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---
title: Map.prototype[@@iterator]()
slug: Web/JavaScript/Reference/Global_Objects/Map/@@iterator
tags:
- ECMAScript 2015
- Iterator
- JavaScript
- Map
- Method
- Prototype
- Reference
translation_of: Web/JavaScript/Reference/Global_Objects/Map/@@iterator
original_slug: Web/JavaScript/Reference/Global_Objects/Map/@@iterator
browser-compat: javascript.builtins.Map.@@iterator
---
<div>{{JSRef}}</div>
<p><code><strong>@@iterator</strong></code><strong> </strong>属性的初始值与 {{jsxref("Map.prototype.entries()", "entries")}} 属性的初始值是同一个函数对象。</p>
<div>{{EmbedInteractiveExample("pages/js/map-prototype-@@iterator.html")}}</div>
<h2 id="语法">语法</h2>
<pre class="syntaxbox"><code><em>myMap</em>[Symbol.iterator]</code></pre>
<h3 id="返回值">返回值</h3>
<p>map 的 <strong>iterator</strong> 函数默认就是 {{jsxref("Map.prototype.entries()", "entries()")}} 函数。</p>
<h2 id="示例">示例</h2>
<h3 id="使用_iterator()">使用 <code>[@@iterator]()</code></h3>
<pre class="brush:js">var myMap = new Map();
myMap.set('0', 'foo');
myMap.set(1, 'bar');
myMap.set({}, 'baz');
var mapIter = myMap[Symbol.iterator]();
//返回的其实是个generator
console.log(mapIter.next().value); // ["0", "foo"]
console.log(mapIter.next().value); // [1, "bar"]
console.log(mapIter.next().value); // [Object, "baz"]
</pre>
<h3 id="在for..of中使用iterator()">在<code>for..of中</code>使用<code>[@@iterator]()</code> </h3>
<pre class="brush:js">var myMap = new Map();
myMap.set('0', 'foo');
myMap.set(1, 'bar');
myMap.set({}, 'baz');
for (const entry of myMap) {
console.log(entry);
}
// ["0", "foo"]
// [1, "bar"]
// [{}, "baz"]
for (var v of myMap) {
console.log(v);
}
// 0: foo
// 1: bar
// [Object]: baz</pre>
<h2 id="规范">规范</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td>{{SpecName('ES2015', '#sec-map.prototype-@@iterator', 'Map.prototype[@@iterator]()')}}</td>
<td>{{Spec2('ES2015')}}</td>
<td>Initial definition.</td>
</tr>
<tr>
<td>{{SpecName('ESDraft', '#sec-map.prototype-@@iterator', 'Map.prototype[@@iterator]()')}}</td>
<td>{{Spec2('ESDraft')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容">浏览器兼容</h2>
<p>{{Compat("javascript.builtins.Map.@@iterator")}}</p>
<h2 id="另见">另见</h2>
<ul>
<li>{{jsxref("Map.prototype.entries()")}}</li>
<li>{{jsxref("Map.prototype.keys()")}}</li>
<li>{{jsxref("Map.prototype.values()")}}</li>
</ul>
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