react app

react-app/node_modules/react/lib/EnterLeaveEventPlugin.js

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+/**
+ * Copyright 2013-2015, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule EnterLeaveEventPlugin
+ * @typechecks static-only
+ */
+
+'use strict';
+
+var EventConstants = require("./EventConstants");
+var EventPropagators = require("./EventPropagators");
+var SyntheticMouseEvent = require("./SyntheticMouseEvent");
+
+var ReactMount = require("./ReactMount");
+var keyOf = require("./keyOf");
+
+var topLevelTypes = EventConstants.topLevelTypes;
+var getFirstReactDOM = ReactMount.getFirstReactDOM;
+
+var eventTypes = {
+  mouseEnter: {
+    registrationName: keyOf({onMouseEnter: null}),
+    dependencies: [
+      topLevelTypes.topMouseOut,
+      topLevelTypes.topMouseOver
+    ]
+  },
+  mouseLeave: {
+    registrationName: keyOf({onMouseLeave: null}),
+    dependencies: [
+      topLevelTypes.topMouseOut,
+      topLevelTypes.topMouseOver
+    ]
+  }
+};
+
+var extractedEvents = [null, null];
+
+var EnterLeaveEventPlugin = {
+
+  eventTypes: eventTypes,
+
+  /**
+   * For almost every interaction we care about, there will be both a top-level
+   * `mouseover` and `mouseout` event that occurs. Only use `mouseout` so that
+   * we do not extract duplicate events. However, moving the mouse into the
+   * browser from outside will not fire a `mouseout` event. In this case, we use
+   * the `mouseover` top-level event.
+   *
+   * @param {string} topLevelType Record from `EventConstants`.
+   * @param {DOMEventTarget} topLevelTarget The listening component root node.
+   * @param {string} topLevelTargetID ID of `topLevelTarget`.
+   * @param {object} nativeEvent Native browser event.
+   * @return {*} An accumulation of synthetic events.
+   * @see {EventPluginHub.extractEvents}
+   */
+  extractEvents: function(
+      topLevelType,
+      topLevelTarget,
+      topLevelTargetID,
+      nativeEvent) {
+    if (topLevelType === topLevelTypes.topMouseOver &&
+        (nativeEvent.relatedTarget || nativeEvent.fromElement)) {
+      return null;
+    }
+    if (topLevelType !== topLevelTypes.topMouseOut &&
+        topLevelType !== topLevelTypes.topMouseOver) {
+      // Must not be a mouse in or mouse out - ignoring.
+      return null;
+    }
+
+    var win;
+    if (topLevelTarget.window === topLevelTarget) {
+      // `topLevelTarget` is probably a window object.
+      win = topLevelTarget;
+    } else {
+      // TODO: Figure out why `ownerDocument` is sometimes undefined in IE8.
+      var doc = topLevelTarget.ownerDocument;
+      if (doc) {
+        win = doc.defaultView || doc.parentWindow;
+      } else {
+        win = window;
+      }
+    }
+
+    var from, to;
+    if (topLevelType === topLevelTypes.topMouseOut) {
+      from = topLevelTarget;
+      to =
+        getFirstReactDOM(nativeEvent.relatedTarget || nativeEvent.toElement) ||
+        win;
+    } else {
+      from = win;
+      to = topLevelTarget;
+    }
+
+    if (from === to) {
+      // Nothing pertains to our managed components.
+      return null;
+    }
+
+    var fromID = from ? ReactMount.getID(from) : '';
+    var toID = to ? ReactMount.getID(to) : '';
+
+    var leave = SyntheticMouseEvent.getPooled(
+      eventTypes.mouseLeave,
+      fromID,
+      nativeEvent
+    );
+    leave.type = 'mouseleave';
+    leave.target = from;
+    leave.relatedTarget = to;
+
+    var enter = SyntheticMouseEvent.getPooled(
+      eventTypes.mouseEnter,
+      toID,
+      nativeEvent
+    );
+    enter.type = 'mouseenter';
+    enter.target = to;
+    enter.relatedTarget = from;
+
+    EventPropagators.accumulateEnterLeaveDispatches(leave, enter, fromID, toID);
+
+    extractedEvents[0] = leave;
+    extractedEvents[1] = enter;
+
+    return extractedEvents;
+  }
+
+};
+
+module.exports = EnterLeaveEventPlugin;