Rename hover props in experimental event API and write unit tests

packages/react-events/src/Hover.js

@@ -29,19 +29,19 @@ if (typeof window !== 'undefined' && window.PointerEvent === undefined) {
   targetEventTypes.push('touchstart', 'mouseover', 'mouseout');
 }
 
-function dispatchHoverInEvents(
+function dispatchHoverStartEvents(
   context: EventResponderContext,
   props: Object,
   state: HoverState,
 ): void {
   const {event, eventTarget} = context;
+  if (context.isTargetWithinEventComponent((event: any).relatedTarget)) {
+    return;
+  }
+  if (props.onHoverStart) {
+    context.dispatchEvent('hoverstart', props.onHoverStart, eventTarget, true);
+  }
   if (props.onHoverChange) {
-    if (context.isTargetWithinEventComponent((event: any).relatedTarget)) {
-      return;
-    }
-    if (props.onHoverIn) {
-      context.dispatchEvent('hoverin', props.onHoverIn, eventTarget, true);
-    }
     const hoverChangeEventListener = () => {
       props.onHoverChange(true);
     };
@@ -54,13 +54,13 @@ function dispatchHoverInEvents(
   }
 }
 
-function dispatchHoverOutEvents(context: EventResponderContext, props: Object) {
+function dispatchHoverEndEvents(context: EventResponderContext, props: Object) {
   const {event, eventTarget} = context;
   if (context.isTargetWithinEventComponent((event: any).relatedTarget)) {
     return;
   }
-  if (props.onHoverOut) {
-    context.dispatchEvent('hoverout', props.onHoverOut, eventTarget, true);
+  if (props.onHoverEnd) {
+    context.dispatchEvent('hoverend', props.onHoverEnd, eventTarget, true);
   }
   if (props.onHoverChange) {
     const hoverChangeEventListener = () => {
@@ -118,15 +118,15 @@ const HoverResponder = {
             state.isInHitSlop = true;
             return;
           }
-          dispatchHoverInEvents(context, props, state);
+          dispatchHoverStartEvents(context, props, state);
           state.isHovered = true;
         }
         break;
       }
       case 'pointerout':
       case 'mouseout': {
         if (state.isHovered && !state.isTouched) {
-          dispatchHoverOutEvents(context, props);
+          dispatchHoverEndEvents(context, props);
           state.isHovered = false;
         }
         state.isInHitSlop = false;
@@ -142,7 +142,7 @@ const HoverResponder = {
                 (event: any).y,
               )
             ) {
-              dispatchHoverInEvents(context, props, state);
+              dispatchHoverStartEvents(context, props, state);
               state.isHovered = true;
               state.isInHitSlop = false;
             }
@@ -153,7 +153,7 @@ const HoverResponder = {
               (event: any).y,
             )
           ) {
-            dispatchHoverOutEvents(context, props);
+            dispatchHoverEndEvents(context, props);
             state.isHovered = false;
             state.isInHitSlop = true;
           }
@@ -162,7 +162,7 @@ const HoverResponder = {
       }
       case 'pointercancel': {
         if (state.isHovered && !state.isTouched) {
-          dispatchHoverOutEvents(context, props);
+          dispatchHoverEndEvents(context, props);
           state.isHovered = false;
           state.isTouched = false;
         }

packages/react-events/src/__tests__/Hover-test.internal.js

@@ -0,0 +1,102 @@
+/**
+ * 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.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+let React;
+let ReactFeatureFlags;
+let ReactDOM;
+let Hover;
+
+describe('Hover event responder', () => {
+  let container;
+
+  beforeEach(() => {
+    jest.resetModules();
+    ReactFeatureFlags = require('shared/ReactFeatureFlags');
+    ReactFeatureFlags.enableEventAPI = true;
+    React = require('react');
+    ReactDOM = require('react-dom');
+    Hover = require('react-events/hover');
+
+    container = document.createElement('div');
+    document.body.appendChild(container);
+  });
+
+  afterEach(() => {
+    document.body.removeChild(container);
+    container = null;
+  });
+
+  it('should support onHover', () => {
+    let divRef = React.createRef();
+    let events = [];
+
+    function handleOnHover(e) {
+      if (e) {
+        events.push('hover in');
+      } else {
+        events.push('hover out');
+      }
+    }
+
+    function Component() {
+      return (
+        <Hover onHoverChange={handleOnHover}>
+          <div ref={divRef}>Hover me!</div>
+        </Hover>
+      );
+    }
+
+    ReactDOM.render(<Component />, container);
+
+    const mouseOverEvent = document.createEvent('Event');
+    mouseOverEvent.initEvent('mouseover', true, true);
+    divRef.current.dispatchEvent(mouseOverEvent);
+
+    const mouseOutEvent = document.createEvent('Event');
+    mouseOutEvent.initEvent('mouseout', true, true);
+    divRef.current.dispatchEvent(mouseOutEvent);
+
+    expect(events).toEqual(['hover in', 'hover out']);
+  });
+
+  it('should support onHoverStart and onHoverEnd', () => {
+    let divRef = React.createRef();
+    let events = [];
+
+    function handleOnHoverStart() {
+      events.push('onHoverStart');
+    }
+
+    function handleOnHoverEnd() {
+      events.push('onHoverEnd');
+    }
+
+    function Component() {
+      return (
+        <Hover onHoverStart={handleOnHoverStart} onHoverEnd={handleOnHoverEnd}>
+          <div ref={divRef}>Hover me!</div>
+        </Hover>
+      );
+    }
+
+    ReactDOM.render(<Component />, container);
+
+    const mouseOverEvent = document.createEvent('Event');
+    mouseOverEvent.initEvent('mouseover', true, true);
+    divRef.current.dispatchEvent(mouseOverEvent);
+
+    const mouseOutEvent = document.createEvent('Event');
+    mouseOutEvent.initEvent('mouseout', true, true);
+    divRef.current.dispatchEvent(mouseOutEvent);
+
+    expect(events).toEqual(['onHoverStart', 'onHoverEnd']);
+  });
+});