---
title: AsyncIterator
slug: Web/JavaScript/Reference/Global_Objects/AsyncIterator
tags:
  - 异步迭代器
  - 类
translation_of: Web/JavaScript/Reference/Global_Objects/AsyncIterator
---
<p>{{JSRef}}{{Draft}}</p>

<p><strong><code>AsyncIterator</code></strong> 全局对象是一个提供辅助方法的抽象类，与暴露在{{JSxRef("Array")}} 实例上的那些类似。</p>

<h2 id="构造函数">构造函数</h2>

<dl>
 <dt>{{JSxRef("AsyncIterator.AsyncIterator", "AsyncIterator()")}} </dt>
 <dd>一个抽象构造函数，仅能够通过 {{JSxRef("Operators/super", "super()")}} 来调用。</dd>
</dl>

<h2 id="属性">属性</h2>

<dl>
 <dt><code>AsyncIterator.prototype</code></dt>
 <dd><code>%AsyncIteratorPrototype%</code> 内部对象。</dd>
</dl>

<h2 id="方法">方法</h2>

<dl>
 <dt>{{JSxRef("AsyncIterator.from()")}} </dt>
 <dd>等同于在传入的对象上调用 <code>@@asyncIterator</code> 。</dd>
</dl>

<h2 id="AsyncIterator_原型"><code>AsyncIterator</code> 原型</h2>

<h3 id="原型属性">原型属性</h3>

<dl>
 <dt><code>AsyncIterator.prototype.constructor</code></dt>
 <dd>指定创建对的象原型的函数.</dd>
 <dt><code>AsyncIterator.prototype[@@toStringTag]</code> </dt>
 <dd><code>字符串 "Iterator"</code>.</dd>
</dl>

<h3 id="原型方法">原型方法</h3>

<dl>
 <dt>{{JSxRef("AsyncIterator.prototype.map()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.filter()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.take()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.drop()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.asIndexedPairs()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.flatMap()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.reduce()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.toArray()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.forEach()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.some()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.every()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.find()")}} </dt>
 <dd>...</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.@@iterator()", "AsyncIterator.prototype[@@iterator]()")}}</dt>
 <dd>返回该 <code>AsyncIterator</code> 实例。</dd>
</dl>

<h2 id="实现方法">实现方法</h2>

<dl>
 <dt>{{JSxRef("AsyncIterator.prototype.next()", "&lt;<var>implementation</var>&gt;.prototype.next()")}}</dt>
 <dd>获取 <code>AsyncIterator</code> 中的下一项</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.return()", "&lt;<var>implementation</var>&gt;.prototype.next()")}}{{Optional_Inline}}</dt>
 <dd>返回给出的值，并结束迭代。</dd>
 <dt>{{JSxRef("AsyncIterator.prototype.throw()", "&lt;<var>implementation</var>&gt;.prototype.next()")}}{{Optional_Inline}}</dt>
 <dd>抛出一个迭代器错误（同时也终止了迭代器，除非是在该迭代器内部被捕获）。</dd>
</dl>

<h2 id="规范">规范</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td><a href="https://tc39.es/proposal-iterator-helpers/#sec-asynciterator-constructor">ESNext Iterator Helpers Proposal</a></td>
   <td><span class="spec-Draft">Stage 2 Draft</span></td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>



<p>{{Compat("javascript.builtins.AsyncIterator")}}</p>

<h2 id="另请参阅">另请参阅</h2>

<ul>
 <li>{{JSxRef("Iteration_protocols", "Iteration protocols", "", "1")}}</li>
 <li>{{JSxRef("Generator")}}</li>
 <li>{{JSxRef("Global_Objects/AsyncGenerator", "AsyncGenerator")}}</li>
 <li>{{JSxRef("Iterator")}} </li>
</ul>