---
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>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">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>