fix: onFocus/onBlur/onBeforeInput have a matching event type

packages/react-dom/src/events/DOMPluginEventSystem.js

@@ -709,7 +709,7 @@ export function accumulateSinglePhaseListeners(
 
   let instance = targetFiber;
   let lastHostComponent = null;
-  const targetType = event.type;
+  const targetType = event.nativeEvent.type;
 
   // Accumulate all instances and listeners via the target -> root path.
   while (instance !== null) {

packages/react-dom/src/events/ReactSyntheticEventType.js

@@ -29,6 +29,7 @@ export type ReactSyntheticEvent = {|
   _dispatchListeners?: null | Array<Function> | Function,
   _reactName: string,
   _targetInst: Fiber,
+  nativeEvent: Event,
   type: string,
   currentTarget: null | EventTarget,
 |};

packages/react-dom/src/events/SyntheticEvent.js

@@ -14,7 +14,6 @@ import getEventCharCode from './getEventCharCode';
  * @see http://www.w3.org/TR/DOM-Level-3-Events/
  */
 const EventInterface = {
-  type: 0,
   eventPhase: 0,
   bubbles: 0,
   cancelable: 0,
@@ -48,13 +47,15 @@ function functionThatReturnsFalse() {
  */
 export function SyntheticEvent(
   reactName,
+  reactEventType,
   targetInst,
   nativeEvent,
   nativeEventTarget,
   Interface = EventInterface,
 ) {
   this._reactName = reactName;
   this._targetInst = targetInst;
+  this.type = reactEventType;
   this.nativeEvent = nativeEvent;
   this.target = nativeEventTarget;
   this.currentTarget = null;

packages/react-dom/src/events/__tests__/SyntheticFocusEvent-test.js

@@ -0,0 +1,70 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+'use strict';
+
+describe('SyntheticFocusEvent', () => {
+  let React;
+  let ReactDOM;
+  let container;
+
+  beforeEach(() => {
+    jest.resetModules();
+    React = require('react');
+    ReactDOM = require('react-dom');
+
+    container = document.createElement('div');
+    document.body.appendChild(container);
+  });
+
+  afterEach(() => {
+    document.body.removeChild(container);
+    container = null;
+  });
+
+  test('onFocus events have the focus type', () => {
+    const log = [];
+    ReactDOM.render(
+      <button
+        onFocus={event => log.push(`onFocus: ${event.type}`)}
+        onFocusCapture={event => log.push(`onFocusCapture: ${event.type}`)}
+      />,
+      container,
+    );
+    const button = container.querySelector('button');
+
+    button.dispatchEvent(
+      new FocusEvent('focusin', {
+        bubbles: true,
+        cancelable: false,
+      }),
+    );
+
+    expect(log).toEqual(['onFocusCapture: focus', 'onFocus: focus']);
+  });
+
+  test('onBlur events have the blur type', () => {
+    const log = [];
+    ReactDOM.render(
+      <button
+        onBlur={event => log.push(`onBlur: ${event.type}`)}
+        onBlurCapture={event => log.push(`onBlurCapture: ${event.type}`)}
+      />,
+      container,
+    );
+    const button = container.querySelector('button');
+
+    button.dispatchEvent(
+      new FocusEvent('focusout', {
+        bubbles: true,
+        cancelable: false,
+      }),
+    );
+
+    expect(log).toEqual(['onBlurCapture: blur', 'onBlur: blur']);
+  });
+});

packages/react-dom/src/events/plugins/BeforeInputEventPlugin.js

@@ -229,6 +229,7 @@ function extractCompositionEvent(
 
   const event = new SyntheticEvent(
     eventType,
+    domEventName,
     null,
     nativeEvent,
     nativeEventTarget,
@@ -397,6 +398,7 @@ function extractBeforeInputEvent(
 
   const event = new SyntheticEvent(
     'onBeforeInput',
+    'beforeinput',
     null,
     nativeEvent,
     nativeEventTarget,

packages/react-dom/src/events/plugins/ChangeEventPlugin.js

@@ -49,8 +49,13 @@ function createAndAccumulateChangeEvent(
   nativeEvent,
   target,
 ) {
-  const event = new SyntheticEvent('onChange', null, nativeEvent, target);
-  event.type = 'change';
+  const event = new SyntheticEvent(
+    'onChange',
+    'change',
+    null,
+    nativeEvent,
+    target,
+  );
   // Flag this event loop as needing state restore.
   enqueueStateRestore(((target: any): Node));
   accumulateTwoPhaseListeners(inst, dispatchQueue, event);

packages/react-dom/src/events/plugins/EnterLeaveEventPlugin.js

@@ -133,23 +133,23 @@ function extractEvents(
 
   const leave = new SyntheticEvent(
     leaveEventType,
+    eventTypePrefix + 'leave',
     from,
     nativeEvent,
     nativeEventTarget,
     eventInterface,
   );
-  leave.type = eventTypePrefix + 'leave';
   leave.target = fromNode;
   leave.relatedTarget = toNode;
 
   let enter = new SyntheticEvent(
     enterEventType,
+    eventTypePrefix + 'enter',
     to,
     nativeEvent,
     nativeEventTarget,
     eventInterface,
   );
-  enter.type = eventTypePrefix + 'enter';
   enter.target = toNode;
   enter.relatedTarget = fromNode;
 

packages/react-dom/src/events/plugins/SelectEventPlugin.js

@@ -114,12 +114,11 @@ function constructSelectEvent(dispatchQueue, nativeEvent, nativeEventTarget) {
 
     const syntheticEvent = new SyntheticEvent(
       'onSelect',
+      'select',
       null,
       nativeEvent,
       nativeEventTarget,
     );
-
-    syntheticEvent.type = 'select';
     syntheticEvent.target = activeElement;
 
     accumulateTwoPhaseListeners(

packages/react-dom/src/events/plugins/SimpleEventPlugin.js

@@ -63,6 +63,7 @@ function extractEvents(
     return;
   }
   let EventInterface;
+  let reactEventType = domEventName;
   switch (domEventName) {
     case 'keypress':
       // Firefox creates a keypress event for function keys too. This removes
@@ -77,7 +78,13 @@ function extractEvents(
       EventInterface = KeyboardEventInterface;
       break;
     case 'focusin':
+      reactEventType = 'focus';
+      EventInterface = FocusEventInterface;
+      break;
     case 'focusout':
+      reactEventType = 'blur';
+      EventInterface = FocusEventInterface;
+      break;
     case 'beforeblur':
     case 'afterblur':
       EventInterface = FocusEventInterface;
@@ -152,6 +159,7 @@ function extractEvents(
   }
   const event = new SyntheticEvent(
     reactName,
+    reactEventType,
     null,
     nativeEvent,
     nativeEventTarget,