diff --git a/RNTester/js/LayoutEventsExample.js b/RNTester/js/LayoutEventsExample.js
index c921f90087457c..e0676af568b31e 100644
--- a/RNTester/js/LayoutEventsExample.js
+++ b/RNTester/js/LayoutEventsExample.js
@@ -10,9 +10,9 @@
 
 'use strict';
 
-var React = require('react');
-var ReactNative = require('react-native');
-var {Image, LayoutAnimation, StyleSheet, Text, View} = ReactNative;
+const React = require('react');
+const ReactNative = require('react-native');
+const {Image, LayoutAnimation, StyleSheet, Text, View} = ReactNative;
 
 import type {ViewLayout, ViewLayoutEvent} from 'ViewPropTypes';
 
@@ -71,9 +71,9 @@ class LayoutEventExample extends React.Component<{}, State> {
   };
 
   render() {
-    var viewStyle = [styles.view, this.state.viewStyle];
-    var textLayout = this.state.textLayout || {width: '?', height: '?'};
-    var imageLayout = this.state.imageLayout || {x: '?', y: '?'};
+    const viewStyle = [styles.view, this.state.viewStyle];
+    const textLayout = this.state.textLayout || {width: '?', height: '?'};
+    const imageLayout = this.state.imageLayout || {x: '?', y: '?'};
     return (
       <View style={this.state.containerStyle}>
         <Text>
@@ -113,7 +113,7 @@ class LayoutEventExample extends React.Component<{}, State> {
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   view: {
     padding: 12,
     borderColor: 'black',
diff --git a/RNTester/js/LayoutExample.js b/RNTester/js/LayoutExample.js
index 9b32ec60c4443e..fed6f705783acd 100644
--- a/RNTester/js/LayoutExample.js
+++ b/RNTester/js/LayoutExample.js
@@ -10,17 +10,17 @@
 
 'use strict';
 
-var React = require('react');
-var ReactNative = require('react-native');
-var {StyleSheet, Text, View} = ReactNative;
+const React = require('react');
+const ReactNative = require('react-native');
+const {StyleSheet, Text, View} = ReactNative;
 
-var RNTesterBlock = require('./RNTesterBlock');
-var RNTesterPage = require('./RNTesterPage');
+const RNTesterBlock = require('./RNTesterBlock');
+const RNTesterPage = require('./RNTesterPage');
 
 class Circle extends React.Component<$FlowFixMeProps> {
   render() {
-    var size = this.props.size || 20;
-    var backgroundColor = this.props.bgColor || '#527fe4';
+    const size = this.props.size || 20;
+    const backgroundColor = this.props.bgColor || '#527fe4';
     return (
       <View
         style={{
@@ -37,7 +37,7 @@ class Circle extends React.Component<$FlowFixMeProps> {
 
 class CircleBlock extends React.Component<$FlowFixMeProps> {
   render() {
-    var circleStyle = {
+    const circleStyle = {
       flexDirection: 'row',
       backgroundColor: '#f6f7f8',
       borderWidth: 0.5,
@@ -56,7 +56,7 @@ class LayoutExample extends React.Component<$FlowFixMeProps> {
   static displayName = 'LayoutExample';
 
   render() {
-    var fiveColoredCircles = [
+    const fiveColoredCircles = [
       <Circle bgColor="#527fe4" key="blue" />,
       <Circle bgColor="#D443E3" key="violet" />,
       <Circle bgColor="#FF9049" key="orange" />,
@@ -186,7 +186,7 @@ class LayoutExample extends React.Component<$FlowFixMeProps> {
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   overlay: {
     backgroundColor: '#aaccff',
     borderRadius: 10,
diff --git a/RNTester/js/ListViewExample.js b/RNTester/js/ListViewExample.js
index f52f3dfb461af1..eb2c572be2844c 100644
--- a/RNTester/js/ListViewExample.js
+++ b/RNTester/js/ListViewExample.js
@@ -69,8 +69,8 @@ class ListViewSimpleExample extends React.Component<RNTesterProps, State> {
     rowID: number,
     highlightRow: (sectionID: number, rowID: number) => void,
   ) => {
-    var rowHash = Math.abs(hashCode(rowData));
-    var imgSource = THUMB_URLS[rowHash % THUMB_URLS.length];
+    const rowHash = Math.abs(hashCode(rowData));
+    const imgSource = THUMB_URLS[rowHash % THUMB_URLS.length];
     return (
       <TouchableHighlight
         onPress={() => {
@@ -90,9 +90,9 @@ class ListViewSimpleExample extends React.Component<RNTesterProps, State> {
   };
 
   _genRows(pressData: {[key: number]: boolean}): Array<string> {
-    var dataBlob = [];
-    for (var ii = 0; ii < 100; ii++) {
-      var pressedText = pressData[ii] ? ' (pressed)' : '';
+    const dataBlob = [];
+    for (let ii = 0; ii < 100; ii++) {
+      const pressedText = pressData[ii] ? ' (pressed)' : '';
       dataBlob.push('Row ' + ii + pressedText);
     }
     return dataBlob;
@@ -124,7 +124,7 @@ class ListViewSimpleExample extends React.Component<RNTesterProps, State> {
   }
 }
 
-var THUMB_URLS = [
+const THUMB_URLS = [
   require('./Thumbnails/like.png'),
   require('./Thumbnails/dislike.png'),
   require('./Thumbnails/call.png'),
@@ -138,19 +138,19 @@ var THUMB_URLS = [
   require('./Thumbnails/superlike.png'),
   require('./Thumbnails/victory.png'),
 ];
-var LOREM_IPSUM =
+const LOREM_IPSUM =
   'Lorem ipsum dolor sit amet, ius ad pertinax oportere accommodare, an vix civibus corrumpit referrentur. Te nam case ludus inciderint, te mea facilisi adipiscing. Sea id integre luptatum. In tota sale consequuntur nec. Erat ocurreret mei ei. Eu paulo sapientem vulputate est, vel an accusam intellegam interesset. Nam eu stet pericula reprimique, ea vim illud modus, putant invidunt reprehendunt ne qui.';
 
 /* eslint no-bitwise: 0 */
-var hashCode = function(str) {
-  var hash = 15;
-  for (var ii = str.length - 1; ii >= 0; ii--) {
+const hashCode = function(str) {
+  let hash = 15;
+  for (let ii = str.length - 1; ii >= 0; ii--) {
     hash = (hash << 5) - hash + str.charCodeAt(ii);
   }
   return hash;
 };
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   row: {
     flexDirection: 'row',
     justifyContent: 'center',
diff --git a/RNTester/js/ListViewGridLayoutExample.js b/RNTester/js/ListViewGridLayoutExample.js
index 2f3340d151af5d..2bc2cb2514389a 100644
--- a/RNTester/js/ListViewGridLayoutExample.js
+++ b/RNTester/js/ListViewGridLayoutExample.js
@@ -24,7 +24,7 @@ const ListViewDataSource = require('ListViewDataSource');
 
 import type {RNTesterProps} from 'RNTesterTypes';
 
-var THUMB_URLS = [
+const THUMB_URLS = [
   require('./Thumbnails/like.png'),
   require('./Thumbnails/dislike.png'),
   require('./Thumbnails/call.png'),
@@ -78,8 +78,8 @@ class ListViewGridLayoutExample extends React.Component<RNTesterProps, State> {
   }
 
   _renderRow = (rowData: string, sectionID: number, rowID: number) => {
-    var rowHash = Math.abs(hashCode(rowData));
-    var imgSource = THUMB_URLS[rowHash % THUMB_URLS.length];
+    const rowHash = Math.abs(hashCode(rowData));
+    const imgSource = THUMB_URLS[rowHash % THUMB_URLS.length];
     return (
       <TouchableHighlight
         onPress={() => this._pressRow(rowID)}
@@ -95,9 +95,9 @@ class ListViewGridLayoutExample extends React.Component<RNTesterProps, State> {
   };
 
   _genRows(pressData: {[key: number]: boolean}): Array<string> {
-    var dataBlob = [];
-    for (var ii = 0; ii < 100; ii++) {
-      var pressedText = pressData[ii] ? ' (X)' : '';
+    const dataBlob = [];
+    for (let ii = 0; ii < 100; ii++) {
+      const pressedText = pressData[ii] ? ' (X)' : '';
       dataBlob.push('Cell ' + ii + pressedText);
     }
     return dataBlob;
@@ -114,15 +114,15 @@ class ListViewGridLayoutExample extends React.Component<RNTesterProps, State> {
 }
 
 /* eslint no-bitwise: 0 */
-var hashCode = function(str) {
-  var hash = 15;
-  for (var ii = str.length - 1; ii >= 0; ii--) {
+const hashCode = function(str) {
+  let hash = 15;
+  for (let ii = str.length - 1; ii >= 0; ii--) {
     hash = (hash << 5) - hash + str.charCodeAt(ii);
   }
   return hash;
 };
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   list: {
     justifyContent: 'space-around',
     flexDirection: 'row',
diff --git a/RNTester/js/ListViewPagingExample.js b/RNTester/js/ListViewPagingExample.js
index 85598c2ae5fb75..a19e3afd040f66 100644
--- a/RNTester/js/ListViewPagingExample.js
+++ b/RNTester/js/ListViewPagingExample.js
@@ -10,9 +10,9 @@
 
 'use strict';
 
-var React = require('react');
-var ReactNative = require('react-native');
-var {
+const React = require('react');
+const ReactNative = require('react-native');
+const {
   Image,
   LayoutAnimation,
   ListView,
@@ -22,10 +22,10 @@ var {
   View,
 } = ReactNative;
 
-var NativeModules = require('NativeModules');
-var {UIManager} = NativeModules;
+const NativeModules = require('NativeModules');
+const {UIManager} = NativeModules;
 
-var THUMB_URLS = [
+const THUMB_URLS = [
   require('./Thumbnails/like.png'),
   require('./Thumbnails/dislike.png'),
   require('./Thumbnails/call.png'),
@@ -39,8 +39,8 @@ var THUMB_URLS = [
   require('./Thumbnails/superlike.png'),
   require('./Thumbnails/victory.png'),
 ];
-var NUM_SECTIONS = 100;
-var NUM_ROWS_PER_SECTION = 10;
+const NUM_SECTIONS = 100;
+const NUM_ROWS_PER_SECTION = 10;
 
 class Thumb extends React.Component<{}, $FlowFixMeState> {
   UNSAFE_componentWillMount() {
@@ -53,7 +53,7 @@ class Thumb extends React.Component<{}, $FlowFixMeState> {
   };
 
   _onPressThumb = () => {
-    var config =
+    const config =
       layoutAnimationConfigs[
         this.state.thumbIndex % layoutAnimationConfigs.length
       ];
@@ -94,31 +94,31 @@ class ListViewPagingExample extends React.Component<$FlowFixMeProps, *> {
   // $FlowFixMe found when converting React.createClass to ES6
   constructor(props) {
     super(props);
-    var getSectionData = (dataBlob, sectionID) => {
+    const getSectionData = (dataBlob, sectionID) => {
       return dataBlob[sectionID];
     };
-    var getRowData = (dataBlob, sectionID, rowID) => {
+    const getRowData = (dataBlob, sectionID, rowID) => {
       return dataBlob[rowID];
     };
 
-    var dataSource = new ListView.DataSource({
+    const dataSource = new ListView.DataSource({
       getRowData: getRowData,
       getSectionHeaderData: getSectionData,
       rowHasChanged: (row1, row2) => row1 !== row2,
       sectionHeaderHasChanged: (s1, s2) => s1 !== s2,
     });
 
-    var dataBlob = {};
-    var sectionIDs = [];
-    var rowIDs = [];
-    for (var ii = 0; ii < NUM_SECTIONS; ii++) {
-      var sectionName = 'Section ' + ii;
+    const dataBlob = {};
+    const sectionIDs = [];
+    const rowIDs = [];
+    for (let ii = 0; ii < NUM_SECTIONS; ii++) {
+      const sectionName = 'Section ' + ii;
       sectionIDs.push(sectionName);
       dataBlob[sectionName] = sectionName;
       rowIDs[ii] = [];
 
-      for (var jj = 0; jj < NUM_ROWS_PER_SECTION; jj++) {
-        var rowName = 'S' + ii + ', R' + jj;
+      for (let jj = 0; jj < NUM_ROWS_PER_SECTION; jj++) {
+        const rowName = 'S' + ii + ', R' + jj;
         rowIDs[ii].push(rowName);
         dataBlob[rowName] = rowName;
       }
@@ -151,7 +151,7 @@ class ListViewPagingExample extends React.Component<$FlowFixMeProps, *> {
   };
 
   renderHeader = () => {
-    var headerLikeText =
+    const headerLikeText =
       this.state.headerPressCount % 2 ? (
         <View>
           <Text style={styles.text}>1 Like</Text>
@@ -198,7 +198,7 @@ class ListViewPagingExample extends React.Component<$FlowFixMeProps, *> {
   }
 
   _onPressHeader = () => {
-    var config =
+    const config =
       layoutAnimationConfigs[
         Math.floor(this.state.headerPressCount / 2) %
           layoutAnimationConfigs.length
@@ -208,7 +208,7 @@ class ListViewPagingExample extends React.Component<$FlowFixMeProps, *> {
   };
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   listview: {
     backgroundColor: '#B0C4DE',
   },
@@ -256,7 +256,7 @@ var styles = StyleSheet.create({
   },
 });
 
-var animations = {
+const animations = {
   layout: {
     spring: {
       duration: 750,
@@ -284,7 +284,7 @@ var animations = {
   },
 };
 
-var layoutAnimationConfigs = [
+const layoutAnimationConfigs = [
   animations.layout.spring,
   animations.layout.easeInEaseOut,
 ];
diff --git a/RNTester/js/ModalExample.js b/RNTester/js/ModalExample.js
index 34025634360242..e8a306b17aba27 100644
--- a/RNTester/js/ModalExample.js
+++ b/RNTester/js/ModalExample.js
@@ -10,9 +10,9 @@
 
 'use strict';
 
-var React = require('react');
-var ReactNative = require('react-native');
-var {
+const React = require('react');
+const ReactNative = require('react-native');
+const {
   Modal,
   Picker,
   Platform,
@@ -44,7 +44,7 @@ class Button extends React.Component<$FlowFixMeProps, $FlowFixMeState> {
   };
 
   render() {
-    var colorStyle = {
+    const colorStyle = {
       color: this.state.active ? '#fff' : '#000',
     };
     return (
@@ -106,15 +106,15 @@ class ModalExample extends React.Component<{}, $FlowFixMeState> {
   }
 
   render() {
-    var modalBackgroundStyle = {
+    const modalBackgroundStyle = {
       backgroundColor: this.state.transparent
         ? 'rgba(0, 0, 0, 0.5)'
         : '#f5fcff',
     };
-    var innerContainerTransparentStyle = this.state.transparent
+    const innerContainerTransparentStyle = this.state.transparent
       ? {backgroundColor: '#fff', padding: 20}
       : null;
-    var activeButtonStyle = {
+    const activeButtonStyle = {
       backgroundColor: '#ddd',
     };
 
@@ -241,7 +241,7 @@ exports.examples = [
   },
 ];
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   container: {
     flex: 1,
     justifyContent: 'center',
diff --git a/RNTester/js/NativeAnimationsExample.js b/RNTester/js/NativeAnimationsExample.js
index 4c5a094033a4e5..176e668f52d44f 100644
--- a/RNTester/js/NativeAnimationsExample.js
+++ b/RNTester/js/NativeAnimationsExample.js
@@ -21,7 +21,7 @@ const {
   Slider,
 } = ReactNative;
 
-var AnimatedSlider = Animated.createAnimatedComponent(Slider);
+const AnimatedSlider = Animated.createAnimatedComponent(Slider);
 
 class Tester extends React.Component<$FlowFixMeProps, $FlowFixMeState> {
   state = {
diff --git a/RNTester/js/PanResponderExample.js b/RNTester/js/PanResponderExample.js
index 82e0ecf0134ee5..b484dc086bfb52 100644
--- a/RNTester/js/PanResponderExample.js
+++ b/RNTester/js/PanResponderExample.js
@@ -126,7 +126,7 @@ class PanResponderExample extends React.Component<Props> {
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   circle: {
     width: CIRCLE_SIZE,
     height: CIRCLE_SIZE,
diff --git a/RNTester/js/PermissionsExampleAndroid.android.js b/RNTester/js/PermissionsExampleAndroid.android.js
index b58251d9aef13d..285b2827f31fdd 100644
--- a/RNTester/js/PermissionsExampleAndroid.android.js
+++ b/RNTester/js/PermissionsExampleAndroid.android.js
@@ -114,7 +114,7 @@ exports.examples = [
   },
 ];
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   container: {
     flex: 1,
     backgroundColor: 'white',
diff --git a/RNTester/js/PickerExample.js b/RNTester/js/PickerExample.js
index f4bfe5f23b61fe..ad234e5ebe8bad 100644
--- a/RNTester/js/PickerExample.js
+++ b/RNTester/js/PickerExample.js
@@ -123,7 +123,7 @@ class PickerExample extends React.Component<{}, $FlowFixMeState> {
   };
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   picker: {
     width: 100,
   },
diff --git a/RNTester/js/PickerIOSExample.js b/RNTester/js/PickerIOSExample.js
index 0965e29f1b04ed..4023834242e72f 100644
--- a/RNTester/js/PickerIOSExample.js
+++ b/RNTester/js/PickerIOSExample.js
@@ -10,13 +10,13 @@
 
 'use strict';
 
-var React = require('react');
-var ReactNative = require('react-native');
-var {PickerIOS, Text, View} = ReactNative;
+const React = require('react');
+const ReactNative = require('react-native');
+const {PickerIOS, Text, View} = ReactNative;
 
-var PickerItemIOS = PickerIOS.Item;
+const PickerItemIOS = PickerIOS.Item;
 
-var CAR_MAKES_AND_MODELS = {
+const CAR_MAKES_AND_MODELS = {
   amc: {
     name: 'AMC',
     models: ['AMX', 'Concord', 'Eagle', 'Gremlin', 'Matador', 'Pacer'],
@@ -105,8 +105,9 @@ class PickerExample extends React.Component<{}, $FlowFixMeState> {
   };
 
   render() {
-    var make = CAR_MAKES_AND_MODELS[this.state.carMake];
-    var selectionString = make.name + ' ' + make.models[this.state.modelIndex];
+    const make = CAR_MAKES_AND_MODELS[this.state.carMake];
+    const selectionString =
+      make.name + ' ' + make.models[this.state.modelIndex];
     return (
       <View>
         <Text>Please choose a make for your car:</Text>
diff --git a/RNTester/js/PointerEventsExample.js b/RNTester/js/PointerEventsExample.js
index ddc9a9cf0ccf8b..73552838d1527d 100644
--- a/RNTester/js/PointerEventsExample.js
+++ b/RNTester/js/PointerEventsExample.js
@@ -10,9 +10,9 @@
 
 'use strict';
 
-var React = require('react');
-var ReactNative = require('react-native');
-var {StyleSheet, Text, View} = ReactNative;
+const React = require('react');
+const ReactNative = require('react-native');
+const {StyleSheet, Text, View} = ReactNative;
 
 class ExampleBox extends React.Component<$FlowFixMeProps, $FlowFixMeState> {
   state = {
@@ -171,7 +171,7 @@ type ExampleClass = {
   description: string,
 };
 
-var exampleClasses: Array<ExampleClass> = [
+const exampleClasses: Array<ExampleClass> = [
   {
     Component: NoneExample,
     title: '`none`',
@@ -192,7 +192,7 @@ var exampleClasses: Array<ExampleClass> = [
   },
 ];
 
-var infoToExample = info => {
+const infoToExample = info => {
   return {
     title: info.title,
     description: info.description,
@@ -202,7 +202,7 @@ var infoToExample = info => {
   };
 };
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   text: {
     fontSize: 10,
     color: '#5577cc',
diff --git a/RNTester/js/ProgressBarAndroidExample.android.js b/RNTester/js/ProgressBarAndroidExample.android.js
index 81c0a4554253ad..c806a4c6c331cb 100644
--- a/RNTester/js/ProgressBarAndroidExample.android.js
+++ b/RNTester/js/ProgressBarAndroidExample.android.js
@@ -10,13 +10,13 @@
 
 'use strict';
 
-var ProgressBar = require('ProgressBarAndroid');
-var React = require('React');
-var createReactClass = require('create-react-class');
-var RNTesterBlock = require('RNTesterBlock');
-var RNTesterPage = require('RNTesterPage');
+const ProgressBar = require('ProgressBarAndroid');
+const React = require('React');
+const createReactClass = require('create-react-class');
+const RNTesterBlock = require('RNTesterBlock');
+const RNTesterPage = require('RNTesterPage');
 
-var MovingBar = createReactClass({
+const MovingBar = createReactClass({
   displayName: 'MovingBar',
   _intervalID: (null: ?IntervalID),
 
@@ -28,7 +28,7 @@ var MovingBar = createReactClass({
 
   componentDidMount: function() {
     this._intervalID = setInterval(() => {
-      var progress = (this.state.progress + 0.02) % 1;
+      const progress = (this.state.progress + 0.02) % 1;
       this.setState({progress: progress});
     }, 50);
   },
diff --git a/RNTester/js/ProgressViewIOSExample.js b/RNTester/js/ProgressViewIOSExample.js
index 7c6ebfe6c2a5ab..8f0c54dbc72d45 100644
--- a/RNTester/js/ProgressViewIOSExample.js
+++ b/RNTester/js/ProgressViewIOSExample.js
@@ -37,13 +37,13 @@ class ProgressViewExample extends React.Component<Props, State> {
   }
 
   updateProgress = () => {
-    var progress = this.state.progress + 0.01;
+    const progress = this.state.progress + 0.01;
     this.setState({progress});
     this._rafId = requestAnimationFrame(() => this.updateProgress());
   };
 
   getProgress = offset => {
-    var progress = this.state.progress + offset;
+    const progress = this.state.progress + offset;
     return Math.sin(progress % Math.PI) % 1;
   };
 
@@ -92,7 +92,7 @@ exports.examples = [
   },
 ];
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   container: {
     marginTop: -20,
     backgroundColor: 'transparent',
diff --git a/RNTester/js/PushNotificationIOSExample.js b/RNTester/js/PushNotificationIOSExample.js
index ba85c879488c6a..a841f126e7de95 100644
--- a/RNTester/js/PushNotificationIOSExample.js
+++ b/RNTester/js/PushNotificationIOSExample.js
@@ -10,9 +10,9 @@
 
 'use strict';
 
-var React = require('react');
-var ReactNative = require('react-native');
-var {
+const React = require('react');
+const ReactNative = require('react-native');
+const {
   AlertIOS,
   PushNotificationIOS,
   StyleSheet,
@@ -192,7 +192,7 @@ class NotificationPermissionExample extends React.Component<
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   button: {
     padding: 10,
     alignItems: 'center',