From 35d95239fad1d07d06c71e177f752da461741bcf Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Fri, 5 Jan 2018 17:21:33 +0000
Subject: [PATCH] Remove IE8 event.target polyfill via srcElement (#11515)

---
 .../__tests__/SyntheticClipboardEvent-test.js | 62 ----------------
 .../events/__tests__/SyntheticEvent-test.js   | 27 -------
 .../__tests__/SyntheticKeyboardEvent-test.js  | 70 -------------------
 .../__tests__/SyntheticWheelEvent-test.js     | 27 -------
 .../react-dom/src/events/getEventTarget.js    |  2 +-
 5 files changed, 1 insertion(+), 187 deletions(-)

diff --git a/packages/react-dom/src/events/__tests__/SyntheticClipboardEvent-test.js b/packages/react-dom/src/events/__tests__/SyntheticClipboardEvent-test.js
index 5213973ddd7fb..7be3695277aba 100644
--- a/packages/react-dom/src/events/__tests__/SyntheticClipboardEvent-test.js
+++ b/packages/react-dom/src/events/__tests__/SyntheticClipboardEvent-test.js
@@ -79,68 +79,6 @@ describe('SyntheticClipboardEvent', () => {
   });
 
   describe('EventInterface', () => {
-    it('normalizes properties from the Event interface', () => {
-      let expectedCount = 0;
-      let div;
-
-      const eventHandler = type => event => {
-        expect(event.target).toBe(div);
-        expect(event.type).toBe(type);
-        expectedCount++;
-      };
-
-      div = ReactDOM.render(
-        <div
-          onCopy={eventHandler('copy')}
-          onCut={eventHandler('cut')}
-          onPaste={eventHandler('paste')}
-        />,
-        container,
-      );
-
-      let event;
-      event = document.createEvent('Event');
-      event.initEvent('copy', true, true);
-      // Emulate IE8
-      Object.defineProperty(event, 'target', {
-        get() {},
-      });
-      Object.defineProperty(event, 'srcElement', {
-        get() {
-          return div;
-        },
-      });
-      div.dispatchEvent(event);
-
-      event = document.createEvent('Event');
-      event.initEvent('cut', true, true);
-      // Emulate IE8
-      Object.defineProperty(event, 'target', {
-        get() {},
-      });
-      Object.defineProperty(event, 'srcElement', {
-        get() {
-          return div;
-        },
-      });
-      div.dispatchEvent(event);
-
-      event = document.createEvent('Event');
-      event.initEvent('paste', true, true);
-      // Emulate IE8
-      Object.defineProperty(event, 'target', {
-        get() {},
-      });
-      Object.defineProperty(event, 'srcElement', {
-        get() {
-          return div;
-        },
-      });
-      div.dispatchEvent(event);
-
-      expect(expectedCount).toBe(3);
-    });
-
     it('is able to `preventDefault` and `stopPropagation`', () => {
       let expectedCount = 0;
 
diff --git a/packages/react-dom/src/events/__tests__/SyntheticEvent-test.js b/packages/react-dom/src/events/__tests__/SyntheticEvent-test.js
index 10420f1f9c7a0..c0609e5fe2234 100644
--- a/packages/react-dom/src/events/__tests__/SyntheticEvent-test.js
+++ b/packages/react-dom/src/events/__tests__/SyntheticEvent-test.js
@@ -30,33 +30,6 @@ describe('SyntheticEvent', () => {
     container = null;
   });
 
-  it('should normalize `target` from the nativeEvent', () => {
-    let node;
-    let expectedCount = 0;
-
-    const eventHandler = syntheticEvent => {
-      expect(syntheticEvent.target).toBe(node);
-
-      expectedCount++;
-    };
-    node = ReactDOM.render(<div onClick={eventHandler} />, container);
-
-    const event = document.createEvent('Event');
-    event.initEvent('click', true, true);
-    // Emulate IE8
-    Object.defineProperty(event, 'target', {
-      get() {},
-    });
-    Object.defineProperty(event, 'srcElement', {
-      get() {
-        return node;
-      },
-    });
-    node.dispatchEvent(event);
-
-    expect(expectedCount).toBe(1);
-  });
-
   it('should be able to `preventDefault`', () => {
     let node;
     let expectedCount = 0;
diff --git a/packages/react-dom/src/events/__tests__/SyntheticKeyboardEvent-test.js b/packages/react-dom/src/events/__tests__/SyntheticKeyboardEvent-test.js
index 16fd4d757e28b..4614f782ccc49 100644
--- a/packages/react-dom/src/events/__tests__/SyntheticKeyboardEvent-test.js
+++ b/packages/react-dom/src/events/__tests__/SyntheticKeyboardEvent-test.js
@@ -454,76 +454,6 @@ describe('SyntheticKeyboardEvent', () => {
   });
 
   describe('EventInterface', () => {
-    it('normalizes properties from the Event interface', () => {
-      let expectedCount = 0;
-      let div;
-      const eventHandler = type => event => {
-        expect(event.target).toBe(div);
-        expect(event.type).toBe(type);
-        expectedCount++;
-      };
-      div = ReactDOM.render(
-        <div
-          onKeyDown={eventHandler('keydown')}
-          onKeyPress={eventHandler('keypress')}
-          onKeyUp={eventHandler('keyup')}
-        />,
-        container,
-      );
-
-      let event;
-      event = new KeyboardEvent('keydown', {
-        keyCode: 40,
-        bubbles: true,
-        cancelable: true,
-      });
-      // Emulate IE8
-      Object.defineProperty(event, 'target', {
-        get() {},
-      });
-      Object.defineProperty(event, 'srcElement', {
-        get() {
-          return div;
-        },
-      });
-      div.dispatchEvent(event);
-
-      event = new KeyboardEvent('keyup', {
-        keyCode: 40,
-        bubbles: true,
-        cancelable: true,
-      });
-      // Emulate IE8
-      Object.defineProperty(event, 'target', {
-        get() {},
-      });
-      Object.defineProperty(event, 'srcElement', {
-        get() {
-          return div;
-        },
-      });
-      div.dispatchEvent(event);
-
-      event = new KeyboardEvent('keypress', {
-        charCode: 40,
-        keyCode: 40,
-        bubbles: true,
-        cancelable: true,
-      });
-      // Emulate IE8
-      Object.defineProperty(event, 'target', {
-        get() {},
-      });
-      Object.defineProperty(event, 'srcElement', {
-        get() {
-          return div;
-        },
-      });
-      div.dispatchEvent(event);
-
-      expect(expectedCount).toBe(3);
-    });
-
     it('is able to `preventDefault` and `stopPropagation`', () => {
       let expectedCount = 0;
       const eventHandler = event => {
diff --git a/packages/react-dom/src/events/__tests__/SyntheticWheelEvent-test.js b/packages/react-dom/src/events/__tests__/SyntheticWheelEvent-test.js
index 58979fbf9e7d8..0bcc32f4c1044 100644
--- a/packages/react-dom/src/events/__tests__/SyntheticWheelEvent-test.js
+++ b/packages/react-dom/src/events/__tests__/SyntheticWheelEvent-test.js
@@ -29,33 +29,6 @@ describe('SyntheticWheelEvent', () => {
     container = null;
   });
 
-  it('should normalize properties from the Event interface', () => {
-    const events = [];
-    const onWheel = event => {
-      event.persist();
-      events.push(event);
-    };
-    ReactDOM.render(<div onWheel={onWheel} />, container);
-
-    const event = new MouseEvent('wheel', {
-      bubbles: true,
-    });
-    // Emulate IE8
-    Object.defineProperty(event, 'target', {
-      get() {},
-    });
-    Object.defineProperty(event, 'srcElement', {
-      get() {
-        return container.firstChild;
-      },
-    });
-    container.firstChild.dispatchEvent(event);
-
-    expect(events.length).toBe(1);
-    expect(events[0].target).toBe(container.firstChild);
-    expect(events[0].type).toBe('wheel');
-  });
-
   it('should normalize properties from the MouseEvent interface', () => {
     const events = [];
     const onWheel = event => {
diff --git a/packages/react-dom/src/events/getEventTarget.js b/packages/react-dom/src/events/getEventTarget.js
index 028c184602477..76c0052c8520c 100644
--- a/packages/react-dom/src/events/getEventTarget.js
+++ b/packages/react-dom/src/events/getEventTarget.js
@@ -15,7 +15,7 @@ import {TEXT_NODE} from '../shared/HTMLNodeType';
  * @return {DOMEventTarget} Target node.
  */
 function getEventTarget(nativeEvent) {
-  let target = nativeEvent.target || nativeEvent.srcElement || window;
+  let target = nativeEvent.target || window;
 
   // Normalize SVG <use> element events #4963
   if (target.correspondingUseElement) {