|  | // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file | 
|  | // for details. All rights reserved. Use of this source code is governed by a | 
|  | // BSD-style license that can be found in the LICENSE file. | 
|  |  | 
|  | part of dart._js_helper; | 
|  |  | 
|  | /// Returns the property [index] of the JavaScript array [array]. | 
|  | getIndex(array, int index) { | 
|  | assert(isJsArray(array)); | 
|  | return JS('var', r'#[#]', array, index); | 
|  | } | 
|  |  | 
|  | /// Returns the length of the JavaScript array [array]. | 
|  | int getLength(array) { | 
|  | assert(isJsArray(array)); | 
|  | return JS<int>('!', r'#.length', array); | 
|  | } | 
|  |  | 
|  | /// Returns whether [value] is a JavaScript array. | 
|  | bool isJsArray(value) { | 
|  | return value is JSArray; | 
|  | } |