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---
title: Generator
slug: Web/JavaScript/Reference/Global_Objects/Generator
tags:
- ECMAScript 2015
- Generator
- JavaScript
- Legacy Generator
- Legacy Iterator
- 参考
- 生成器
translation_of: Web/JavaScript/Reference/Global_Objects/Generator
---
<div>{{JSRef}} </div>
<p><strong>生成器</strong>对象是由一个 {{jsxref("Statements/function*", "generator function", "", 1)}} 返回的,并且它符合<a href="/zh-CN/docs/Web/JavaScript/Reference/Iteration_protocols#iterable">可迭代协议</a>和<a href="/zh-CN/docs/Web/JavaScript/Reference/Iteration_protocols#iterator">迭代器协议</a>。</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox">function* gen() {
yield 1;
yield 2;
yield 3;
}
let g = gen();
// "Generator { }"</pre>
<h2 id="方法">方法</h2>
<dl>
<dt>{{jsxref("Generator.prototype.next()")}}</dt>
<dd>返回一个由 {{jsxref("Operators/yield", "yield")}}表达式生成的值。</dd>
<dt>{{jsxref("Generator.prototype.return()")}}</dt>
<dd>返回给定的值并结束生成器。</dd>
<dt>{{jsxref("Generator.prototype.throw()")}}</dt>
<dd>向生成器抛出一个错误。</dd>
</dl>
<h2 id="示例">示例</h2>
<h3 id="一个无限迭代器">一个无限迭代器</h3>
<pre class="brush: js">function* idMaker(){
let index = 0;
while(true)
yield index++;
}
let gen = idMaker(); // "Generator { }"
console.log(gen.next().value);
// 0
console.log(gen.next().value);
// 1
console.log(gen.next().value);
// 2
// ...</pre>
<h2 id="传统的生成器对象">传统的生成器对象</h2>
<p>Firefox (SpiderMonkey) 在 <a href="/en-US/docs/Web/JavaScript/New_in_JavaScript/1.7">JavaScript 1.7</a> 中也实现了一个较早版本的生成器，其中函数声明中的星号（*）不是必需的 (只需在函数体中使用<code style="font-style: normal;">yield</code> 关键字)。但是，旧式生成器已弃用。不要使用它们;他们将被删除 ({{bug(1083482)}})。</p>
<h3 id="传统的生成器方法">传统的生成器方法</h3>
<dl>
<dt><code>Generator.prototype.next() </code>{{non-standard_inline}}</dt>
<dd>返回 {{jsxref("Operators/yield", "yield")}} 表达式产生的值. 与ES2015 生成器对象的next()方法对应.</dd>
<dt><code>Generator.prototype.close()</code> {{non-standard_inline}}</dt>
<dd>关闭生成器，因此执行该函数后调用<code>next()函数时将会抛出</code> {{jsxref("StopIteration")}} 错误. 与ES2015 生成器对象的return()方法对应..</dd>
<dt><code>Generator.prototype.send()</code> {{non-standard_inline}}</dt>
<dd>用于将值发送到生成器。 该值由 {{jsxref("Operators/yield", "yield")}} 表达式返回, 并且返回下一个 {{jsxref("Operators/yield", "yield")}} 表达式产生的值. <code>send(x)</code> 对应于ES2015生成器对象中的 <code>next(x)</code></dd>
<dt><strong><code>Generator.</code></strong><code>prototype.</code><strong><code>throw()</code> </strong> {{non-standard_inline}}</dt>
<dd>向生成器抛出错误. 与ES2015 生成器对象的throw()方法对应.</dd>
</dl>
<h3 id="旧生成器对象示例">旧生成器对象示例</h3>
<pre class="brush: js">function fibonacci() {
var a = yield 1;
yield a * 2;
}
var it = fibonacci();
console.log(it); // "Generator { }"
console.log(it.next()); // 1
console.log(it.send(10)); // 20
console.log(it.close()); // undefined
console.log(it.next()); // throws StopIteration (as the generator is now closed)
</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-generator-objects', 'Generator objects')}}</td>
<td>{{Spec2('ES2015')}}</td>
<td>Initial definition.</td>
</tr>
<tr>
<td>{{SpecName('ESDraft', '#sec-generator-objects', 'Generator objects')}}</td>
<td>{{Spec2('ESDraft')}}</td>
<td></td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p>{{Compat("javascript.builtins.Generator")}}</p>
<h2 id="See_also" name="See_also">相关链接</h2>
<h3 id="Legacy_generators">Legacy generators</h3>
<ul>
<li>{{jsxref("Statements/Legacy_generator_function", "The legacy generator function", "", 1)}}</li>
<li>{{jsxref("Operators/Legacy_generator_function", "The legacy generator function expression", "", 1)}}</li>
<li>{{jsxref("StopIteration")}}</li>
<li><a href="/en-US/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features/The_legacy_Iterator_protocol">The legacy Iterator protocol</a></li>
</ul>
<h3 id="ES2015_generators">ES2015 generators</h3>
<ul>
<li>{{jsxref("Functions", "Functions", "", 1)}}</li>
<li>{{jsxref("Statements/function", "function")}}</li>
<li>{{jsxref("Operators/function", "function expression")}}</li>
<li>{{jsxref("Function")}}</li>
<li>{{jsxref("Statements/function*", "function*")}}</li>
<li>{{jsxref("Operators/function*", "function* expression")}}</li>
<li>{{jsxref("GeneratorFunction")}}</li>
<li><a href="/en-US/docs/Web/JavaScript/Guide/The_Iterator_protocol">The Iterator protocol</a></li>
</ul>
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