5 100644
--- a/tasks/build/shasums.js
+++ b/tasks/build/shasums.js
@@ -1,12 +1,12 @@
-let { promisify } = require('bluebird');
-let readdir = promisify(require('fs').readdir);
-let exec = promisify(require('child_process').exec);
-let platform = require('os').platform();
-let cmd = /^win/.test(platform) ? 'sha1sum ' : 'shasum ';
+const { promisify } = require('bluebird');
+const readdir = promisify(require('fs').readdir);
+const exec = promisify(require('child_process').exec);
+const platform = require('os').platform();
+const cmd = /^win/.test(platform) ? 'sha1sum ' : 'shasum ';
 
 module.exports = function (grunt) {
   grunt.registerTask('_build:shasums', function () {
-    let targetDir = grunt.config.get('target');
+    const targetDir = grunt.config.get('target');
 
     // for when shasums is run but archives and ospackages was not
     grunt.file.mkdir(targetDir);
diff --git a/tasks/build/versioned_links.js b/tasks/build/versioned_links.js
index 876c977fe2132..fbc6df1e6ea93 100644
--- a/tasks/build/versioned_links.js
+++ b/tasks/build/versioned_links.js
@@ -1,18 +1,18 @@
 module.exports = function (grunt) {
-  let { basename, resolve } = require('path');
-  let { forOwn } = require('lodash');
+  const { basename, resolve } = require('path');
+  const { forOwn } = require('lodash');
 
-  let exec = require('../utils/exec').silent;
+  const exec = require('../utils/exec').silent;
 
   grunt.registerTask('_build:versionedLinks', function () {
-    let rootPath = grunt.config.get('root');
+    const rootPath = grunt.config.get('root');
 
-    let buildFiles = grunt.file.expand('build/kibana/{*,.*}')
+    const buildFiles = grunt.file.expand('build/kibana/{*,.*}')
     .map(function (file) {
       return resolve(rootPath, file);
     });
 
-    let transferFiles = (source, link) => exec('cp', ['-r', source, link]);
+    const transferFiles = (source, link) => exec('cp', ['-r', source, link]);
 
     grunt.config.get('platforms').forEach(function (platform) {
       grunt.file.mkdir(platform.buildDir);
diff --git a/tasks/config/babel.js b/tasks/config/babel.js
index 5eac966fcf6c3..8bf33d79619a3 100644
--- a/tasks/config/babel.js
+++ b/tasks/config/babel.js
@@ -1,5 +1,5 @@
-let { defaults } = require('lodash');
-let babelOptions = require('../../src/optimize/babel_options');
+const { defaults } = require('lodash');
+const babelOptions = require('../../src/optimize/babel_options');
 
 module.exports = {
   build: {
diff --git a/tasks/config/clean.js b/tasks/config/clean.js
index 4128505fd189e..9bf1f410d66c5 100644
--- a/tasks/config/clean.js
+++ b/tasks/config/clean.js
@@ -1,5 +1,5 @@
 module.exports = function (grunt) {
-  let modules = Object.keys(grunt.config.get('deepModules'));
+  const modules = Object.keys(grunt.config.get('deepModules'));
   return {
     build: 'build',
     target: 'target',
diff --git a/tasks/config/eslint.js b/tasks/config/eslint.js
index 7314928335a45..cec935ffdee0c 100644
--- a/tasks/config/eslint.js
+++ b/tasks/config/eslint.js
@@ -1,4 +1,4 @@
-let resolve = require('path').resolve;
+const resolve = require('path').resolve;
 
 module.exports = function (grunt) {
   return {
diff --git a/tasks/config/esvm.js b/tasks/config/esvm.js
index 52600ae78c941..ea4460c7b62fc 100644
--- a/tasks/config/esvm.js
+++ b/tasks/config/esvm.js
@@ -1,8 +1,8 @@
 module.exports = function (grunt) {
-  let resolve = require('path').resolve;
-  let directory = resolve(__dirname, '../../esvm');
-  let dataDir = resolve(directory, 'data_dir');
-  let serverConfig = require('../../test/server_config');
+  const resolve = require('path').resolve;
+  const directory = resolve(__dirname, '../../esvm');
+  const dataDir = resolve(directory, 'data_dir');
+  const serverConfig = require('../../test/server_config');
 
   return {
     options: {
diff --git a/tasks/config/intern.js b/tasks/config/intern.js
index 8fc678855251e..2336cf918ef51 100644
--- a/tasks/config/intern.js
+++ b/tasks/config/intern.js
@@ -1,4 +1,4 @@
-let path = require('path');
+const path = require('path');
 
 
 module.exports = function (grunt) {
diff --git a/tasks/config/platforms.js b/tasks/config/platforms.js
index 5fa47841bc9bd..870de25927f94 100644
--- a/tasks/config/platforms.js
+++ b/tasks/config/platforms.js
@@ -1,12 +1,12 @@
 import { endsWith } from 'lodash';
 
 module.exports = function (grunt) {
-  let { resolve } = require('path');
+  const { resolve } = require('path');
 
-  let { version } = grunt.config.get('build');
-  let nodeVersion = grunt.config.get('nodeVersion');
-  let rootPath = grunt.config.get('root');
-  let baseUri = `https://nodejs.org/dist/v${nodeVersion}`;
+  const { version } = grunt.config.get('build');
+  const nodeVersion = grunt.config.get('nodeVersion');
+  const rootPath = grunt.config.get('root');
+  const baseUri = `https://nodejs.org/dist/v${nodeVersion}`;
 
   return [
     'darwin-x64',
@@ -14,23 +14,23 @@ module.exports = function (grunt) {
     'linux-x86',
     'windows-x86'
   ].map(function (baseName) {
-    let win = baseName === 'windows-x86';
+    const win = baseName === 'windows-x86';
 
-    let nodeUrl = win ? `${baseUri}/win-x86/node.exe` : `${baseUri}/node-v${nodeVersion}-${baseName}.tar.gz`;
-    let nodeDir = resolve(rootPath, `.node_binaries/${nodeVersion}/${baseName}`);
+    const nodeUrl = win ? `${baseUri}/win-x86/node.exe` : `${baseUri}/node-v${nodeVersion}-${baseName}.tar.gz`;
+    const nodeDir = resolve(rootPath, `.node_binaries/${nodeVersion}/${baseName}`);
 
     const name = endsWith(baseName, '-x64')
       ? baseName.replace('-x64', '-x86_64')
       : baseName;
 
-    let buildName = `kibana-${version}-${name}`;
-    let buildDir = resolve(rootPath, `build/${buildName}`);
+    const buildName = `kibana-${version}-${name}`;
+    const buildDir = resolve(rootPath, `build/${buildName}`);
 
-    let tarName = `${buildName}.tar.gz`;
-    let tarPath = resolve(rootPath, `target/${tarName}`);
+    const tarName = `${buildName}.tar.gz`;
+    const tarPath = resolve(rootPath, `target/${tarName}`);
 
-    let zipName = `${buildName}.zip`;
-    let zipPath = resolve(rootPath, `target/${zipName}`);
+    const zipName = `${buildName}.zip`;
+    const zipPath = resolve(rootPath, `target/${zipName}`);
 
     let debName;
     let debPath;
diff --git a/tasks/config/run.js b/tasks/config/run.js
index 780f2362f2821..242a97506d2ce 100644
--- a/tasks/config/run.js
+++ b/tasks/config/run.js
@@ -1,12 +1,12 @@
 module.exports = function (grunt) {
-  let platform = require('os').platform();
-  let {format} = require('url');
-  let {resolve} = require('path');
-  let root = p => resolve(__dirname, '../../', p);
-  let binScript =  /^win/.test(platform) ? '.\\bin\\kibana.bat' : './bin/kibana';
-  let buildScript =  /^win/.test(platform) ? '.\\build\\kibana\\bin\\kibana.bat' : './build/kibana/bin/kibana';
-  let uiConfig = require(root('test/server_config'));
-  let chromedriver = require('chromedriver');
+  const platform = require('os').platform();
+  const {format} = require('url');
+  const {resolve} = require('path');
+  const root = p => resolve(__dirname, '../../', p);
+  const binScript =  /^win/.test(platform) ? '.\\bin\\kibana.bat' : './bin/kibana';
+  const buildScript =  /^win/.test(platform) ? '.\\build\\kibana\\bin\\kibana.bat' : './build/kibana/bin/kibana';
+  const uiConfig = require(root('test/server_config'));
+  const chromedriver = require('chromedriver');
 
   const stdDevArgs = [
     '--env.name=development',
diff --git a/tasks/config/s3.js b/tasks/config/s3.js
index c9c1ff0e1a68b..6a84ee445bfc9 100644
--- a/tasks/config/s3.js
+++ b/tasks/config/s3.js
@@ -1,5 +1,5 @@
 module.exports = function (grunt) {
-  let { config } = grunt;
+  const { config } = grunt;
 
   return {
     release: {
diff --git a/tasks/config/services.js b/tasks/config/services.js
index 8b74b36c0319e..18a07da7be0f3 100644
--- a/tasks/config/services.js
+++ b/tasks/config/services.js
@@ -1,6 +1,6 @@
 module.exports = function (grunt) {
-  let { resolve } = require('path');
-  let rootDir = grunt.config.get('root');
+  const { resolve } = require('path');
+  const rootDir = grunt.config.get('root');
 
   return [
     ['launchd', '10.9'],
diff --git a/tasks/licenses.js b/tasks/licenses.js
index b105a90839995..fe5551c780338 100644
--- a/tasks/licenses.js
+++ b/tasks/licenses.js
@@ -46,7 +46,7 @@ export default function licenses(grunt) {
      */
 
     function isInvalidLicense(name) {
-      let licenses = licensesForPackage(name);
+      const licenses = licensesForPackage(name);
 
       // verify all licenses for the package are in the config
       return _.intersection(licenses, config.licenses).length < licenses.length;
diff --git a/tasks/lint_staged_files.js b/tasks/lint_staged_files.js
index 07d13efca4889..f04f7d8945b20 100644
--- a/tasks/lint_staged_files.js
+++ b/tasks/lint_staged_files.js
@@ -8,7 +8,7 @@ export default function (grunt) {
     grunt.task.requires('collectFilesToCommit');
 
     // match these patterns
-    let patterns = grunt.config.get('eslint.source.files.src');
+    const patterns = grunt.config.get('eslint.source.files.src');
     if (!patterns) grunt.fail.warn('eslint file pattern is not defined');
 
     const files = grunt.config
diff --git a/tasks/release.js b/tasks/release.js
index 90601b8993e03..ab72d50379d2d 100644
--- a/tasks/release.js
+++ b/tasks/release.js
@@ -50,7 +50,7 @@ module.exports = function (grunt) {
 
     fs.readdirSync('./target').forEach((file) => {
       if (path.extname(file) !== '.txt') {
-        let link = url.format({
+        const link = url.format({
           protocol: 'https',
           hostname: 'download.elastic.co',
           pathname: config[0].dest + file
diff --git a/tasks/release_packages.js b/tasks/release_packages.js
index 87accb94fd524..d4fcd107ec417 100644
--- a/tasks/release_packages.js
+++ b/tasks/release_packages.js
@@ -59,7 +59,7 @@ export default (grunt) => {
       grunt.fail.fatal('Aborting publish');
     }
 
-    let rl = readline.createInterface({
+    const rl = readline.createInterface({
       input: process.stdin,
       output: process.stdout
     });
diff --git a/tasks/sterilize.js b/tasks/sterilize.js
index 7e194d440e9df..897987f31794f 100644
--- a/tasks/sterilize.js
+++ b/tasks/sterilize.js
@@ -26,7 +26,7 @@ export default function (grunt) {
 
     rl.on('close', this.async());
     rl.question(`\n${danger} Do you really want to delete all of the above files?, [N/y] `, function (resp) {
-      let yes = resp.toLowerCase().trim()[0] === 'y';
+      const yes = resp.toLowerCase().trim()[0] === 'y';
       rl.close();
 
       if (yes) {
diff --git a/tasks/utils/exec.js b/tasks/utils/exec.js
index ec63ada6f9afd..be614f1ce8473 100644
--- a/tasks/utils/exec.js
+++ b/tasks/utils/exec.js
@@ -1,4 +1,4 @@
-let { execFileSync } = require('child_process');
+const { execFileSync } = require('child_process');
 
 function exec(cmd, args, opts) {
   console.log(' >', cmd, args.join(' '));
diff --git a/tasks/utils/install_or_update_repo.js b/tasks/utils/install_or_update_repo.js
index f803cf33d5801..78e4e87594140 100644
--- a/tasks/utils/install_or_update_repo.js
+++ b/tasks/utils/install_or_update_repo.js
@@ -1,6 +1,6 @@
-let Promise = require('bluebird');
-let spawn = require('./spawn');
-let grunt = require('grunt');
+const Promise = require('bluebird');
+const spawn = require('./spawn');
+const grunt = require('grunt');
 
 module.exports = function (repo, dir) {
   // store the previous and new hash from the repo
diff --git a/tasks/utils/update_version.js b/tasks/utils/update_version.js
index e38436ab08cf2..4580cf6072e49 100644
--- a/tasks/utils/update_version.js
+++ b/tasks/utils/update_version.js
@@ -1,8 +1,8 @@
-let _ = require('lodash');
+const _ = require('lodash');
 
 module.exports = updateVersion;
 
-let versions = [
+const versions = [
   'major',
   'minor',
   'patch',
@@ -44,7 +44,7 @@ let versions = [
 function updateVersion(version, expr) {
   expr = String(expr).split('=');
 
-  let change = {
+  const change = {
     name: expr[0],
     val: expr[1] || null
   };
@@ -58,7 +58,7 @@ function updateVersion(version, expr) {
   }
 
   // parse the current version
-  let parts = _.chain(version.split('.'))
+  const parts = _.chain(version.split('.'))
 
   // ensure that their are three pieces, either x.x.x or x.x.x-y
   .tap(function (versionNumbers) {
@@ -70,7 +70,7 @@ function updateVersion(version, expr) {
   // describe all of the version parts with a name, parse
   // the numbers, and extract tag from patch
   .transform(function (parts, v, i) {
-    let name = versions[i];
+    const name = versions[i];
 
     if (name !== 'patch') {
       parts[name] = _.parseInt(v);
@@ -121,7 +121,7 @@ function updateVersion(version, expr) {
     }
 
     // properties that are zero-d by the previous update
-    let emptyUpdates = versions.slice(versions.indexOf(change.name) + 1);
+    const emptyUpdates = versions.slice(versions.indexOf(change.name) + 1);
     while (emptyUpdates.length) {
       parts[emptyUpdates.shift()] = '';
     }
diff --git a/test/fixtures/__tests__/scenario_manager.js b/test/fixtures/__tests__/scenario_manager.js
index fd271a388d6f8..7cf7dd8df0094 100644
--- a/test/fixtures/__tests__/scenario_manager.js
+++ b/test/fixtures/__tests__/scenario_manager.js
@@ -1,11 +1,11 @@
-let expect = require('expect.js');
-let sinon = require('sinon');
-let Promise = require('bluebird');
+const expect = require('expect.js');
+const sinon = require('sinon');
+const Promise = require('bluebird');
 
-let ScenarioManager = require('../scenario_manager');
+const ScenarioManager = require('../scenario_manager');
 
 describe('scenario manager', function () {
-  let manager = new ScenarioManager('http://localhost:9200');
+  const manager = new ScenarioManager('http://localhost:9200');
 
   describe('loading and unloading', function () {
     this.timeout(60000);
@@ -43,9 +43,9 @@ describe('scenario manager', function () {
     });
 
     it('should be able to reload a scenario', function () {
-      let load = sinon.stub(manager, 'load', Promise.resolve);
-      let unload = sinon.stub(manager, 'unload', Promise.resolve);
-      let id = 'makelogs';
+      const load = sinon.stub(manager, 'load', Promise.resolve);
+      const unload = sinon.stub(manager, 'unload', Promise.resolve);
+      const id = 'makelogs';
       return manager.reload(id).then(function () {
         expect(load.calledWith(id)).to.be(true);
         expect(unload.calledWith(id)).to.be(true);
@@ -56,9 +56,9 @@ describe('scenario manager', function () {
     });
 
     it('should load if the index does not exist', function () {
-      let load = sinon.stub(manager, 'load', Promise.resolve);
-      let throwError = sinon.stub(manager.client, 'count', Promise.reject);
-      let id = 'makelogs';
+      const load = sinon.stub(manager, 'load', Promise.resolve);
+      const throwError = sinon.stub(manager.client, 'count', Promise.reject);
+      const id = 'makelogs';
       return manager.loadIfEmpty(id).then(function () {
         expect(load.calledWith(id)).to.be(true);
 
@@ -68,13 +68,13 @@ describe('scenario manager', function () {
     });
 
     it('should load if the index is empty', function () {
-      let load = sinon.stub(manager, 'load', Promise.resolve);
-      let returnZero = sinon.stub(manager.client, 'count', function () {
+      const load = sinon.stub(manager, 'load', Promise.resolve);
+      const returnZero = sinon.stub(manager.client, 'count', function () {
         return Promise.resolve({
           'count': 0
         });
       });
-      let id = 'makelogs';
+      const id = 'makelogs';
       return manager.loadIfEmpty(id).then(function () {
         expect(load.calledWith(id)).to.be(true);
 
@@ -85,13 +85,13 @@ describe('scenario manager', function () {
 
 
     it('should not load if the index is not empty', function () {
-      let load = sinon.stub(manager, 'load', Promise.resolve);
-      let returnOne = sinon.stub(manager.client, 'count', function () {
+      const load = sinon.stub(manager, 'load', Promise.resolve);
+      const returnOne = sinon.stub(manager.client, 'count', function () {
         return Promise.resolve({
           'count': 1
         });
       });
-      let id = 'makelogs';
+      const id = 'makelogs';
       return manager.loadIfEmpty(id).then(function () {
         expect(load.called).to.be(false);
 
diff --git a/test/fixtures/config.js b/test/fixtures/config.js
index 911d6caa74dcd..0a99160472db1 100644
--- a/test/fixtures/config.js
+++ b/test/fixtures/config.js
@@ -1,5 +1,5 @@
-let path = require('path');
-let rootDir = path.join(__dirname, 'scenarios');
+const path = require('path');
+const rootDir = path.join(__dirname, 'scenarios');
 
 module.exports = {
   scenarios: {
diff --git a/test/fixtures/scenario_manager.js b/test/fixtures/scenario_manager.js
index 24965de1b2b29..28e19cf1a36c0 100644
--- a/test/fixtures/scenario_manager.js
+++ b/test/fixtures/scenario_manager.js
@@ -1,7 +1,7 @@
-let path = require('path');
-let elasticsearch = require('elasticsearch');
-let Promise = require('bluebird');
-let config = require('./config').scenarios;
+const path = require('path');
+const elasticsearch = require('elasticsearch');
+const Promise = require('bluebird');
+const config = require('./config').scenarios;
 
 function ScenarioManager(server) {
   if (!server) throw new Error('No server defined');
@@ -23,14 +23,14 @@ function ScenarioManager(server) {
 * @return {Promise} A promise that is resolved when elasticsearch has a response
 */
 ScenarioManager.prototype.load = function (id) {
-  let self = this;
-  let scenario = config[id];
+  const self = this;
+  const scenario = config[id];
   if (!scenario) return Promise.reject('No scenario found for ' + id);
 
   return Promise.all(scenario.bulk.map(function mapBulk(bulk) {
     let loadIndexDefinition;
     if (bulk.indexDefinition) {
-      let body = require(path.join(scenario.baseDir, bulk.indexDefinition));
+      const body = require(path.join(scenario.baseDir, bulk.indexDefinition));
       loadIndexDefinition = self.client.indices.create({
         index: bulk.indexName,
         body: body
@@ -41,7 +41,7 @@ ScenarioManager.prototype.load = function (id) {
 
     return loadIndexDefinition
     .then(function bulkRequest() {
-      let body = require(path.join(scenario.baseDir, bulk.source));
+      const body = require(path.join(scenario.baseDir, bulk.source));
       return self.client.bulk({
         body: body
       });
@@ -71,10 +71,10 @@ ScenarioManager.prototype.load = function (id) {
 * @return {Promise} A promise that is resolved when elasticsearch has a response
 */
 ScenarioManager.prototype.unload = function (id) {
-  let scenario = config[id];
+  const scenario = config[id];
   if (!scenario) return Promise.reject('No scenario found for ' + id);
 
-  let indices = scenario.bulk.map(function mapBulk(bulk) {
+  const indices = scenario.bulk.map(function mapBulk(bulk) {
     return bulk.indexName;
   });
 
@@ -96,7 +96,7 @@ ScenarioManager.prototype.unload = function (id) {
 * @return {Promise} A promise that is resolved when elasticsearch has a response
 */
 ScenarioManager.prototype.reload = function (id) {
-  let self = this;
+  const self = this;
 
   return self.unload(id)
   .then(function load() {
@@ -120,8 +120,8 @@ ScenarioManager.prototype.deleteAll = function () {
  * @return {Promise} A promise that is resolved when elasticsearch has a response
  */
 ScenarioManager.prototype.loadIfEmpty = function (id) {
-  let self = this;
-  let scenario = config[id];
+  const self = this;
+  const scenario = config[id];
   if (!scenario) throw new Error('No scenario found for ' + id);
 
   return Promise.all(scenario.bulk.map(function mapBulk(bulk) {
diff --git a/test/functional/apps/console/_console.js b/test/functional/apps/console/_console.js
index 69259c7cf947b..6d52c36846ced 100644
--- a/test/functional/apps/console/_console.js
+++ b/test/functional/apps/console/_console.js
@@ -15,7 +15,7 @@ bdd.describe('console app', function describeIndexTests() {
   });
 
   bdd.it('should show the default request', function () {
-    let expectedRequest = [
+    const expectedRequest = [
       'GET _search',
       '{',
       '  "query": {',
@@ -39,7 +39,7 @@ bdd.describe('console app', function describeIndexTests() {
   });
 
   bdd.it('default request response should contain .kibana' , function () {
-    let expectedResponseContains = '"_index": ".kibana",';
+    const expectedResponseContains = '"_index": ".kibana",';
     return PageObjects.console.clickPlay()
     .then(function () {
       PageObjects.common.saveScreenshot('Console-default-request');
diff --git a/test/functional/apps/dashboard/_dashboard.js b/test/functional/apps/dashboard/_dashboard.js
index 523b84dafebe6..14a199fc62269 100644
--- a/test/functional/apps/dashboard/_dashboard.js
+++ b/test/functional/apps/dashboard/_dashboard.js
@@ -13,7 +13,7 @@ import PageObjects from '../../../support/page_objects';
 bdd.describe('dashboard tab', function describeIndexTests() {
   bdd.before(function () {
     PageObjects.common.debug('Starting dashboard before method');
-    let logstash = scenarioManager.loadIfEmpty('logstashFunctional');
+    const logstash = scenarioManager.loadIfEmpty('logstashFunctional');
     // delete .kibana index and update configDoc
     return esClient.deleteAndUpdateConfigDoc({'dateFormat:tz':'UTC', 'defaultIndex':'logstash-*'})
     // and load a set of makelogs data
@@ -32,7 +32,7 @@ bdd.describe('dashboard tab', function describeIndexTests() {
   });
 
   bdd.describe('add visualizations to dashboard', function dashboardTest() {
-    let visualizations = ['Visualization漢字 AreaChart',
+    const visualizations = ['Visualization漢字 AreaChart',
       'Visualization☺漢字 DataTable',
       'Visualization漢字 LineChart',
       'Visualization PieChart',
@@ -61,8 +61,8 @@ bdd.describe('dashboard tab', function describeIndexTests() {
     });
 
     bdd.it('set the timepicker time to that which contains our test data', function setTimepicker() {
-      let fromTime = '2015-09-19 06:31:44.000';
-      let toTime = '2015-09-23 18:31:44.000';
+      const fromTime = '2015-09-19 06:31:44.000';
+      const toTime = '2015-09-23 18:31:44.000';
 
       // .then(function () {
       PageObjects.common.debug('Set absolute time range from \"' + fromTime + '\" to \"' + toTime + '\"');
@@ -111,7 +111,7 @@ bdd.describe('dashboard tab', function describeIndexTests() {
     });
 
     bdd.it('should have all the expected initial sizes', function checkVisualizationSizes() {
-      let visObjects = [ { dataCol: '1', dataRow: '1', dataSizeX: '3', dataSizeY: '2', title: 'Visualization漢字 AreaChart' },
+      const visObjects = [ { dataCol: '1', dataRow: '1', dataSizeX: '3', dataSizeY: '2', title: 'Visualization漢字 AreaChart' },
         { dataCol: '4', dataRow: '1', dataSizeX: '3', dataSizeY: '2', title: 'Visualization☺漢字 DataTable' },
         { dataCol: '7', dataRow: '1', dataSizeX: '3', dataSizeY: '2', title: 'Visualization漢字 LineChart' },
         { dataCol: '10', dataRow: '1', dataSizeX: '3', dataSizeY: '2', title: 'Visualization PieChart' },
diff --git a/test/functional/apps/discover/_collapse_expand.js b/test/functional/apps/discover/_collapse_expand.js
index 91b9f7253c2be..e5f2e3b8ef384 100644
--- a/test/functional/apps/discover/_collapse_expand.js
+++ b/test/functional/apps/discover/_collapse_expand.js
@@ -12,8 +12,8 @@ import PageObjects from '../../../support/page_objects';
 
 bdd.describe('discover tab', function describeIndexTests() {
   bdd.before(function () {
-    let fromTime = '2015-09-19 06:31:44.000';
-    let toTime = '2015-09-23 18:31:44.000';
+    const fromTime = '2015-09-19 06:31:44.000';
+    const toTime = '2015-09-23 18:31:44.000';
 
     // delete .kibana index and update configDoc
     return esClient.deleteAndUpdateConfigDoc({'dateFormat:tz':'UTC', 'defaultIndex':'logstash-*'})
diff --git a/test/functional/apps/discover/_discover.js b/test/functional/apps/discover/_discover.js
index 9e0fefa43fce6..8266d0ec4d6cf 100644
--- a/test/functional/apps/discover/_discover.js
+++ b/test/functional/apps/discover/_discover.js
@@ -12,8 +12,8 @@ import PageObjects from '../../../support/page_objects';
 
 bdd.describe('discover app', function describeIndexTests() {
   bdd.before(function () {
-    let fromTime = '2015-09-19 06:31:44.000';
-    let toTime = '2015-09-23 18:31:44.000';
+    const fromTime = '2015-09-19 06:31:44.000';
+    const toTime = '2015-09-23 18:31:44.000';
 
     // delete .kibana index and update configDoc
     return esClient.deleteAndUpdateConfigDoc({'dateFormat:tz':'UTC', 'defaultIndex':'logstash-*'})
@@ -37,12 +37,12 @@ bdd.describe('discover app', function describeIndexTests() {
 
 
   bdd.describe('query', function () {
-    let queryName1 = 'Query # 1';
-    let fromTimeString = 'September 19th 2015, 06:31:44.000';
-    let toTimeString = 'September 23rd 2015, 18:31:44.000';
+    const queryName1 = 'Query # 1';
+    const fromTimeString = 'September 19th 2015, 06:31:44.000';
+    const toTimeString = 'September 23rd 2015, 18:31:44.000';
 
     bdd.it('should show correct time range string by timepicker', function () {
-      let expectedTimeRangeString = fromTimeString + ' to ' + toTimeString;
+      const expectedTimeRangeString = fromTimeString + ' to ' + toTimeString;
       return PageObjects.discover.getTimespanText()
       .then(function (actualTimeString) {
         expect(actualTimeString).to.be(expectedTimeRangeString);
@@ -50,7 +50,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('save query should show toast message and display query name', function () {
-      let expectedSavedQueryMessage = 'Discover: Saved Data Source "' + queryName1 + '"';
+      const expectedSavedQueryMessage = 'Discover: Saved Data Source "' + queryName1 + '"';
       return PageObjects.discover.saveSearch(queryName1)
       .then(function () {
         return PageObjects.header.getToastMessage();
@@ -85,7 +85,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show the correct hit count', function () {
-      let expectedHitCount = '14,004';
+      const expectedHitCount = '14,004';
       return PageObjects.common.try(function tryingForTime() {
         return PageObjects.discover.getHitCount()
         .then(function compareData(hitCount) {
@@ -95,7 +95,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show the correct bar chart', function () {
-      let expectedBarChartData = [ '3.237',
+      const expectedBarChartData = [ '3.237',
         '17.674', '64.75', '125.737', '119.962', '65.712', '16.449',
         '2.712', '3.675', '17.674', '59.762', '119.087', '123.812',
         '61.862', '15.487', '2.362', '2.800', '15.312', '61.862', '123.2',
@@ -108,7 +108,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct time range string in chart', function () {
-      let expectedTimeRangeString = fromTimeString + ' - ' + toTimeString;
+      const expectedTimeRangeString = fromTimeString + ' - ' + toTimeString;
       return PageObjects.discover.getChartTimespan()
       .then(function (actualTimeString) {
         expect(actualTimeString).to.be(expectedTimeRangeString);
@@ -116,7 +116,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct initial chart interval of 3 hours', function () {
-      let expectedChartInterval = 'by 3 hours';
+      const expectedChartInterval = 'by 3 hours';
       return PageObjects.discover.getChartInterval()
       .then(function (actualInterval) {
         expect(actualInterval).to.be(expectedChartInterval);
@@ -124,8 +124,8 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data for chart interval Hourly', function () {
-      let chartInterval = 'Hourly';
-      let expectedBarChartData = [ '1.527', '2.290',
+      const chartInterval = 'Hourly';
+      const expectedBarChartData = [ '1.527', '2.290',
         '5.599', '7.890', '13.236', '30.290', '46.072', '55.490', '86.8',
         '112', '122.181', '131.6', '132.872', '113.527', '102.581',
         '81.709', '65.672', '43.781', '24.181', '14', '9.672', '6.109',
@@ -148,8 +148,8 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data for chart interval Daily', function () {
-      let chartInterval = 'Daily';
-      let expectedBarChartData = [
+      const chartInterval = 'Daily';
+      const expectedBarChartData = [
         '133.196', '129.192', '129.724'
       ];
       return PageObjects.discover.setChartInterval(chartInterval)
@@ -162,8 +162,8 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data for chart interval Weekly', function () {
-      let chartInterval = 'Weekly';
-      let expectedBarChartData = [ '66.598', '129.458'];
+      const chartInterval = 'Weekly';
+      const expectedBarChartData = [ '66.598', '129.458'];
       return PageObjects.discover.setChartInterval(chartInterval)
       .then(function () {
         return PageObjects.common.sleep(2000);
@@ -174,8 +174,8 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('browser back button should show previous interval Daily', function () {
-      let expectedChartInterval = 'Daily';
-      let expectedBarChartData = [
+      const expectedChartInterval = 'Daily';
+      const expectedBarChartData = [
         '133.196', '129.192', '129.724'
       ];
       return this.remote.goBack()
@@ -193,8 +193,8 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data for chart interval Monthly', function () {
-      let chartInterval = 'Monthly';
-      let expectedBarChartData = [ '122.535'];
+      const chartInterval = 'Monthly';
+      const expectedBarChartData = [ '122.535'];
       return PageObjects.discover.setChartInterval(chartInterval)
       .then(function () {
         return PageObjects.common.sleep(2000);
@@ -205,8 +205,8 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data for chart interval Yearly', function () {
-      let chartInterval = 'Yearly';
-      let expectedBarChartData = [ '122.535'];
+      const chartInterval = 'Yearly';
+      const expectedBarChartData = [ '122.535'];
       return PageObjects.discover.setChartInterval(chartInterval)
       .then(function () {
         return PageObjects.common.sleep(2000);
@@ -217,8 +217,8 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data for chart interval Auto', function () {
-      let chartInterval = 'Auto';
-      let expectedBarChartData = [ '3.237',
+      const chartInterval = 'Auto';
+      const expectedBarChartData = [ '3.237',
         '17.674', '64.75', '125.737', '119.962', '65.712', '16.449',
         '2.712', '3.675', '17.674', '59.762', '119.087', '123.812',
         '61.862', '15.487', '2.362', '2.800', '15.312', '61.862', '123.2',
@@ -234,7 +234,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('should show Auto chart interval of 3 hours', function () {
-      let expectedChartInterval = 'by 3 hours';
+      const expectedChartInterval = 'by 3 hours';
       return PageObjects.discover.getChartInterval()
       .then(function (actualInterval) {
         expect(actualInterval).to.be(expectedChartInterval);
@@ -252,7 +252,7 @@ bdd.describe('discover app', function describeIndexTests() {
         return PageObjects.discover.getBarChartData()
         .then(function compareData(paths) {
           // the largest bars are over 100 pixels high so this is less than 1% tolerance
-          let barHeightTolerance = 1;
+          const barHeightTolerance = 1;
           let stringResults = '';
           let hasFailure = false;
           for (let y = 0; y < expectedBarChartData.length; y++) {
@@ -277,8 +277,8 @@ bdd.describe('discover app', function describeIndexTests() {
   });
 
   bdd.describe('query #2, which has an empty time range', function () {
-    let fromTime = '1999-06-11 09:22:11.000';
-    let toTime = '1999-06-12 11:21:04.000';
+    const fromTime = '1999-06-11 09:22:11.000';
+    const toTime = '1999-06-12 11:21:04.000';
 
     bdd.before(() => {
       PageObjects.common.debug('setAbsoluteRangeForAnotherQuery');
diff --git a/test/functional/apps/discover/_field_data.js b/test/functional/apps/discover/_field_data.js
index 35a33bdd331b3..12fbbdaaa8658 100644
--- a/test/functional/apps/discover/_field_data.js
+++ b/test/functional/apps/discover/_field_data.js
@@ -12,8 +12,8 @@ import PageObjects from '../../../support/page_objects';
 
 bdd.describe('discover app', function describeIndexTests() {
   bdd.before(function () {
-    let fromTime = '2015-09-19 06:31:44.000';
-    let toTime = '2015-09-23 18:31:44.000';
+    const fromTime = '2015-09-19 06:31:44.000';
+    const toTime = '2015-09-23 18:31:44.000';
 
     // delete .kibana index and update configDoc
     return esClient.deleteAndUpdateConfigDoc({'dateFormat:tz':'UTC', 'defaultIndex':'logstash-*'})
@@ -37,12 +37,12 @@ bdd.describe('discover app', function describeIndexTests() {
 
 
   bdd.describe('field data', function () {
-    let queryName1 = 'Query # 1';
-    let fromTimeString = 'September 19th 2015, 06:31:44.000';
-    let toTimeString = 'September 23rd 2015, 18:31:44.000';
+    const queryName1 = 'Query # 1';
+    const fromTimeString = 'September 19th 2015, 06:31:44.000';
+    const toTimeString = 'September 23rd 2015, 18:31:44.000';
 
     bdd.it('search php should show the correct hit count', function () {
-      let expectedHitCount = '445';
+      const expectedHitCount = '445';
       return PageObjects.discover.query('php')
       .then(function () {
         return PageObjects.common.try(function tryingForTime() {
@@ -65,7 +65,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('search _type:apache should show the correct hit count', function () {
-      let expectedHitCount = '11,156';
+      const expectedHitCount = '11,156';
       return PageObjects.discover.query('_type:apache')
       .then(function () {
         return PageObjects.common.try(function tryingForTime() {
@@ -78,7 +78,7 @@ bdd.describe('discover app', function describeIndexTests() {
     });
 
     bdd.it('doc view should show Time and _source columns', function () {
-      let expectedHeader = 'Time _source';
+      const expectedHeader = 'Time _source';
       return PageObjects.discover.getDocHeader()
       .then(function (header) {
         expect(header).to.be(expectedHeader);
@@ -87,7 +87,7 @@ bdd.describe('discover app', function describeIndexTests() {
 
     bdd.it('doc view should show oldest time first', function () {
       // Note: Could just check the timestamp, but might as well check that the whole doc is as expected.
-      let ExpectedDoc =
+      const ExpectedDoc =
         'September 22nd 2015, 23:50:13.253 index:logstash-2015.09.22 @timestamp:September 22nd 2015, 23:50:13.253'
         + ' ip:238.171.34.42 extension:jpg response:200 geo.coordinates:{ "lat": 38.66494528, "lon": -88.45299556'
         + ' } geo.src:FR geo.dest:KH geo.srcdest:FR:KH @tags:success, info utc_time:September 22nd 2015,'
@@ -138,7 +138,7 @@ bdd.describe('discover app', function describeIndexTests() {
 
     bdd.it('doc view should sort ascending', function () {
       // Note: Could just check the timestamp, but might as well check that the whole doc is as expected.
-      let ExpectedDoc =
+      const ExpectedDoc =
         'September 20th 2015, 00:00:00.000 index:logstash-2015.09.20 @timestamp:September 20th 2015, 00:00:00.000'
         + ' ip:143.84.142.7 extension:jpg response:200 geo.coordinates:{ "lat": 38.68407028, "lon": -120.9871642 }'
         + ' geo.src:ES geo.dest:US geo.srcdest:ES:US @tags:error, info utc_time:September 20th 2015, 00:00:00.000'
@@ -230,8 +230,8 @@ bdd.describe('discover app', function describeIndexTests() {
 
 
     bdd.it('a bad syntax query should show an error message', function () {
-      let expectedHitCount = '1011,156';
-      let expectedError = 'Discover: Failed to parse query [xxx(yyy]';
+      const expectedHitCount = '1011,156';
+      const expectedError = 'Discover: Failed to parse query [xxx(yyy]';
       return PageObjects.discover.query('xxx(yyy')
       .then(function () {
         return PageObjects.header.getToastMessage();
diff --git a/test/functional/apps/discover/_shared_links.js b/test/functional/apps/discover/_shared_links.js
index 1f54f5b722058..ba1cd25b3dc7c 100644
--- a/test/functional/apps/discover/_shared_links.js
+++ b/test/functional/apps/discover/_shared_links.js
@@ -16,13 +16,13 @@ bdd.describe('shared links', function describeIndexTests() {
   // var expectedToastMessage = 'Share search: URL selected. Press Ctrl+C to copy.';
   // var expectedToastMessage = 'Share search: URL copied to clipboard.';
   // Pass either one.
-  let expectedToastMessage = /Share search: URL (selected\. Press Ctrl\+C to copy\.|copied to clipboard\.)/;
+  const expectedToastMessage = /Share search: URL (selected\. Press Ctrl\+C to copy\.|copied to clipboard\.)/;
 
   bdd.before(function () {
     baseUrl = PageObjects.common.getHostPort();
 
-    let fromTime = '2015-09-19 06:31:44.000';
-    let toTime = '2015-09-23 18:31:44.000';
+    const fromTime = '2015-09-19 06:31:44.000';
+    const toTime = '2015-09-23 18:31:44.000';
 
     // delete .kibana index and update configDoc
     return esClient.deleteAndUpdateConfigDoc({'dateFormat:tz':'UTC', 'defaultIndex':'logstash-*'})
@@ -52,7 +52,7 @@ bdd.describe('shared links', function describeIndexTests() {
 
   bdd.describe('shared link', function () {
     bdd.it('should show "Share a link" caption', function () {
-      let expectedCaption = 'Share a link';
+      const expectedCaption = 'Share a link';
       return PageObjects.discover.clickShare()
       .then(function () {
         PageObjects.common.saveScreenshot('Discover-share-link');
@@ -64,7 +64,7 @@ bdd.describe('shared links', function describeIndexTests() {
     });
 
     bdd.it('should show the correct formatted URL', function () {
-      let expectedUrl = baseUrl
+      const expectedUrl = baseUrl
         + '/app/kibana?_t=1453775307251#'
         + '/discover?_g=(refreshInterval:(display:Off,pause:!f,value:0),time'
         + ':(from:\'2015-09-19T06:31:44.000Z\',mode:absolute,to:\'2015-09'
@@ -95,7 +95,7 @@ bdd.describe('shared links', function describeIndexTests() {
 
     // TODO: verify clipboard contents
     bdd.it('shorten URL button should produce a short URL', function () {
-      let re = new RegExp(baseUrl + '/goto/[0-9a-f]{32}$');
+      const re = new RegExp(baseUrl + '/goto/[0-9a-f]{32}$');
       return PageObjects.discover.clickShortenUrl()
       .then(function () {
         return PageObjects.common.try(function tryingForTime() {
diff --git a/test/functional/apps/management/_creation_form_changes.js b/test/functional/apps/management/_creation_form_changes.js
index 6920447acf111..1e0e26fd854b5 100644
--- a/test/functional/apps/management/_creation_form_changes.js
+++ b/test/functional/apps/management/_creation_form_changes.js
@@ -22,7 +22,7 @@ bdd.describe('user input reactions', function () {
   });
 
   bdd.it('should hide time-based index pattern when time-based option is unchecked', function () {
-    let self = this;
+    const self = this;
     return PageObjects.settings.getTimeBasedEventsCheckbox()
     .then(function (selected) {
       // uncheck the 'time-based events' checkbox
@@ -30,14 +30,14 @@ bdd.describe('user input reactions', function () {
     })
     // try to find the checkbox (this shouldn fail)
     .then(function () {
-      let waitTime = 10000;
+      const waitTime = 10000;
       return PageObjects.settings.getTimeBasedIndexPatternCheckbox(waitTime);
     })
     .then(function () {
       PageObjects.common.saveScreenshot('Settings-indices-hide-time-based-index-pattern');
       // we expect the promise above to fail
-      let handler = PageObjects.common.createErrorHandler(self);
-      let msg = 'Found time based index pattern checkbox';
+      const handler = PageObjects.common.createErrorHandler(self);
+      const msg = 'Found time based index pattern checkbox';
       handler(msg);
     })
     .catch(function () {
diff --git a/test/functional/apps/management/_index_pattern_create_delete.js b/test/functional/apps/management/_index_pattern_create_delete.js
index bcb08b23308ba..898b738c2b7ee 100644
--- a/test/functional/apps/management/_index_pattern_create_delete.js
+++ b/test/functional/apps/management/_index_pattern_create_delete.js
@@ -48,7 +48,7 @@ bdd.describe('creating and deleting default index', function describeIndexTests(
       return PageObjects.settings.getTableHeader()
       .then(function (headers) {
         PageObjects.common.debug('header.length = ' + headers.length);
-        let expectedHeaders = [
+        const expectedHeaders = [
           'name',
           'type',
           'format',
@@ -60,7 +60,7 @@ bdd.describe('creating and deleting default index', function describeIndexTests(
         // 6 name   type  format  analyzed  indexed   controls
         expect(headers.length).to.be(expectedHeaders.length);
 
-        let comparedHeaders = headers.map(function compareHead(header, i) {
+        const comparedHeaders = headers.map(function compareHead(header, i) {
           return header.getVisibleText()
           .then(function (text) {
             expect(text).to.be(expectedHeaders[i]);
@@ -74,7 +74,7 @@ bdd.describe('creating and deleting default index', function describeIndexTests(
 
   bdd.describe('index pattern deletion', function indexDelete() {
     bdd.before(function () {
-      let expectedAlertText = 'Are you sure you want to remove this index pattern?';
+      const expectedAlertText = 'Are you sure you want to remove this index pattern?';
       return PageObjects.settings.removeIndexPattern()
       .then(function (alertText) {
         PageObjects.common.saveScreenshot('Settings-indices-confirm-remove-index-pattern');
diff --git a/test/functional/apps/management/_index_pattern_popularity.js b/test/functional/apps/management/_index_pattern_popularity.js
index 6e8b09581b6c7..0085b0bea38fd 100644
--- a/test/functional/apps/management/_index_pattern_popularity.js
+++ b/test/functional/apps/management/_index_pattern_popularity.js
@@ -27,7 +27,7 @@ bdd.describe('index result popularity', function describeIndexTests() {
   });
 
   bdd.describe('change popularity', function indexPatternCreation() {
-    let fieldName = 'geo.coordinates';
+    const fieldName = 'geo.coordinates';
 
     // set the page size to All again, https://github.com/elastic/kibana/issues/5030
     // TODO: remove this after issue #5030 is closed
diff --git a/test/functional/apps/management/_index_pattern_results_sort.js b/test/functional/apps/management/_index_pattern_results_sort.js
index f84dada2e2008..263628f9430cb 100644
--- a/test/functional/apps/management/_index_pattern_results_sort.js
+++ b/test/functional/apps/management/_index_pattern_results_sort.js
@@ -16,7 +16,7 @@ bdd.describe('index result field sort', function describeIndexTests() {
     return esClient.deleteAndUpdateConfigDoc();
   });
 
-  let columns = [{
+  const columns = [{
     heading: 'name',
     first: '@message',
     last: 'xss.raw',
@@ -77,10 +77,10 @@ bdd.describe('index result field sort', function describeIndexTests() {
   });
 
   bdd.describe('field list pagination', function () {
-    let expectedDefaultPageSize = 25;
-    let expectedFieldCount = 85;
-    let expectedLastPageCount = 10;
-    let pages = [1, 2, 3, 4];
+    const expectedDefaultPageSize = 25;
+    const expectedFieldCount = 85;
+    const expectedLastPageCount = 10;
+    const pages = [1, 2, 3, 4];
 
     bdd.before(function () {
       return PageObjects.settings.navigateTo()
@@ -110,8 +110,8 @@ bdd.describe('index result field sort', function describeIndexTests() {
     });
 
     bdd.it('should have the correct number of rows per page', function () {
-      let pageCount = Math.ceil(expectedFieldCount / expectedDefaultPageSize);
-      let chain = pages.reduce(function (chain, val) {
+      const pageCount = Math.ceil(expectedFieldCount / expectedDefaultPageSize);
+      const chain = pages.reduce(function (chain, val) {
         return chain.then(function () {
           return PageObjects.settings.goToPage(val)
           .then(function () {
@@ -122,7 +122,7 @@ bdd.describe('index result field sort', function describeIndexTests() {
           })
           .then(function (pageCount) {
             PageObjects.common.saveScreenshot('Settings-indices-paged');
-            let expectedSize = (val < 4) ? expectedDefaultPageSize : expectedLastPageCount;
+            const expectedSize = (val < 4) ? expectedDefaultPageSize : expectedLastPageCount;
             expect(pageCount.length).to.be(expectedSize);
           });
         });
diff --git a/test/functional/apps/management/_initial_state.js b/test/functional/apps/management/_initial_state.js
index e8d6258b85eec..01c5548d74eae 100644
--- a/test/functional/apps/management/_initial_state.js
+++ b/test/functional/apps/management/_initial_state.js
@@ -37,7 +37,7 @@ bdd.describe('initial state', function () {
   });
 
   bdd.it('should contain default index pattern', function () {
-    let defaultPattern = 'logstash-*';
+    const defaultPattern = 'logstash-*';
 
     return PageObjects.settings.getIndexPatternField().getProperty('value')
     .then(function (pattern) {
diff --git a/test/functional/apps/visualize/_area_chart.js b/test/functional/apps/visualize/_area_chart.js
index a6c257eb16ae3..e5e897851b051 100644
--- a/test/functional/apps/visualize/_area_chart.js
+++ b/test/functional/apps/visualize/_area_chart.js
@@ -10,8 +10,8 @@ import PageObjects from '../../../support/page_objects';
 
 bdd.describe('visualize app', function describeIndexTests() {
   bdd.before(function () {
-    let fromTime = '2015-09-19 06:31:44.000';
-    let toTime = '2015-09-23 18:31:44.000';
+    const fromTime = '2015-09-19 06:31:44.000';
+    const toTime = '2015-09-23 18:31:44.000';
 
     PageObjects.common.debug('navigateToApp visualize');
     return PageObjects.common.navigateToApp('visualize')
@@ -60,7 +60,7 @@ bdd.describe('visualize app', function describeIndexTests() {
   });
 
   bdd.describe('area charts', function indexPatternCreation() {
-    let vizName1 = 'Visualization AreaChart';
+    const vizName1 = 'Visualization AreaChart';
 
     bdd.it('should save and load with special characters', function pageHeader() {
       const vizNamewithSpecialChars = vizName1 + '/?&=%';
@@ -99,12 +99,12 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show correct chart, take screenshot', function pageHeader() {
-      let chartHeight = 0;
-      let xAxisLabels = [ '2015-09-20 00:00', '2015-09-21 00:00',
+      const chartHeight = 0;
+      const xAxisLabels = [ '2015-09-20 00:00', '2015-09-21 00:00',
         '2015-09-22 00:00', '2015-09-23 00:00'
       ];
-      let yAxisLabels = ['0','200','400','600','800','1,000','1,200','1,400','1,600'];
-      let expectedAreaChartData = [37, 202, 740, 1437, 1371, 751, 188, 31, 42, 202,
+      const yAxisLabels = ['0','200','400','600','800','1,000','1,200','1,400','1,600'];
+      const expectedAreaChartData = [37, 202, 740, 1437, 1371, 751, 188, 31, 42, 202,
         683, 1361, 1415, 707, 177, 27, 32, 175, 707, 1408, 1355, 726, 201, 29
       ];
 
@@ -134,7 +134,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data', function pageHeader() {
-      let expectedTableData = [ 'September 20th 2015, 00:00:00.000 37',
+      const expectedTableData = [ 'September 20th 2015, 00:00:00.000 37',
         'September 20th 2015, 03:00:00.000 202',
         'September 20th 2015, 06:00:00.000 740',
         'September 20th 2015, 09:00:00.000 1,437',
diff --git a/test/functional/apps/visualize/_chart_types.js b/test/functional/apps/visualize/_chart_types.js
index 2f3bee327fb21..4e3bd0c089a69 100644
--- a/test/functional/apps/visualize/_chart_types.js
+++ b/test/functional/apps/visualize/_chart_types.js
@@ -17,7 +17,7 @@ bdd.describe('visualize app', function describeIndexTests() {
 
   bdd.describe('chart types', function indexPatternCreation() {
     bdd.it('should show the correct chart types', function pageHeader() {
-      let expectedChartTypes = [
+      const expectedChartTypes = [
         'Area chart', 'Data table', 'Line chart', 'Markdown widget',
         'Metric', 'Pie chart', 'Tile map', 'Vertical bar chart'
       ];
diff --git a/test/functional/apps/visualize/_data_table.js b/test/functional/apps/visualize/_data_table.js
index ad241f01b60a8..f0681bd10608a 100644
--- a/test/functional/apps/visualize/_data_table.js
+++ b/test/functional/apps/visualize/_data_table.js
@@ -9,8 +9,8 @@ import {
 import PageObjects from '../../../support/page_objects';
 
 bdd.describe('visualize app', function describeIndexTests() {
-  let fromTime = '2015-09-19 06:31:44.000';
-  let toTime = '2015-09-23 18:31:44.000';
+  const fromTime = '2015-09-19 06:31:44.000';
+  const toTime = '2015-09-23 18:31:44.000';
 
   bdd.before(function () {
     PageObjects.common.debug('navigateToApp visualize');
@@ -52,7 +52,7 @@ bdd.describe('visualize app', function describeIndexTests() {
   });
 
   bdd.describe('data table', function indexPatternCreation() {
-    let vizName1 = 'Visualization DataTable';
+    const vizName1 = 'Visualization DataTable';
 
     bdd.it('should be able to save and load', function pageHeader() {
       return PageObjects.visualize.saveVisualization(vizName1)
@@ -72,8 +72,8 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data, take screenshot', function pageHeader() {
-      let chartHeight = 0;
-      let expectedChartData = [ '0 2,088', '2,000 2,748', '4,000 2,707', '6,000 2,876',
+      const chartHeight = 0;
+      const expectedChartData = [ '0 2,088', '2,000 2,748', '4,000 2,707', '6,000 2,876',
       '8,000 2,863', '10,000 147', '12,000 148', '14,000 129', '16,000 161', '18,000 137'
       ];
 
diff --git a/test/functional/apps/visualize/_line_chart.js b/test/functional/apps/visualize/_line_chart.js
index 53fc12f760930..4702622d6d03a 100644
--- a/test/functional/apps/visualize/_line_chart.js
+++ b/test/functional/apps/visualize/_line_chart.js
@@ -10,8 +10,8 @@ import PageObjects from '../../../support/page_objects';
 
 bdd.describe('visualize app', function describeIndexTests() {
   bdd.before(function () {
-    let fromTime = '2015-09-19 06:31:44.000';
-    let toTime = '2015-09-23 18:31:44.000';
+    const fromTime = '2015-09-19 06:31:44.000';
+    const toTime = '2015-09-23 18:31:44.000';
 
     PageObjects.common.debug('navigateToApp visualize');
     return PageObjects.common.navigateToApp('visualize')
@@ -51,10 +51,10 @@ bdd.describe('visualize app', function describeIndexTests() {
   });
 
   bdd.describe('line charts', function indexPatternCreation() {
-    let vizName1 = 'Visualization LineChart';
+    const vizName1 = 'Visualization LineChart';
 
     bdd.it('should be able to save and load', function pageHeader() {
-      let remote = this.remote;
+      const remote = this.remote;
 
       return PageObjects.visualize.saveVisualization(vizName1)
       .then(function (message) {
@@ -75,11 +75,11 @@ bdd.describe('visualize app', function describeIndexTests() {
 
     bdd.it('should show correct chart, take screenshot', function pageHeader() {
 
-      let remote = this.remote;
+      const remote = this.remote;
 
       // this test only verifies the numerical part of this data
       // it could also check the legend to verify the extensions
-      let expectedChartData = ['jpg 9,109', 'css 2,159', 'png 1,373', 'gif 918', 'php 445'];
+      const expectedChartData = ['jpg 9,109', 'css 2,159', 'png 1,373', 'gif 918', 'php 445'];
 
       // sleep a bit before trying to get the chart data
       return PageObjects.common.sleep(3000)
@@ -87,7 +87,7 @@ bdd.describe('visualize app', function describeIndexTests() {
         return PageObjects.visualize.getLineChartData('fill="#57c17b"')
         .then(function showData(data) {
           PageObjects.common.saveScreenshot('Visualize-line-chart');
-          let tolerance = 10; // the y-axis scale is 10000 so 10 is 0.1%
+          const tolerance = 10; // the y-axis scale is 10000 so 10 is 0.1%
           for (let x = 0; x < data.length; x++) {
             PageObjects.common.debug('x=' + x + ' expectedChartData[x].split(\' \')[1] = ' +
               (expectedChartData[x].split(' ')[1]).replace(',', '') + '  data[x]=' + data[x] +
@@ -101,8 +101,8 @@ bdd.describe('visualize app', function describeIndexTests() {
 
     bdd.it('should show correct data', function pageHeader() {
 
-      let remote = this.remote;
-      let expectedChartData = ['jpg 9,109', 'css 2,159', 'png 1,373', 'gif 918', 'php 445'];
+      const remote = this.remote;
+      const expectedChartData = ['jpg 9,109', 'css 2,159', 'png 1,373', 'gif 918', 'php 445'];
 
       return PageObjects.visualize.collapseChart()
       .then(function getDataTableData() {
diff --git a/test/functional/apps/visualize/_metric_chart.js b/test/functional/apps/visualize/_metric_chart.js
index 341335b4b5217..63a000bace10a 100644
--- a/test/functional/apps/visualize/_metric_chart.js
+++ b/test/functional/apps/visualize/_metric_chart.js
@@ -9,8 +9,8 @@ import {
 import PageObjects from '../../../support/page_objects';
 
 bdd.describe('visualize app', function describeIndexTests() {
-  let fromTime = '2015-09-19 06:31:44.000';
-  let toTime = '2015-09-23 18:31:44.000';
+  const fromTime = '2015-09-19 06:31:44.000';
+  const toTime = '2015-09-23 18:31:44.000';
 
   bdd.before(function () {
     PageObjects.common.debug('navigateToApp visualize');
@@ -31,7 +31,7 @@ bdd.describe('visualize app', function describeIndexTests() {
   bdd.describe('metric chart', function indexPatternCreation() {
 
     bdd.it('should show Count', function pageHeader() {
-      let expectedCount = ['14,004', 'Count'];
+      const expectedCount = ['14,004', 'Count'];
 
       // initial metric of "Count" is selected by default
       return PageObjects.common.try(function tryingForTime() {
@@ -44,7 +44,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Average', function pageHeader() {
-      let avgMachineRam = ['13,104,036,080.615', 'Average machine.ram'];
+      const avgMachineRam = ['13,104,036,080.615', 'Average machine.ram'];
       return PageObjects.visualize.clickMetricEditor()
       .then(function () {
         PageObjects.common.debug('Aggregation = Average');
@@ -68,7 +68,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Sum', function pageHeader() {
-      let sumPhpMemory = ['85,865,880', 'Sum of phpmemory'];
+      const sumPhpMemory = ['85,865,880', 'Sum of phpmemory'];
       PageObjects.common.debug('Aggregation = Sum');
       return PageObjects.visualize.selectAggregation('Sum')
       .then(function selectField() {
@@ -89,7 +89,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Median', function pageHeader() {
-      let medianBytes = ['5,565.263', '50th percentile of bytes'];
+      const medianBytes = ['5,565.263', '50th percentile of bytes'];
       //  For now, only comparing the text label part of the metric
       PageObjects.common.debug('Aggregation = Median');
       return PageObjects.visualize.selectAggregation('Median')
@@ -112,7 +112,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Min', function pageHeader() {
-      let minTimestamp = ['September 20th 2015, 00:00:00.000', 'Min @timestamp'];
+      const minTimestamp = ['September 20th 2015, 00:00:00.000', 'Min @timestamp'];
       PageObjects.common.debug('Aggregation = Min');
       return PageObjects.visualize.selectAggregation('Min')
       .then(function selectField() {
@@ -133,7 +133,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Max', function pageHeader() {
-      let maxRelatedContentArticleModifiedTime = ['April 4th 2015, 00:54:41.000', 'Max relatedContent.article:modified_time'];
+      const maxRelatedContentArticleModifiedTime = ['April 4th 2015, 00:54:41.000', 'Max relatedContent.article:modified_time'];
       PageObjects.common.debug('Aggregation = Max');
       return PageObjects.visualize.selectAggregation('Max')
       .then(function selectField() {
@@ -154,7 +154,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Standard Deviation', function pageHeader() {
-      let standardDeviationBytes = [
+      const standardDeviationBytes = [
         '-1,435.138', 'Lower Standard Deviation of bytes',
         '12,889.766', 'Upper Standard Deviation of bytes'
       ];
@@ -178,7 +178,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Unique Count', function pageHeader() {
-      let uniqueCountClientip = ['1,000', 'Unique count of clientip'];
+      const uniqueCountClientip = ['1,000', 'Unique count of clientip'];
       PageObjects.common.debug('Aggregation = Unique Count');
       return PageObjects.visualize.selectAggregation('Unique Count')
       .then(function selectField() {
@@ -206,7 +206,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Percentiles', function pageHeader() {
-      let percentileMachineRam = [
+      const percentileMachineRam = [
         '2,147,483,648', '1st percentile of machine.ram',
         '3,221,225,472', '5th percentile of machine.ram',
         '7,516,192,768', '25th percentile of machine.ram',
@@ -236,7 +236,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show Percentile Ranks', function pageHeader() {
-      let percentileRankBytes = [ '2.036%', 'Percentile rank 99 of "memory"'];
+      const percentileRankBytes = [ '2.036%', 'Percentile rank 99 of "memory"'];
       PageObjects.common.debug('Aggregation = Percentile Ranks');
       return PageObjects.visualize.selectAggregation('Percentile Ranks')
       .then(function selectField() {
diff --git a/test/functional/apps/visualize/_pie_chart.js b/test/functional/apps/visualize/_pie_chart.js
index 38fd7e1977156..eb940e7ec9d83 100644
--- a/test/functional/apps/visualize/_pie_chart.js
+++ b/test/functional/apps/visualize/_pie_chart.js
@@ -10,8 +10,8 @@ import PageObjects from '../../../support/page_objects';
 
 bdd.describe('visualize app', function describeIndexTests() {
   bdd.before(function () {
-    let fromTime = '2015-09-19 06:31:44.000';
-    let toTime = '2015-09-23 18:31:44.000';
+    const fromTime = '2015-09-19 06:31:44.000';
+    const toTime = '2015-09-23 18:31:44.000';
 
     PageObjects.common.debug('navigateToApp visualize');
     return PageObjects.common.navigateToApp('visualize')
@@ -59,10 +59,10 @@ bdd.describe('visualize app', function describeIndexTests() {
 
 
   bdd.describe('pie chart', function indexPatternCreation() {
-    let vizName1 = 'Visualization PieChart';
+    const vizName1 = 'Visualization PieChart';
 
     bdd.it('should save and load', function pageHeader() {
-      let remote = this.remote;
+      const remote = this.remote;
 
       return PageObjects.visualize.saveVisualization(vizName1)
       .then(function (message) {
@@ -85,12 +85,12 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show 10 slices in pie chart, take screenshot', function pageHeader() {
-      let remote = this.remote;
-      let expectedPieChartSliceCount = 10;
+      const remote = this.remote;
+      const expectedPieChartSliceCount = 10;
 
       return PageObjects.visualize.getPieChartData()
       .then(function (pieData) {
-        let barHeightTolerance = 1;
+        const barHeightTolerance = 1;
         PageObjects.common.debug('pieData.length = ' + pieData.length);
         PageObjects.common.saveScreenshot('Visualize-pie-chart');
         expect(pieData.length).to.be(expectedPieChartSliceCount);
@@ -98,8 +98,8 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show correct data', function pageHeader() {
-      let remote = this.remote;
-      let expectedTableData =  [ '0 55', '40,000 50', '80,000 41', '120,000 43',
+      const remote = this.remote;
+      const expectedTableData =  [ '0 55', '40,000 50', '80,000 41', '120,000 43',
         '160,000 44', '200,000 40', '240,000 46', '280,000 39', '320,000 40', '360,000 47'
       ];
 
diff --git a/test/functional/apps/visualize/_tile_map.js b/test/functional/apps/visualize/_tile_map.js
index 1e34697c5aa95..b9b46196693a7 100644
--- a/test/functional/apps/visualize/_tile_map.js
+++ b/test/functional/apps/visualize/_tile_map.js
@@ -9,8 +9,8 @@ import {
 import PageObjects from '../../../support/page_objects';
 
 bdd.describe('visualize app', function describeIndexTests() {
-  let fromTime = '2015-09-19 06:31:44.000';
-  let toTime = '2015-09-23 18:31:44.000';
+  const fromTime = '2015-09-19 06:31:44.000';
+  const toTime = '2015-09-23 18:31:44.000';
 
   bdd.before(function () {
 
@@ -52,7 +52,7 @@ bdd.describe('visualize app', function describeIndexTests() {
   bdd.describe('tile map chart', function indexPatternCreation() {
 
     bdd.it('should show correct tile map data on default zoom level', function pageHeader() {
-      let expectedTableData = [ 'dn 1,429', 'dp 1,418', '9y 1,215', '9z 1,099', 'dr 1,076',
+      const expectedTableData = [ 'dn 1,429', 'dp 1,418', '9y 1,215', '9z 1,099', 'dr 1,076',
         'dj 982', '9v 938', '9q 722', '9w 475', 'cb 457', 'c2 453', '9x 420', 'dq 399',
         '9r 396', '9t 274', 'c8 271', 'dh 214', 'b6 207', 'bd 206', 'b7 167', 'f0 141',
         'be 128', '9m 126', 'bf 85', 'de 73', 'bg 71', '9p 71', 'c1 57', 'c4 50', '9u 48',
@@ -75,7 +75,7 @@ bdd.describe('visualize app', function describeIndexTests() {
 
 
     bdd.it('should zoom out to level 1 from default level 2', function pageHeader() {
-      let expectedPrecision2Circles =  [ { color: '#750000', radius: 48 },
+      const expectedPrecision2Circles =  [ { color: '#750000', radius: 48 },
         { color: '#750000', radius: 48 },
         { color: '#750000', radius: 44 },
         { color: '#a40000', radius: 42 },
@@ -143,7 +143,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('"Fit data bounds" should zoom to level 3', function pageHeader() {
-      let expectedPrecision2ZoomCircles =   [ { color: '#750000', radius: 192 },
+      const expectedPrecision2ZoomCircles =   [ { color: '#750000', radius: 192 },
         { color: '#750000', radius: 191 },
         { color: '#750000', radius: 177 },
         { color: '#a40000', radius: 168 },
@@ -206,12 +206,12 @@ bdd.describe('visualize app', function describeIndexTests() {
     ** changed, then open the saved viz and check that it's back to the original data.
     */
     bdd.it('should save with zoom level and load, take screenshot', function pageHeader() {
-      let vizName1 = 'Visualization TileMap';
-      let expectedTableData =  [ 'dr4 127', 'dr7 92', '9q5 91', '9qc 89', 'drk 87',
+      const vizName1 = 'Visualization TileMap';
+      const expectedTableData =  [ 'dr4 127', 'dr7 92', '9q5 91', '9qc 89', 'drk 87',
         'dps 82', 'dph 82', 'dp3 79', 'dpe 78', 'dp8 77'
       ];
 
-      let expectedTableDataZoomed = [ 'dr5r 21', 'dps8 20', '9q5b 19', 'b6uc 17',
+      const expectedTableDataZoomed = [ 'dr5r 21', 'dps8 20', '9q5b 19', 'b6uc 17',
         '9y63 17', 'c20g 16', 'dqfz 15', 'dr8h 14', 'dp8p 14', 'dp3k 14'
       ];
 
diff --git a/test/functional/apps/visualize/_vertical_bar_chart.js b/test/functional/apps/visualize/_vertical_bar_chart.js
index 1161a7d8daa31..5a419492fad6e 100644
--- a/test/functional/apps/visualize/_vertical_bar_chart.js
+++ b/test/functional/apps/visualize/_vertical_bar_chart.js
@@ -9,8 +9,8 @@ import {
 import PageObjects from '../../../support/page_objects';
 
 bdd.describe('visualize app', function describeIndexTests() {
-  let fromTime = '2015-09-19 06:31:44.000';
-  let toTime = '2015-09-23 18:31:44.000';
+  const fromTime = '2015-09-19 06:31:44.000';
+  const toTime = '2015-09-23 18:31:44.000';
 
   bdd.before(function () {
     PageObjects.common.debug('navigateToApp visualize');
@@ -51,7 +51,7 @@ bdd.describe('visualize app', function describeIndexTests() {
   });
 
   bdd.describe('vertical bar chart', function indexPatternCreation() {
-    let vizName1 = 'Visualization VerticalBarChart';
+    const vizName1 = 'Visualization VerticalBarChart';
 
     bdd.it('should save and load', function pageHeader() {
       return PageObjects.visualize.saveVisualization(vizName1)
@@ -74,7 +74,7 @@ bdd.describe('visualize app', function describeIndexTests() {
     });
 
     bdd.it('should show correct chart, take screenshot', function pageHeader() {
-      let expectedChartValues = [37, 202, 740, 1437, 1371, 751, 188, 31, 42, 202, 683,
+      const expectedChartValues = [37, 202, 740, 1437, 1371, 751, 188, 31, 42, 202, 683,
         1361, 1415, 707, 177, 27, 32, 175, 707, 1408, 1355, 726, 201, 29
       ];
 
@@ -96,7 +96,7 @@ bdd.describe('visualize app', function describeIndexTests() {
 
     bdd.it('should show correct data', function pageHeader() {
       // this is only the first page of the tabular data.
-      let expectedChartData =  [ 'September 20th 2015, 00:00:00.000 37',
+      const expectedChartData =  [ 'September 20th 2015, 00:00:00.000 37',
         'September 20th 2015, 03:00:00.000 202',
         'September 20th 2015, 06:00:00.000 740',
         'September 20th 2015, 09:00:00.000 1,437',
diff --git a/test/functional/apps/visualize/index.js b/test/functional/apps/visualize/index.js
index 2ad3ec18c6441..342fbcb8faf92 100644
--- a/test/functional/apps/visualize/index.js
+++ b/test/functional/apps/visualize/index.js
@@ -16,11 +16,11 @@ bdd.describe('visualize app', function () {
   this.timeout = defaultTimeout;
 
   bdd.before(function () {
-    let self = this;
+    const self = this;
     remote.setWindowSize(1200,800);
 
     PageObjects.common.debug('Starting visualize before method');
-    let logstash = scenarioManager.loadIfEmpty('logstashFunctional');
+    const logstash = scenarioManager.loadIfEmpty('logstashFunctional');
     // delete .kibana index and update configDoc
     return esClient.deleteAndUpdateConfigDoc({'dateFormat:tz':'UTC', 'defaultIndex':'logstash-*'})
     .then(function loadkibanaIndexPattern() {
diff --git a/test/functional/status_page/index.js b/test/functional/status_page/index.js
index d1f6f0b37c5ae..c36d5223c6561 100644
--- a/test/functional/status_page/index.js
+++ b/test/functional/status_page/index.js
@@ -4,7 +4,7 @@ import {
 
 import PageObjects from '../../support/page_objects';
 
-let expect = require('expect.js');
+const expect = require('expect.js');
 
 bdd.describe('status page', function () {
   bdd.before(function () {
@@ -12,7 +12,7 @@ bdd.describe('status page', function () {
   });
 
   bdd.it('should show the kibana plugin as ready', function () {
-    let self = this;
+    const self = this;
 
     return PageObjects.common.tryForTime(6000, function () {
       return PageObjects.common.findTestSubject('statusBreakdown')
diff --git a/test/mocha_setup.js b/test/mocha_setup.js
index 24acc31cefd35..755211ac523a0 100644
--- a/test/mocha_setup.js
+++ b/test/mocha_setup.js
@@ -1,5 +1,5 @@
-let sinon = require('sinon');
-let autoRelease = require('auto-release-sinon');
+const sinon = require('sinon');
+const autoRelease = require('auto-release-sinon');
 
 require('babel/register')(require('../src/optimize/babel_options').node);
 
@@ -13,7 +13,7 @@ require('babel/register')(require('../src/optimize/babel_options').node);
 // The global "afterEach" variable is also tracked, and once it is assigned by mocha
 // the variable global is reconfigured to point directly to the new value (from mocha)
 // and all of the queued invocations are executed.
-let queuedAfterEachArgs = [];
+const queuedAfterEachArgs = [];
 Object.defineProperty(global, 'afterEach', {
   configurable: true,
   get() { return undefined; },
diff --git a/test/server_config.js b/test/server_config.js
index ee82cbe035196..ea1208ed05017 100644
--- a/test/server_config.js
+++ b/test/server_config.js
@@ -1,6 +1,6 @@
-let shield = require('./shield');
+const shield = require('./shield');
 
-let kibanaURL = '/app/kibana';
+const kibanaURL = '/app/kibana';
 
 module.exports = {
   servers: {
diff --git a/test/support/env_setup.js b/test/support/env_setup.js
index 25683e344da0d..37f8d5b1de0c2 100644
--- a/test/support/env_setup.js
+++ b/test/support/env_setup.js
@@ -1,4 +1,4 @@
-let defaults = require('lodash').defaults;
+const defaults = require('lodash').defaults;
 const babelOptions = require('../../src/optimize/babel_options');
 
 require('source-map-support').install();
diff --git a/test/support/page_objects/common.js b/test/support/page_objects/common.js
index e7e3731b49a03..d197299d1db74 100644
--- a/test/support/page_objects/common.js
+++ b/test/support/page_objects/common.js
@@ -35,7 +35,7 @@ export default class Common {
 
   init(remote) {
     function injectTimestampQuery(func, url) {
-      let formatted = modifyQueryString(url, function (parsed) {
+      const formatted = modifyQueryString(url, function (parsed) {
         parsed.query._t = Date.now();
       });
       return func.call(this, formatted);
@@ -51,7 +51,7 @@ export default class Common {
     }
 
     function modifyQueryString(url, func) {
-      let parsed = parse(url, true);
+      const parsed = parse(url, true);
       if (parsed.query === null) {
         parsed.query = {};
       }
@@ -76,8 +76,8 @@ export default class Common {
   }
 
   navigateToApp(appName, testStatusPage) {
-    let self = this;
-    let appUrl = getUrl.noAuth(config.servers.kibana, config.apps[appName]);
+    const self = this;
+    const appUrl = getUrl.noAuth(config.servers.kibana, config.apps[appName]);
     self.debug('navigating to ' + appName + ' url: ' + appUrl);
 
     function navigateTo(url) {
@@ -100,7 +100,7 @@ export default class Common {
             .then(function (kibanaLoaded) {
               self.debug('kibanaLoaded = ' + kibanaLoaded);
               if (!kibanaLoaded) {
-                let msg = 'Kibana is not loaded, retrying';
+                const msg = 'Kibana is not loaded, retrying';
                 self.debug(msg);
                 throw new Error(msg);
               }
@@ -111,7 +111,7 @@ export default class Common {
           return self.remote.getCurrentUrl();
         })
         .then(function (currentUrl) {
-          let loginPage = new RegExp('login').test(currentUrl);
+          const loginPage = new RegExp('login').test(currentUrl);
           if (loginPage) {
             self.debug('Found loginPage = ' + loginPage + ', username = '
               + config.servers.kibana.shield.username);
@@ -126,7 +126,7 @@ export default class Common {
         })
         .then(function (currentUrl) {
           currentUrl = currentUrl.replace(/\/\/\w+:\w+@/, '//');
-          let maxAdditionalLengthOnNavUrl = 230;
+          const maxAdditionalLengthOnNavUrl = 230;
           // On several test failures at the end of the TileMap test we try to navigate back to
           // Visualize so we can create the next Vertical Bar Chart, but we can see from the
           // logging and the screenshot that it's still on the TileMap page. Why didn't the "get"
@@ -137,11 +137,11 @@ export default class Common {
           // Navigating to Settings when there is a default index pattern has a URL length of 196
           // (from debug output). Some other tabs may also be long. But a rather simple configured
           // visualization is about 1000 chars long. So at least we catch that case.
-          let navSuccessful = new RegExp(appUrl + '.{0,' + maxAdditionalLengthOnNavUrl + '}$')
+          const navSuccessful = new RegExp(appUrl + '.{0,' + maxAdditionalLengthOnNavUrl + '}$')
           .test(currentUrl);
 
           if (!navSuccessful) {
-            let msg = 'App failed to load: ' + appName +
+            const msg = 'App failed to load: ' + appName +
             ' in ' + defaultFindTimeout + 'ms' +
             ' appUrl = ' + appUrl +
             ' currentUrl = ' + currentUrl;
@@ -175,7 +175,7 @@ export default class Common {
   }
 
   runScript(fn, timeout) {
-    let self = this;
+    const self = this;
     // by default, give the app 10 seconds to load
     timeout = timeout || 10000;
 
@@ -183,9 +183,9 @@ export default class Common {
     return self.remote
     .setExecuteAsyncTimeout(timeout)
     .executeAsync(function (done) {
-      let interval = setInterval(function () {
-        let ready = (document.readyState === 'complete');
-        let hasJQuery = !!window.$;
+      const interval = setInterval(function () {
+        const ready = (document.readyState === 'complete');
+        const hasJQuery = !!window.$;
 
         if (ready && hasJQuery) {
           console.log('doc ready, jquery loaded');
@@ -199,25 +199,25 @@ export default class Common {
   }
 
   getApp() {
-    let self = this;
+    const self = this;
 
     return self.remote.setFindTimeout(defaultFindTimeout)
     .findByCssSelector('.app-wrapper .application')
     .then(function () {
       return self.runScript(function () {
-        let $ = window.$;
-        let $scope = $('.app-wrapper .application').scope();
+        const $ = window.$;
+        const $scope = $('.app-wrapper .application').scope();
         return $scope ? $scope.chrome.getApp() : {};
       });
     });
   }
 
   checkForKibanaApp() {
-    let self = this;
+    const self = this;
 
     return self.getApp()
     .then(function (app) {
-      let appId = app.id;
+      const appId = app.id;
       self.debug('current application: ' + appId);
       return appId === 'kibana';
     })
@@ -246,7 +246,7 @@ export default class Common {
   }
 
   sleep(sleepMilliseconds) {
-    let self = this;
+    const self = this;
     self.debug('... sleep(' + sleepMilliseconds + ') start');
 
     return bluebird.resolve().delay(sleepMilliseconds)
diff --git a/test/support/page_objects/console_page.js b/test/support/page_objects/console_page.js
index a18668b4eaac7..afd75f6c46dd7 100644
--- a/test/support/page_objects/console_page.js
+++ b/test/support/page_objects/console_page.js
@@ -32,7 +32,7 @@ export default class ConsolePage {
         return line.getVisibleText();
       }
 
-      let getEditorDataPromises = editorData.map(getEditorData);
+      const getEditorDataPromises = editorData.map(getEditorData);
       return Promise.all(getEditorDataPromises);
     });
   }
diff --git a/test/support/page_objects/dashboard_page.js b/test/support/page_objects/dashboard_page.js
index bac3c80d49c93..edb32e7cf9c6b 100644
--- a/test/support/page_objects/dashboard_page.js
+++ b/test/support/page_objects/dashboard_page.js
@@ -124,7 +124,7 @@ export default class DashboardPage {
   // use the search filter box to narrow the results down to a single
   // entry, or at least to a single page of results
   loadSavedDashboard(dashName) {
-    let self = this;
+    const self = this;
     return this.findTimeout
     .findByCssSelector('button.ng-scope[aria-label="Load Saved Dashboard"]')
     .click()
@@ -160,7 +160,7 @@ export default class DashboardPage {
         return chart.getAttribute('title');
       }
 
-      let getTitlePromises = titleObjects.map(getTitles);
+      const getTitlePromises = titleObjects.map(getTitles);
       return Promise.all(getTitlePromises);
     });
   }
@@ -211,7 +211,7 @@ export default class DashboardPage {
         });
       }
 
-      let getTitlePromises = titleObjects.map(getTitles);
+      const getTitlePromises = titleObjects.map(getTitles);
       return Promise.all(getTitlePromises);
     });
   }
diff --git a/test/support/page_objects/discover_page.js b/test/support/page_objects/discover_page.js
index d03fd696cde03..c65edec358998 100644
--- a/test/support/page_objects/discover_page.js
+++ b/test/support/page_objects/discover_page.js
@@ -88,7 +88,7 @@ export default class DiscoverPage {
         .getAttribute('height');
       }
 
-      let getChartDataPromises = chartData.map(getChartData);
+      const getChartDataPromises = chartData.map(getChartData);
       return Promise.all(getChartDataPromises);
     })
     .then(function (bars) {
diff --git a/test/support/page_objects/header_page.js b/test/support/page_objects/header_page.js
index 05db918f09e2d..1c6d23aa69e46 100644
--- a/test/support/page_objects/header_page.js
+++ b/test/support/page_objects/header_page.js
@@ -73,7 +73,7 @@ export default class HeaderPage {
   }
 
   clickGoButton() {
-    let self = this;
+    const self = this;
     return this.remote.setFindTimeout(defaultFindTimeout)
     .findByClassName('kbn-timepicker-go')
     .click()
diff --git a/test/support/page_objects/settings_page.js b/test/support/page_objects/settings_page.js
index c9982943c9be2..4b9f09bb0c0ce 100644
--- a/test/support/page_objects/settings_page.js
+++ b/test/support/page_objects/settings_page.js
@@ -41,7 +41,7 @@ export default class SettingsPage {
   }
 
   setAdvancedSettings(propertyName, propertyValue) {
-    let self = this;
+    const self = this;
 
     return PageObjects.common.findTestSubject('advancedSetting&' + propertyName + ' editButton')
     .click()
@@ -69,7 +69,7 @@ export default class SettingsPage {
   }
 
   getAdvancedSettings(propertyName) {
-    let self = this;
+    const self = this;
     PageObjects.common.debug('in setAdvancedSettings');
     return PageObjects.common.findTestSubject('advancedSetting&' + propertyName + ' currentValue')
     .getVisibleText();
@@ -177,7 +177,7 @@ export default class SettingsPage {
         });
       }
 
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Bluebird.all(getChartTypesPromises);
     });
   }
@@ -192,8 +192,8 @@ export default class SettingsPage {
   }
 
   getFieldsTabCount() {
-    let self = this;
-    let selector = 'li.kbn-management-tab.active a small';
+    const self = this;
+    const selector = 'li.kbn-management-tab.active a small';
 
     return PageObjects.common.try(function () {
       return self.remote.setFindTimeout(defaultFindTimeout / 10)
@@ -211,7 +211,7 @@ export default class SettingsPage {
     .findAllByCssSelector('select.ng-pristine.ng-valid.ng-untouched option')
     .then(function (chartTypes) {
       function getChartType(chart) {
-        let thisChart = chart;
+        const thisChart = chart;
         return chart.isSelected()
         .then(function (isSelected) {
           if (isSelected === true) {
@@ -223,7 +223,7 @@ export default class SettingsPage {
         });
       }
 
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Bluebird.all(getChartTypesPromises);
     })
     .then(() => {
diff --git a/test/support/page_objects/shield_page.js b/test/support/page_objects/shield_page.js
index 529ef9c59ade0..a6d2ae956e8cb 100644
--- a/test/support/page_objects/shield_page.js
+++ b/test/support/page_objects/shield_page.js
@@ -10,7 +10,7 @@ export default class ShieldPage {
   }
 
   login(user, pwd) {
-    let remote = this.remote;
+    const remote = this.remote;
     return remote.setFindTimeout(defaultFindTimeout)
     .findById('username')
     .type(user)
diff --git a/test/support/page_objects/visualize_page.js b/test/support/page_objects/visualize_page.js
index 092592f6910f1..4422758b0d950 100644
--- a/test/support/page_objects/visualize_page.js
+++ b/test/support/page_objects/visualize_page.js
@@ -75,7 +75,7 @@ export default class VisualizePage {
   }
 
   getChartTypes() {
-    let types = [];
+    const types = [];
     return this.remote
     .setFindTimeout(defaultFindTimeout)
     .findAllByCssSelector('.wizard-type-heading h4')
@@ -83,7 +83,7 @@ export default class VisualizePage {
       function getChartType(chart) {
         return chart.getVisibleText();
       }
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Promise.all(getChartTypesPromises);
     })
     .then(function (texts) {
@@ -208,7 +208,7 @@ export default class VisualizePage {
           }
         });
       }
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Promise.all(getChartTypesPromises);
     });
   }
@@ -228,7 +228,7 @@ export default class VisualizePage {
   }
 
   selectField(fieldValue) {
-    let self = this;
+    const self = this;
     return PageObjects.common.try(function tryingForTime() {
       return self.remote
       .setFindTimeout(defaultFindTimeout)
@@ -350,7 +350,7 @@ export default class VisualizePage {
   }
 
   clickVisualizationByLinkText(vizName) {
-    let self = this;
+    const self = this;
     PageObjects.common.debug('clickVisualizationByLinkText(' + vizName + ')');
 
     return PageObjects.common.try(function tryingForTime() {
@@ -364,7 +364,7 @@ export default class VisualizePage {
   // this starts by clicking the Load Saved Viz button, not from the
   // bottom half of the "Create a new visualization      Step 1" page
   loadSavedVisualization(vizName) {
-    let self = this;
+    const self = this;
     return this.clickLoadSavedVisButton()
     .then(function filterVisualization() {
       return self.openSavedVisualization(vizName);
@@ -374,7 +374,7 @@ export default class VisualizePage {
   // this is for starting on the
   // bottom half of the "Create a new visualization      Step 1" page
   openSavedVisualization(vizName) {
-    let self = this;
+    const self = this;
     return self.filterVisByName(vizName)
     .then(() => {
       return PageObjects.common.sleep(1000);
@@ -393,7 +393,7 @@ export default class VisualizePage {
         return chart
         .getVisibleText();
       }
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Promise.all(getChartTypesPromises);
     })
     .then(texts => {
@@ -412,7 +412,7 @@ export default class VisualizePage {
         return chart
         .getVisibleText();
       }
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Promise.all(getChartTypesPromises);
     })
     .then(texts => {
@@ -428,12 +428,12 @@ export default class VisualizePage {
    */
   getAreaChartData(aggregateName) {
 
-    let self = this.remote;
-    let chartData = [];
+    const self = this.remote;
+    const chartData = [];
     let tempArray = [];
     let chartSections = 0;
-    let chartMap = {};
-    let height = 0;
+    const chartMap = {};
+    const height = 0;
     let yAxisLabel = 0;
     let yAxisHeight = 0;
 
@@ -485,7 +485,7 @@ export default class VisualizePage {
 
   // The current test shows dots, not a line.  This function gets the dots and normalizes their height.
   getLineChartData(cssPart) {
-    let self = this.remote;
+    const self = this.remote;
     let yAxisLabel = 0;
     let yAxisHeight;
 
@@ -535,7 +535,7 @@ export default class VisualizePage {
           }
 
           // 4). pass the chartTypes to the getChartType function
-          let getChartTypesPromises = chartTypes.map(getChartType);
+          const getChartTypesPromises = chartTypes.map(getChartType);
           return Promise.all(getChartTypesPromises);
         });
       })
@@ -548,7 +548,7 @@ export default class VisualizePage {
 
   // this is ALMOST identical to DiscoverPage.getBarChartData
   getBarChartData() {
-    let self = this.remote;
+    const self = this.remote;
     let yAxisLabel = 0;
     let yAxisHeight;
 
@@ -601,7 +601,7 @@ export default class VisualizePage {
             }
           });
         }
-        let getChartTypesPromises = chartTypes.map(getChartType);
+        const getChartTypesPromises = chartTypes.map(getChartType);
         return Promise.all(getChartTypesPromises);
       })
       .then(function (bars) {
@@ -611,7 +611,7 @@ export default class VisualizePage {
   }
 
   getPieChartData() {
-    let self = this.remote;
+    const self = this.remote;
 
     // 1). get the maximim chart Y-Axis marker value
     return this.remote
@@ -626,7 +626,7 @@ export default class VisualizePage {
           return slice;
         });
       }
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Promise.all(getChartTypesPromises);
     })
     .then(function (slices) {
@@ -670,7 +670,7 @@ export default class VisualizePage {
   }
 
   waitForToastMessageGone() {
-    let self = this;
+    const self = this;
     return PageObjects.common.try(function tryingForTime() {
       return self.remote
       .setFindTimeout(100)
@@ -760,7 +760,7 @@ export default class VisualizePage {
           return {color: color, radius: radius};
         });
       }
-      let getChartTypesPromises = chartTypes.map(getChartType);
+      const getChartTypesPromises = chartTypes.map(getChartType);
       return Promise.all(getChartTypesPromises);
     })
     .then((circles) => {
diff --git a/test/support/utils/elastic_dump.js b/test/support/utils/elastic_dump.js
index cb1f167523547..d947dd964455c 100644
--- a/test/support/utils/elastic_dump.js
+++ b/test/support/utils/elastic_dump.js
@@ -4,11 +4,11 @@ import {
 } from './';
 
 export default (function () {
-  let util = require('util');
-  let path = require('path');
-  let url = require('url');
-  let resolve = require('path').resolve;
-  let Elasticdump = require('elasticdump').elasticdump;
+  const util = require('util');
+  const path = require('path');
+  const url = require('url');
+  const resolve = require('path').resolve;
+  const Elasticdump = require('elasticdump').elasticdump;
 
   function ElasticDump() {
   }
@@ -22,7 +22,7 @@ export default (function () {
     */
     elasticdumpModule: function elasticdumpModule(myinput, myoutput, index, mytype) {
 
-      let options = {
+      const options = {
         limit:           100,
         offset:          0,
         debug:           false,
@@ -46,12 +46,12 @@ export default (function () {
         skip:            null,
         toLog:           null,
       };
-      let dumper = new Elasticdump(options.input, options.output, options);
+      const dumper = new Elasticdump(options.input, options.output, options);
 
       dumper.on('log',   function (message) { Log.debug(message); });
       dumper.on('error', function (error)   { Log.debug('error', 'Error Emitted => ' + (error.message || JSON.stringify(error))); });
 
-      let promise = new Promise(function (resolve, reject) {
+      const promise = new Promise(function (resolve, reject) {
         dumper.dump(function (error, totalWrites) {
           if (error) {
             Log.debug('THERE WAS AN ERROR :-(');
@@ -72,7 +72,7 @@ export default (function () {
     ** Fails if the files already exist, so consider appending a timestamp to filename.
     */
     elasticDump: function elasticDump(index, file) {
-      let self = this;
+      const self = this;
       Log.debug('Dumping mapping from ' + url.format(config.servers.elasticsearch) + '/' + index
         + ' to (' + file + '.mapping.json)');
       return this.elasticdumpModule(url.format(config.servers.elasticsearch),
@@ -94,7 +94,7 @@ export default (function () {
     elasticLoad: function elasticLoad(file, index) {
       // TODO: should we have a flag to delete the index first?
       // or use scenarioManager.unload(index) ? <<- currently this
-      let self = this;
+      const self = this;
       Log.debug('Loading mapping (test/fixtures/dump_data/' + file + '.mapping.json) into '
         + url.format(config.servers.elasticsearch) + '/' + index);
       return this.elasticdumpModule('test/fixtures/dump_data/' + file + '.mapping.json',
diff --git a/test/support/utils/es_client.js b/test/support/utils/es_client.js
index 1235bb3bb7247..15147822af5bd 100644
--- a/test/support/utils/es_client.js
+++ b/test/support/utils/es_client.js
@@ -6,8 +6,8 @@ import {
 
 export default (function () {
 
-  let elasticsearch = require('elasticsearch');
-  let Promise = require('bluebird');
+  const elasticsearch = require('elasticsearch');
+  const Promise = require('bluebird');
 
   function EsClient(server) {
     if (!server) throw new Error('No server defined');
@@ -81,9 +81,9 @@ export default (function () {
     */
     updateConfigDoc: function (docMap) {
       // first we need to get the config doc's id so we can use it in our _update call
-      let self = this;
+      const self = this;
       let configId;
-      let docMapString = JSON.stringify(docMap);
+      const docMapString = JSON.stringify(docMap);
 
       return this.getConfigId()
       // now that we have the id, we can update
@@ -110,7 +110,7 @@ export default (function () {
     * @return {Promise} A promise that is resolved when elasticsearch has a response
     */
     deleteAndUpdateConfigDoc: function (docMap) {
-      let self = this;
+      const self = this;
       let configId;
 
       return this.delete('.kibana')
@@ -120,7 +120,7 @@ export default (function () {
             return self.getConfigId();
           });
         } else {
-          let docMapString = JSON.stringify(docMap);
+          const docMapString = JSON.stringify(docMap);
           return Try.try(function () {
             return self.updateConfigDoc(docMap);
           });
diff --git a/test/support/utils/try.js b/test/support/utils/try.js
index 58ef7a57ef5eb..db22f04869b1e 100644
--- a/test/support/utils/try.js
+++ b/test/support/utils/try.js
@@ -10,9 +10,9 @@ import Log from './log.js';
 class Try {
 
   tryForTime(timeout, block) {
-    let self = this;
-    let start = Date.now();
-    let retryDelay = 502;
+    const self = this;
+    const start = Date.now();
+    const retryDelay = 502;
     let lastTry = 0;
     let tempMessage;
 
diff --git a/test/unit/api/ingest/_data.js b/test/unit/api/ingest/_data.js
index 8daffc34eb2f3..5d4a40376283c 100644
--- a/test/unit/api/ingest/_data.js
+++ b/test/unit/api/ingest/_data.js
@@ -1,9 +1,9 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
-  let fakeNamesIndexTemplate = require('intern/dojo/node!../../fixtures/fake_names_index_template.json');
-  let fs = require('intern/dojo/node!fs');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
+  const fakeNamesIndexTemplate = require('intern/dojo/node!../../fixtures/fake_names_index_template.json');
+  const fs = require('intern/dojo/node!fs');
 
   return function (bdd, scenarioManager, request) {
     const es = scenarioManager.client;
@@ -33,7 +33,7 @@ define(function (require) {
       });
 
       bdd.it('should also accept the raw csv data in the payload body', function () {
-        let csvData = fs.readFileSync('test/unit/fixtures/fake_names_big.csv', {encoding: 'utf8'});
+        const csvData = fs.readFileSync('test/unit/fixtures/fake_names_big.csv', {encoding: 'utf8'});
 
         return request.post('/kibana/names/_data')
         .send(csvData)
diff --git a/test/unit/api/ingest/_del.js b/test/unit/api/ingest/_del.js
index b310dc0df2944..6580777e47d43 100644
--- a/test/unit/api/ingest/_del.js
+++ b/test/unit/api/ingest/_del.js
@@ -1,8 +1,8 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let createTestData = require('intern/dojo/node!../../../unit/api/ingest/data');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const createTestData = require('intern/dojo/node!../../../unit/api/ingest/data');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
 
   return function (bdd, scenarioManager, request) {
diff --git a/test/unit/api/ingest/_post.js b/test/unit/api/ingest/_post.js
index 0b70c35ddeaea..46fe6488fa062 100644
--- a/test/unit/api/ingest/_post.js
+++ b/test/unit/api/ingest/_post.js
@@ -1,8 +1,8 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let createTestData = require('intern/dojo/node!../../../unit/api/ingest/data');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const createTestData = require('intern/dojo/node!../../../unit/api/ingest/data');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   return function (bdd, scenarioManager, request) {
     bdd.describe('POST ingest', function postIngest() {
@@ -101,7 +101,7 @@ define(function (require) {
               id: 'logstash-*'
             })
             .then(function (res) {
-              let fields = JSON.parse(res._source.fields);
+              const fields = JSON.parse(res._source.fields);
               // @timestamp was created with only name and type, all other fields should be set as defaults by API
               expect(res._source.title).to.be('logstash-*');
               expect(fields[1].name).to.be('@timestamp');
@@ -142,7 +142,7 @@ define(function (require) {
           .then(function () {
             return scenarioManager.client.indices.getTemplate({name: 'kibana-logstash-*'})
             .then(function (template) {
-              let mappings = template['kibana-logstash-*'].mappings._default_.properties;
+              const mappings = template['kibana-logstash-*'].mappings._default_.properties;
               expect(mappings).to.be.ok();
               expect(_.isEqual(mappings.ip, {index: true, type: 'ip', doc_values: true})).to.be.ok();
               expect(_.isEqual(mappings['@timestamp'], {index: true, type: 'date', doc_values: true})).to.be.ok();
@@ -220,7 +220,7 @@ define(function (require) {
 
       bdd.it('should return 409 conflict when the pattern matches existing indices',
         function existingIndicesConflict() {
-          let ingestConfig = createTestData();
+          const ingestConfig = createTestData();
           ingestConfig.index_pattern.id = ingestConfig.index_pattern.title = '.kib*';
 
           return request.post('/kibana/ingest')
@@ -229,7 +229,7 @@ define(function (require) {
         });
 
       bdd.it('should enforce snake_case in the request body', function () {
-        let ingestConfig = createTestData();
+        const ingestConfig = createTestData();
         ingestConfig.index_pattern = _.mapKeys(ingestConfig.index_pattern, function (value, key) {
           return _.camelCase(key);
         });
diff --git a/test/unit/api/ingest/_processors.js b/test/unit/api/ingest/_processors.js
index 3e1cb7d01e84b..8317efd16f12d 100644
--- a/test/unit/api/ingest/_processors.js
+++ b/test/unit/api/ingest/_processors.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   return function (bdd, scenarioManager, request) {
     bdd.describe('processors', () => {
diff --git a/test/unit/api/ingest/_simulate.js b/test/unit/api/ingest/_simulate.js
index 61a1e0e1ef312..f6329bcfbcfee 100644
--- a/test/unit/api/ingest/_simulate.js
+++ b/test/unit/api/ingest/_simulate.js
@@ -1,8 +1,8 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let createTestData = require('intern/dojo/node!../../../unit/api/ingest/data');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const createTestData = require('intern/dojo/node!../../../unit/api/ingest/data');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/index.js b/test/unit/api/ingest/index.js
index e0a40193c94b2..27e45978a089b 100644
--- a/test/unit/api/ingest/index.js
+++ b/test/unit/api/ingest/index.js
@@ -1,20 +1,20 @@
 define(function (require) {
-  let bdd = require('intern!bdd');
-  let serverConfig = require('intern/dojo/node!../../../server_config');
-  let ScenarioManager = require('intern/dojo/node!../../../fixtures/scenario_manager');
+  const bdd = require('intern!bdd');
+  const serverConfig = require('intern/dojo/node!../../../server_config');
+  const ScenarioManager = require('intern/dojo/node!../../../fixtures/scenario_manager');
   let request = require('intern/dojo/node!supertest-as-promised');
-  let url = require('intern/dojo/node!url');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
-  let post = require('./_post');
-  let del = require('./_del');
-  let data = require('./_data');
-  let simulate = require('./_simulate');
-  let processors = require('./_processors');
-  let processorTypes = require('./processors/index');
+  const url = require('intern/dojo/node!url');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
+  const post = require('./_post');
+  const del = require('./_del');
+  const data = require('./_data');
+  const simulate = require('./_simulate');
+  const processors = require('./_processors');
+  const processorTypes = require('./processors/index');
 
   bdd.describe('ingest API', function () {
-    let scenarioManager = new ScenarioManager(url.format(serverConfig.servers.elasticsearch));
+    const scenarioManager = new ScenarioManager(url.format(serverConfig.servers.elasticsearch));
     request = request(url.format(serverConfig.servers.kibana) + '/api');
 
     bdd.before(function () {
diff --git a/test/unit/api/ingest/processors/_append.js b/test/unit/api/ingest/processors/_append.js
index 7fc214870d7a9..5dab023e0a5ff 100644
--- a/test/unit/api/ingest/processors/_append.js
+++ b/test/unit/api/ingest/processors/_append.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_convert.js b/test/unit/api/ingest/processors/_convert.js
index f96a936081f2b..22a03b5b80909 100644
--- a/test/unit/api/ingest/processors/_convert.js
+++ b/test/unit/api/ingest/processors/_convert.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_date.js b/test/unit/api/ingest/processors/_date.js
index df21a8ef07383..7c233a52d0175 100644
--- a/test/unit/api/ingest/processors/_date.js
+++ b/test/unit/api/ingest/processors/_date.js
@@ -1,8 +1,8 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
-  let moment = require('intern/dojo/node!moment');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
+  const moment = require('intern/dojo/node!moment');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_geoip.js b/test/unit/api/ingest/processors/_geoip.js
index 9131a143c6d9f..4cb9f78a210d1 100644
--- a/test/unit/api/ingest/processors/_geoip.js
+++ b/test/unit/api/ingest/processors/_geoip.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_grok.js b/test/unit/api/ingest/processors/_grok.js
index ffb9584e3a706..f2875295a03c8 100644
--- a/test/unit/api/ingest/processors/_grok.js
+++ b/test/unit/api/ingest/processors/_grok.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_gsub.js b/test/unit/api/ingest/processors/_gsub.js
index cd9afe53b2004..818a49660207a 100644
--- a/test/unit/api/ingest/processors/_gsub.js
+++ b/test/unit/api/ingest/processors/_gsub.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_join.js b/test/unit/api/ingest/processors/_join.js
index 18f9896b291ba..26843db43fa8f 100644
--- a/test/unit/api/ingest/processors/_join.js
+++ b/test/unit/api/ingest/processors/_join.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_lowercase.js b/test/unit/api/ingest/processors/_lowercase.js
index df5c0b206afff..b843d70d67bd1 100644
--- a/test/unit/api/ingest/processors/_lowercase.js
+++ b/test/unit/api/ingest/processors/_lowercase.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_remove.js b/test/unit/api/ingest/processors/_remove.js
index 6c08025f4457c..a891cf9a12ccb 100644
--- a/test/unit/api/ingest/processors/_remove.js
+++ b/test/unit/api/ingest/processors/_remove.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_rename.js b/test/unit/api/ingest/processors/_rename.js
index a11249eb74c38..ea28f87b83092 100644
--- a/test/unit/api/ingest/processors/_rename.js
+++ b/test/unit/api/ingest/processors/_rename.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_set.js b/test/unit/api/ingest/processors/_set.js
index 9f247ae044fa7..9f544b799ffcf 100644
--- a/test/unit/api/ingest/processors/_set.js
+++ b/test/unit/api/ingest/processors/_set.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_split.js b/test/unit/api/ingest/processors/_split.js
index df0473f016a31..802b844c2f250 100644
--- a/test/unit/api/ingest/processors/_split.js
+++ b/test/unit/api/ingest/processors/_split.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_trim.js b/test/unit/api/ingest/processors/_trim.js
index da33e3d3be840..76a00f9dd940d 100644
--- a/test/unit/api/ingest/processors/_trim.js
+++ b/test/unit/api/ingest/processors/_trim.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/_uppercase.js b/test/unit/api/ingest/processors/_uppercase.js
index 751e695526a57..bba03ebbc9f34 100644
--- a/test/unit/api/ingest/processors/_uppercase.js
+++ b/test/unit/api/ingest/processors/_uppercase.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   const testPipeline = {
     processors: [{
diff --git a/test/unit/api/ingest/processors/index.js b/test/unit/api/ingest/processors/index.js
index b5d25061c25b8..8ede084d2cd78 100644
--- a/test/unit/api/ingest/processors/index.js
+++ b/test/unit/api/ingest/processors/index.js
@@ -1,18 +1,18 @@
 define(function (require) {
-  let append = require('./_append');
-  let convert = require('./_convert');
-  let date = require('./_date');
-  let geoip = require('./_geoip');
-  let grok = require('./_grok');
-  let gsub = require('./_gsub');
-  let join = require('./_join');
-  let lowercase = require('./_lowercase');
-  let remove = require('./_remove');
-  let rename = require('./_rename');
-  let set = require('./_set');
-  let split = require('./_split');
-  let trim = require('./_trim');
-  let uppercase = require('./_uppercase');
+  const append = require('./_append');
+  const convert = require('./_convert');
+  const date = require('./_date');
+  const geoip = require('./_geoip');
+  const grok = require('./_grok');
+  const gsub = require('./_gsub');
+  const join = require('./_join');
+  const lowercase = require('./_lowercase');
+  const remove = require('./_remove');
+  const rename = require('./_rename');
+  const set = require('./_set');
+  const split = require('./_split');
+  const trim = require('./_trim');
+  const uppercase = require('./_uppercase');
 
   return function processors(bdd, scenarioManager, request) {
     append(bdd, scenarioManager, request);
diff --git a/test/unit/api/search/_count.js b/test/unit/api/search/_count.js
index 235f0b9002358..f7a1dc8327a4b 100644
--- a/test/unit/api/search/_count.js
+++ b/test/unit/api/search/_count.js
@@ -1,7 +1,7 @@
 define(function (require) {
-  let Promise = require('bluebird');
-  let _ = require('intern/dojo/node!lodash');
-  let expect = require('intern/dojo/node!expect.js');
+  const Promise = require('bluebird');
+  const _ = require('intern/dojo/node!lodash');
+  const expect = require('intern/dojo/node!expect.js');
 
   return function (bdd, scenarioManager, request) {
     bdd.describe('Count API', function postIngest() {
diff --git a/test/unit/api/search/index.js b/test/unit/api/search/index.js
index 111f6d837bf92..8639f605e6b44 100644
--- a/test/unit/api/search/index.js
+++ b/test/unit/api/search/index.js
@@ -1,13 +1,13 @@
 define(function (require) {
-  let bdd = require('intern!bdd');
-  let serverConfig = require('intern/dojo/node!../../../server_config');
-  let ScenarioManager = require('intern/dojo/node!../../../fixtures/scenario_manager');
+  const bdd = require('intern!bdd');
+  const serverConfig = require('intern/dojo/node!../../../server_config');
+  const ScenarioManager = require('intern/dojo/node!../../../fixtures/scenario_manager');
   let request = require('intern/dojo/node!supertest-as-promised');
-  let url = require('intern/dojo/node!url');
-  let count = require('./_count');
+  const url = require('intern/dojo/node!url');
+  const count = require('./_count');
 
   bdd.describe('search API', function () {
-    let scenarioManager = new ScenarioManager(url.format(serverConfig.servers.elasticsearch));
+    const scenarioManager = new ScenarioManager(url.format(serverConfig.servers.elasticsearch));
     request = request(url.format(serverConfig.servers.kibana) + '/api');
 
     bdd.before(function () {
diff --git a/test/utils/__tests__/get_page.js b/test/utils/__tests__/get_page.js
index ac61ad2760ff3..3b10903b3c301 100644
--- a/test/utils/__tests__/get_page.js
+++ b/test/utils/__tests__/get_page.js
@@ -1,9 +1,9 @@
-let expect = require('expect.js');
-let getUrl = require('../get_url');
+const expect = require('expect.js');
+const getUrl = require('../get_url');
 
 describe('getUrl', function () {
   it('should convert to a url', function () {
-    let url = getUrl({
+    const url = getUrl({
       protocol: 'http',
       hostname: 'localhost',
     }, {
@@ -14,7 +14,7 @@ describe('getUrl', function () {
   });
 
   it('should convert to a url with port', function () {
-    let url = getUrl({
+    const url = getUrl({
       protocol: 'http',
       hostname: 'localhost',
       port: 9220
diff --git a/test/utils/get_url.js b/test/utils/get_url.js
index cff9f6c5cb6a1..1bbcbf0ecfc53 100644
--- a/test/utils/get_url.js
+++ b/test/utils/get_url.js
@@ -1,5 +1,5 @@
-let _ = require('lodash');
-let url = require('url');
+const _ = require('lodash');
+const url = require('url');
 
 /**
 * Converts a config and a pathname to a url
diff --git a/test/visual_regression/home/_loading.js b/test/visual_regression/home/_loading.js
index 97aa0b81088ff..ac53a6b59a965 100644
--- a/test/visual_regression/home/_loading.js
+++ b/test/visual_regression/home/_loading.js
@@ -5,7 +5,7 @@ import {
   consolePage
 } from '../../support';
 
-let expect = require('expect.js');
+const expect = require('expect.js');
 
 bdd.describe('Loading', function coverLoadingUi() {
   bdd.it('should show loading feebdack', async function () {