fix: patch MutationObserver

Author: btford

Diff for: test/zone.spec.js

@@ -324,6 +324,42 @@ describe('Zone.patch', function () {
 
   });
 
+  describe('MutationObserver', function () {
+    it('should work', function () {
+      if (!window.MutationObserver) {
+        console.log('WARNING: skipping MutationObserver test (missing this API)');
+        return;
+      }
+
+      var flag = false,
+          elt = document.createElement('div'),
+          hasParent;
+
+      runs(function () {
+        var ob = new MutationObserver(function () {
+          hasParent = !!window.zone.parent;
+          dump('yo')
+          flag = true;
+        });
+
+        ob.observe(elt, {
+          childList: true
+        });
+
+        elt.innerHTML = '<p>hey</p>';
+      });
+
+      waitsFor(function() {
+        return flag;
+      }, 'promise to resolve', 100);
+
+      runs(function() {
+        expect(hasParent).toBe(true);
+      });
+
+    });
+  });
+
   describe('XMLHttpRequest', function () {
 
     it('should work with onreadystatechange', function () {

Diff for: zone.js

@@ -267,6 +267,9 @@ Zone.patch = function patch () {
       'catch'
     ]);
   }
+  if (window.MutationObserver) {
+    Zone.patchClass('MutationObserver');
+  }
 };
 
 //
@@ -315,11 +318,22 @@ Zone.patchViaCapturingAllTheEvents = function () {
 // TODO: wrap some native API
 Zone.patchClass = function (className) {
   var OriginalClass = window[className];
+  if (!OriginalClass) {
+    return;
+  }
   window[className] = function () {
-    this._o = new OriginalClass();
+    var a = Zone.bindArguments(arguments);
+    switch (a.length) {
+      case 0: this._o = new OriginalClass(); break;
+      case 1: this._o = new OriginalClass(a[0]); break;
+      case 2: this._o = new OriginalClass(a[0], a[1]); break;
+      case 3: this._o = new OriginalClass(a[0], a[1], a[2]); break;
+      case 4: this._o = new OriginalClass(a[0], a[1], a[2], a[3]); break;
+      default: throw new Error('what are you even doing?');
+    }
   };
 
-  var instance = (new OriginalClass());
+  var instance = new OriginalClass(className === 'MutationObserver' ? function () {} : undefined);
 
   var prop;
   for (prop in instance) {