Array Iterator next should check for own property

src/array-iterator.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 'use strict';
 
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
@@ skipping 20 matching lines @@
 
 // 15.19.4.3.4 CreateItrResultObject
 function CreateIteratorResultObject(value, done) {
   return {value: value, done: done};
 }
 
 
 // 15.4.5.2.2 ArrayIterator.prototype.next( )
 function ArrayIteratorNext() {
   var iterator = ToObject(this);
-  var array = GET_PRIVATE(iterator, arrayIteratorObjectSymbol);
-  if (!array) {
+
+  if (!HAS_PRIVATE(iterator, arrayIteratorObjectSymbol)) {
     throw MakeTypeError('incompatible_method_receiver',
                         ['Array Iterator.prototype.next']);
   }
 
+  var array = GET_PRIVATE(iterator, arrayIteratorObjectSymbol);
+  if (IS_UNDEFINED(array)) {
+    return CreateIteratorResultObject(UNDEFINED, true);
+  }
+
   var index = GET_PRIVATE(iterator, arrayIteratorNextIndexSymbol);
   var itemKind = GET_PRIVATE(iterator, arrayIterationKindSymbol);
   var length = TO_UINT32(array.length);
 
   // "sparse" is never used.
 
   if (index >= length) {
-    SET_PRIVATE(iterator, arrayIteratorNextIndexSymbol, INFINITY);
+    SET_PRIVATE(iterator, arrayIteratorObjectSymbol, UNDEFINED);
     return CreateIteratorResultObject(UNDEFINED, true);
   }
 
   SET_PRIVATE(iterator, arrayIteratorNextIndexSymbol, index + 1);
 
-  if (itemKind == ITERATOR_KIND_VALUES)
+  if (itemKind == ITERATOR_KIND_VALUES) {
     return CreateIteratorResultObject(array[index], false);
+  }
 
-  if (itemKind == ITERATOR_KIND_ENTRIES)
+  if (itemKind == ITERATOR_KIND_ENTRIES) {
     return CreateIteratorResultObject([index, array[index]], false);
+  }
 
   return CreateIteratorResultObject(index, false);
 }
 
 
 function ArrayEntries() {
   return CreateArrayIterator(this, ITERATOR_KIND_ENTRIES);
 }
 
 
@@ skipping 23 matching lines @@
 function ExtendArrayPrototype() {
   %CheckIsBootstrapping();
 
   InstallFunctions($Array.prototype, DONT_ENUM, $Array(
     'entries', ArrayEntries,
     'values', ArrayValues,
     'keys', ArrayKeys
   ));
 }
 ExtendArrayPrototype();