From d81e7330a4a4d02163b12ae07cd5d938140f6741 Mon Sep 17 00:00:00 2001
From: joe fleming <joe.fleming@gmail.com>
Date: Tue, 19 Mar 2019 16:50:25 -0700
Subject: [PATCH 1/3] test: add more filter elements

---
 .../state/selectors/__tests__/workpad.js      | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js b/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js
index 5cfdf726dd258..622006234b66e 100644
--- a/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js
+++ b/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js
@@ -33,6 +33,39 @@ describe('workpad selectors', () => {
           },
         ],
       },
+      'element-3': {
+        type: 'expression',
+        chain: [
+          {
+            type: 'function',
+            function: 'demodata',
+            arguments: {},
+          },
+          {
+            type: 'function',
+            function: 'dropdownControl',
+            arguments: {
+              valueColumn: ['project'],
+              filterColumn: ['project'],
+            },
+          },
+          {
+            type: 'function',
+            function: 'render',
+            arguments: {},
+          },
+        ],
+      },
+      'element-4': {
+        type: 'expression',
+        chain: [
+          {
+            type: 'function',
+            function: 'timefilterControl',
+            arguments: { compact: [true], column: ['@timestamp'] },
+          },
+        ],
+      },
     };
 
     state = {
@@ -63,10 +96,23 @@ describe('workpad selectors', () => {
                 {
                   id: 'element-0',
                   expression: 'markdown',
+                  filter: '',
                 },
                 {
                   id: 'element-1',
                   expression: 'demodata',
+                  filter: '',
+                },
+                {
+                  id: 'element-3',
+                  expression:
+                    'demodata | dropdownControl valueColumn=project filterColumn=project | render',
+                  filter: 'exactly value="beats" column="project"',
+                },
+                {
+                  id: 'element-4',
+                  expression: 'timefilterControl compact=true column=@timestamp',
+                  filter: 'timefilter column=@timestamp from=now-24h to=now',
                 },
               ],
             },
@@ -135,6 +181,7 @@ describe('workpad selectors', () => {
 
     it('returns all elements on the page', () => {
       const { elements } = state.persistent.workpad.pages[0];
+
       const expected = elements.map(element => ({
         ...element,
         ast: asts[element.id],

From 5c7c958d500a10106ba7e79633a2f5051cf5b895 Mon Sep 17 00:00:00 2001
From: joe fleming <joe.fleming@gmail.com>
Date: Tue, 19 Mar 2019 16:58:11 -0700
Subject: [PATCH 2/3] test: add getGlobalFilterExpression test

---
 .../canvas/public/state/selectors/__tests__/workpad.js   | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js b/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js
index 622006234b66e..bd56e1cd6e1d2 100644
--- a/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js
+++ b/x-pack/plugins/canvas/public/state/selectors/__tests__/workpad.js
@@ -245,6 +245,15 @@ describe('workpad selectors', () => {
     });
   });
 
+  describe('getGlobalFilterExpression', () => {
+    it('gets filters from all elements', () => {
+      const filters = selector.getGlobalFilterExpression(state);
+      expect(filters).to.equal(
+        'exactly value="beats" column="project" | timefilter column=@timestamp from=now-24h to=now'
+      );
+    });
+  });
+
   describe('isWriteable', () => {
     it('returns boolean for if the workpad is writeable', () => {
       expect(selector.isWriteable(state)).to.equal(false);

From 7fb2fcb65e3803434282315829629f7849ba7668 Mon Sep 17 00:00:00 2001
From: joe fleming <joe.fleming@gmail.com>
Date: Tue, 19 Mar 2019 17:06:44 -0700
Subject: [PATCH 3/3] chore: only iterate filter elements once

---
 .../plugins/canvas/public/state/selectors/workpad.js   | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/x-pack/plugins/canvas/public/state/selectors/workpad.js b/x-pack/plugins/canvas/public/state/selectors/workpad.js
index 66e82f0cbab86..103bed6e52831 100644
--- a/x-pack/plugins/canvas/public/state/selectors/workpad.js
+++ b/x-pack/plugins/canvas/public/state/selectors/workpad.js
@@ -116,8 +116,14 @@ export function getElementStats(state) {
 
 export function getGlobalFilterExpression(state) {
   return getAllElements(state)
-    .map(el => el.filter)
-    .filter(str => str != null && str.length)
+    .reduce((acc, el) => {
+      // check that a filter is defined
+      if (el.filter != null && el.filter.length) {
+        return acc.concat(el.filter);
+      }
+
+      return acc;
+    }, [])
     .join(' | ');
 }