fix(forEach): match behaviour of Array.prototype.forEach (ignore missing properties)

src/Angular.js

@@ -245,8 +245,11 @@ function forEach(obj, iterator, context) {
         }
       }
     } else if (isArray(obj) || isArrayLike(obj)) {
+      var isPrimitive = typeof obj !== 'object';
       for (key = 0, length = obj.length; key < length; key++) {
-        iterator.call(context, obj[key], key);
+        if (isPrimitive || key in obj) {
+          iterator.call(context, obj[key], key);
+        }
       }
     } else if (obj.forEach && obj.forEach !== forEach) {
         obj.forEach(iterator, context);

test/AngularSpec.js

@@ -650,6 +650,16 @@ describe('angular', function() {
       forEach(obj, function(value, key) { log.push(key + ':' + value); });
       expect(log).toEqual(['length:2', 'foo:bar']);
     });
+
+
+    it('should not invoke the iterator for indexed properties which are not present in the collection', function() {
+      var log = [];
+      var collection = [];
+      collection[5] = 'SPARSE';
+      forEach(collection, function (item, index) { log.push(item + index); });
+      expect(log.length).toBe(1);
+      expect(log[0]).toBe('SPARSE5');
+    });
   });