fix(jqLite): deregister special mouseenter / mouseleave events correctly

Closes #12795
Closes #12799

Author: petebacondarwin

src/jqLite.js

@@ -307,17 +307,23 @@ function jqLiteOff(element, type, fn, unsupported) {
       delete events[type];
     }
   } else {
-    forEach(type.split(' '), function(type) {
+
+    var removeHandler = function(type) {
+      var listenerFns = events[type];
       if (isDefined(fn)) {
-        var listenerFns = events[type];
         arrayRemove(listenerFns || [], fn);
-        if (listenerFns && listenerFns.length > 0) {
-          return;
-        }
       }
+      if (!(isDefined(fn) && listenerFns && listenerFns.length > 0)) {
+        removeEventListenerFn(element, type, handle);
+        delete events[type];
+      }
+    };
 
-      removeEventListenerFn(element, type, handle);
-      delete events[type];
+    forEach(type.split(' '), function(type) {
+      removeHandler(type);
+      if (MOUSE_EVENT_MAP[type]) {
+        removeHandler(MOUSE_EVENT_MAP[type]);
+      }
     });
   }
 }
@@ -772,14 +778,17 @@ function createEventHandler(element, events) {
       return event.immediatePropagationStopped === true;
     };
 
+    // Some events have special handlers that wrap the real handler
+    var handlerWrapper = eventFns.specialHandlerWrapper || defaultHandlerWrapper;
+
     // Copy event handlers in case event handlers array is modified during execution.
     if ((eventFnsLength > 1)) {
       eventFns = shallowCopy(eventFns);
     }
 
     for (var i = 0; i < eventFnsLength; i++) {
       if (!event.isImmediatePropagationStopped()) {
-        eventFns[i].call(element, event);
+        handlerWrapper(element, event, eventFns[i]);
       }
     }
   };
@@ -790,6 +799,22 @@ function createEventHandler(element, events) {
   return eventHandler;
 }
 
+function defaultHandlerWrapper(element, event, handler) {
+  handler.call(element, event);
+}
+
+function specialMouseHandlerWrapper(target, event, handler) {
+  // Refer to jQuery's implementation of mouseenter & mouseleave
+  // Read about mouseenter and mouseleave:
+  // http://www.quirksmode.org/js/events_mouse.html#link8
+  var related = event.relatedTarget;
+  // For mousenter/leave call the handler if related is outside the target.
+  // NB: No relatedTarget if the mouse left/entered the browser window
+  if (!related || (related !== target && !jqLiteContains.call(target, related))) {
+    handler.call(target, event);
+  }
+}
+
 //////////////////////////////////////////
 // Functions iterating traversal.
 // These functions chain results into a single
@@ -818,35 +843,28 @@ forEach({
     var types = type.indexOf(' ') >= 0 ? type.split(' ') : [type];
     var i = types.length;
 
-    while (i--) {
-      type = types[i];
+    var addHandler = function(type, specialHandlerWrapper, noEventListener) {
       var eventFns = events[type];
 
       if (!eventFns) {
-        events[type] = [];
-
-        if (type === 'mouseenter' || type === 'mouseleave') {
-          // Refer to jQuery's implementation of mouseenter & mouseleave
-          // Read about mouseenter and mouseleave:
-          // http://www.quirksmode.org/js/events_mouse.html#link8
-
-          jqLiteOn(element, MOUSE_EVENT_MAP[type], function(event) {
-            var target = this, related = event.relatedTarget;
-            // For mousenter/leave call the handler if related is outside the target.
-            // NB: No relatedTarget if the mouse left/entered the browser window
-            if (!related || (related !== target && !jqLiteContains.call(target, related))) {
-              handle(event, type);
-            }
-          });
-
-        } else {
-          if (type !== '$destroy') {
-            addEventListenerFn(element, type, handle);
-          }
+        eventFns = events[type] = [];
+        eventFns.specialHandlerWrapper = specialHandlerWrapper;
+        if (type !== '$destroy' && !noEventListener) {
+          addEventListenerFn(element, type, handle);
         }
-        eventFns = events[type];
       }
+
       eventFns.push(fn);
+    };
+
+    while (i--) {
+      type = types[i];
+      if (MOUSE_EVENT_MAP[type]) {
+        addHandler(MOUSE_EVENT_MAP[type], specialMouseHandlerWrapper);
+        addHandler(type, undefined, true);
+      } else {
+        addHandler(type);
+      }
     }
   },
 

src/ngScenario/browserTrigger.js

@@ -15,6 +15,7 @@
     if (!element) return;
 
     eventData = eventData || {};
+    var relatedTarget = eventData.relatedTarget || element;
     var keys = eventData.keys;
     var x = eventData.x;
     var y = eventData.y;
@@ -84,7 +85,7 @@
       x = x || 0;
       y = y || 0;
       evnt.initMouseEvent(eventType, true, true, window, 0, x, y, x, y, pressed('ctrl'),
-          pressed('alt'), pressed('shift'), pressed('meta'), 0, element);
+          pressed('alt'), pressed('shift'), pressed('meta'), 0, relatedTarget);
     }
 
     /* we're unable to change the timeStamp value directly so this

test/jqLiteSpec.js

@@ -1431,6 +1431,60 @@ describe('jqLite', function() {
     });
 
 
+    it('should correctly deregister the mouseenter/mouseleave listeners', function() {
+      var aElem = jqLite(a);
+      var onMouseenter = jasmine.createSpy('onMouseenter');
+      var onMouseleave = jasmine.createSpy('onMouseleave');
+
+      aElem.on('mouseenter', onMouseenter);
+      aElem.on('mouseleave', onMouseleave);
+      aElem.off('mouseenter', onMouseenter);
+      aElem.off('mouseleave', onMouseleave);
+      aElem.on('mouseenter', onMouseenter);
+      aElem.on('mouseleave', onMouseleave);
+
+      browserTrigger(a, 'mouseover', {relatedTarget: b});
+      expect(onMouseenter).toHaveBeenCalledOnce();
+
+      browserTrigger(a, 'mouseout', {relatedTarget: b});
+      expect(onMouseleave).toHaveBeenCalledOnce();
+    });
+
+
+    it('should call a `mouseenter/leave` listener only once when `mouseenter/leave` and `mouseover/out` '
+       + 'are triggered simultaneously', function() {
+      var aElem = jqLite(a);
+      var onMouseenter = jasmine.createSpy('mouseenter');
+      var onMouseleave = jasmine.createSpy('mouseleave');
+
+      aElem.on('mouseenter', onMouseenter);
+      aElem.on('mouseleave', onMouseleave);
+
+      browserTrigger(a, 'mouseenter', {relatedTarget: b});
+      browserTrigger(a, 'mouseover', {relatedTarget: b});
+      expect(onMouseenter).toHaveBeenCalledOnce();
+
+      browserTrigger(a, 'mouseleave', {relatedTarget: b});
+      browserTrigger(a, 'mouseout', {relatedTarget: b});
+      expect(onMouseleave).toHaveBeenCalledOnce();
+    });
+
+    it('should call a `mouseenter/leave` listener when manually triggering the event', function() {
+      var aElem = jqLite(a);
+      var onMouseenter = jasmine.createSpy('mouseenter');
+      var onMouseleave = jasmine.createSpy('mouseleave');
+
+      aElem.on('mouseenter', onMouseenter);
+      aElem.on('mouseleave', onMouseleave);
+
+      aElem.triggerHandler('mouseenter');
+      expect(onMouseenter).toHaveBeenCalledOnce();
+
+      aElem.triggerHandler('mouseleave');
+      expect(onMouseleave).toHaveBeenCalledOnce();
+    });
+
+
     it('should deregister specific listener within the listener and call subsequent listeners', function() {
       var aElem = jqLite(a),
           clickSpy = jasmine.createSpy('click'),