|  | // Copyright (c) 2012, 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 | 
|  |  | 
|  | library JsInterop1Test; | 
|  |  | 
|  | import 'package:async_helper/async_helper.dart'; | 
|  | import 'dart:async'; | 
|  | import 'dart:html'; | 
|  |  | 
|  | injectSource(code) { | 
|  | final script = new ScriptElement(); | 
|  | script.type = 'text/javascript'; | 
|  | script.innerHtml = code; | 
|  | document.body!.append(script); | 
|  | } | 
|  |  | 
|  | main() { | 
|  | asyncTest(() async { | 
|  | var subscription; | 
|  | var completer = Completer<void>(); | 
|  | subscription = window.onMessage.listen((e) { | 
|  | if (!completer.isCompleted && e.data == 'hello') { | 
|  | completer.complete(); | 
|  | subscription.cancel(); | 
|  | } | 
|  | }); | 
|  | injectSource("window.postMessage('hello', '*');"); | 
|  |  | 
|  | await completer.future; | 
|  | }); | 
|  | } |