uTools-Manuals/docs/javascript/Reference/Global_Objects/GeneratorFunction.html

<article id="wikiArticle">
<div></div>
<p><strong><code>GeneratorFunction</code>构造器</strong>生成新的<a href="Reference/Statements/function*" title="function* 这种声明方式(function关键字后跟一个星号）会定义一个生成器函数 (generator function)，它返回一个  Generator  对象。"><code>生成器函数</code></a> 对象。在JavaScript中，生成器函数实际上都是<code>GeneratorFunction</code>的实例对象。</p>
<p>注意，<code>GeneratorFunction</code>并不是一个全局对象。它可以通过下面的代码获取。</p>
<pre><code  class="language-javascript">Object.getPrototypeOf(function*(){}).constructor
</code></pre>
<h2 id="Syntax" name="Syntax">语法</h2>
<pre><code class="language-javascript"><code>new GeneratorFunction ([<var>arg1</var>[, <var>arg2</var>[, ...<var>argN</var>]],] <var>functionBody</var>)</code></code></pre>
<h3 id="Parameters" name="Parameters">参数</h3>
<dl>
<dt><code>arg1, arg2, ... arg<em>N</em></code></dt>
<dd>函数使用的名称作为形式参数名称。每个必须是一个字符串，对应于一个有效的JavaScript标识符或这样的字符串的列表，用逗号分隔；如“<code>x</code>”，“<code>theValue</code>”或“<code>a,b</code>”。</dd>
<dt><code>functionBody</code></dt>
<dd>一个包含多条表示JavaScript函数体语句的字符串。</dd>
</dl>
<h2 id="Description" name="Description">描述</h2>
<p>当创建函数时，将使用<code>GeneratorFunction</code>构造函数创建的<a href="Reference/Statements/function*" title="function* 这种声明方式(function关键字后跟一个星号）会定义一个生成器函数 (generator function)，它返回一个  Generator  对象。"><code>生成器函数</code></a>对象进行解析。这比使用<a href="Reference/Statements/function*" title="function* 这种声明方式(function关键字后跟一个星号）会定义一个生成器函数 (generator function)，它返回一个  Generator  对象。"><code>function* 表达式</code></a> 声明生成器函数效率更低，并且在代码中调用它，因为这些函数与其余的代码一起被解析。</p>
<p>传递给函数的所有参数按照它们被传递的顺序被视为要创建的函数中参数的标识符的名称。</p>
<div class="note">
<p><strong>提示：</strong>使用<code>GeneratorFunction</code>构造函数创建的<a href="Reference/Statements/function*" title="function* 这种声明方式(function关键字后跟一个星号）会定义一个生成器函数 (generator function)，它返回一个  Generator  对象。"><code>生成器函数</code></a>不会为其创建上下文创建闭包；它们始终在全局范围内创建。当运行它们时，它们只能访问自己的本地变量和全局变量，而不是从<code>GeneratorFunction</code>构造函数调用的范围的变量。这与使用<a href="Reference/Global_Objects/eval" title="执行指定代码之后的返回值。如果返回值为空，返回undefined"><code>eval</code></a>与生成函数表达式的代码不同。</p>
</div>
<p>将<code>GeneratorFunction</code>构造函数调用为函数（不使用<code>new</code>运算符）与将其作为构造函数调用的效果相同。</p>
<h2 id="Properties" name="Properties">属性</h2>
<dl>
<dt><code><strong>GeneratorFunction.length</strong></code></dt>
<dd><code>GeneratorFunction</code>构造函数的 length 属性值为 1。</dd>
<dt><a href="Reference/Global_Objects/GeneratorFunction/prototype" title="GeneratorFunction.prototype属性是GeneratorFunction的原型对象。"><code>GeneratorFunction.prototype</code></a></dt>
<dd>允许向所有生成器函数对象添加属性。</dd>
</dl>
<h2 id="GeneratorFunction_原型对象"><code>GeneratorFunction</code> 原型对象</h2>
<h3 id="属性">属性</h3>
<div><dl>
<dt><code><strong>GeneratorFunction.constructor</strong></code></dt>
<dd>初始值是 <a href="Reference/Global_Objects/GeneratorFunction" title="GeneratorFunction构造器生成新的生成器函数 对象。在JavaScript中，生成器函数实际上都是GeneratorFunction的实例对象。"><code>GeneratorFunction</code></a>.</dd>
<dt><code><strong>GeneratorFunction.prototype.prototype</strong></code></dt>
<dd>值是 <code>%GeneratorPrototype%</code>.</dd>
</dl></div>
<h2 id="GeneratorFunction_instances" name="GeneratorFunction_instances"><code>GeneratorFunction</code> 实例</h2>
<p><code>GeneratorFunction</code>实例从<a href="Reference/Global_Objects/GeneratorFunction/prototype" title="GeneratorFunction.prototype属性是GeneratorFunction的原型对象。"><code>GeneratorFunction.prototype</code></a>继承方法和属性。与所有构造函数一样，你可以更改构造函数的原型对象以对所有<code>GeneratorFunction</code>实例进行更改。</p>
<h2 id="Examples" name="Examples">示例</h2>
<h3 id="从GeneratorFunction构造函数创建一个生成器函数">从<code>GeneratorFunction</code>构造函数创建一个生成器函数</h3>
<pre><code  class="language-javascript">var GeneratorFunction = Object.getPrototypeOf(function*(){}).constructor
var g = new GeneratorFunction("a", "yield a * 2");
var iterator = g(10);
console.log(iterator.next().value); // 20
</code></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><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-generatorfunction-objects" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">GeneratorFunction</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>Initial definition.</td>
</tr>
<tr>
<td><a class="external" href="https://tc39.github.io/ecma262/#sec-generatorfunction-objects" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">GeneratorFunction</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容">浏览器兼容</h2>
<div class="hidden">The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out <a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</div>
<p></p><div class="bc-data"><a class="bc-github-link external" href="https://github.com/mdn/browser-compat-data" rel="noopener">Update compatibility data on GitHub</a><table class="bc-table bc-table-js"><thead><tr class="bc-platforms"><td></td><th class="bc-platform-desktop" colspan="6"><span>Desktop</span></th><th class="bc-platform-mobile" colspan="7"><span>Mobile</span></th><th class="bc-platform-server" colspan="1"><span>Server</span></th></tr><tr class="bc-browsers"><td></td><th class="bc-browser-chrome"><span class="bc-head-txt-label bc-head-icon-chrome">Chrome</span></th><th class="bc-browser-edge"><span class="bc-head-txt-label bc-head-icon-edge">Edge</span></th><th class="bc-browser-firefox"><span class="bc-head-txt-label bc-head-icon-firefox">Firefox</span></th><th class="bc-browser-ie"><span class="bc-head-txt-label bc-head-icon-ie">Internet Explorer</span></th><th class="bc-browser-opera"><span class="bc-head-txt-label bc-head-icon-opera">Opera</span></th><th class="bc-browser-safari"><span class="bc-head-txt-label bc-head-icon-safari">Safari</span></th><th class="bc-browser-webview_android"><span class="bc-head-txt-label bc-head-icon-webview_android">Android webview</span></th><th class="bc-browser-chrome_android"><span class="bc-head-txt-label bc-head-icon-chrome_android">Chrome for Android</span></th><th class="bc-browser-edge_mobile"><span class="bc-head-txt-label bc-head-icon-edge_mobile">Edge Mobile</span></th><th class="bc-browser-firefox_android"><span class="bc-head-txt-label bc-head-icon-firefox_android">Firefox for Android</span></th><th class="bc-browser-opera_android"><span class="bc-head-txt-label bc-head-icon-opera_android">Opera for Android</span></th><th class="bc-browser-safari_ios"><span class="bc-head-txt-label bc-head-icon-safari_ios">Safari on iOS</span></th><th class="bc-browser-samsunginternet_android"><span class="bc-head-txt-label bc-head-icon-samsunginternet_android">Samsung Internet</span></th><th class="bc-browser-nodejs"><span class="bc-head-txt-label bc-head-icon-nodejs">Node.js</span></th></tr></thead><tbody><tr><th scope="row"><code>GeneratorFunction</code></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              26</td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
              No</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-unknown bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-unknown bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              26</td><td class="bc-supports-unknown bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-unknown bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-unknown bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td></tr><tr><th scope="row"><a href="Reference/Global_Objects/GeneratorFunction/prototype"><code>prototype</code></a></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              26</td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
<span>No support</span>
</abbr>
              No</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-unknown bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-unknown bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              26</td><td class="bc-supports-unknown bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-unknown bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
              Yes</td><td class="bc-supports-unknown bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr title="Compatibility unknown; please update this.">
                ?
              </abbr></td></tr></tbody></table><section class="bc-legend" id="sect1"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-yes bc-supports">
<abbr class="bc-level bc-level-yes only-icon" title="Full support">
<span>Full support</span>
                  
                </abbr></span></dt><dd>Full support</dd><dt><span class="bc-supports-no bc-supports">
<abbr class="bc-level bc-level-no only-icon" title="No support">
<span>No support</span>
                  
                </abbr></span></dt><dd>No support</dd><dt><span class="bc-supports-unknown bc-supports">
<abbr class="bc-level bc-level-unknown only-icon" title="Compatibility unknown">
<span>Compatibility unknown</span>
                  
                </abbr></span></dt><dd>Compatibility unknown</dd></dl></section></div><p></p>
<h2 id="See_also" name="See_also">相关链接</h2>
<ul>
<li><a href="Reference/Statements/function*" title="function* 这种声明方式(function关键字后跟一个星号）会定义一个生成器函数 (generator function)，它返回一个  Generator  对象。"><code>function* function</code></a></li>
<li><a href="Reference/Operators/function*" title="function*关键字可以在表达式内部定义一个生成器函数。"><code>function* expression</code></a></li>
<li><a href="Reference/Global_Objects/Function" title="Function 构造函数 创建一个新的Function对象。 在 JavaScript 中, 每个函数实际上都是一个Function对象。"><code>Function</code></a></li>
<li><a href="Reference/Statements/function" title="函数声明定义一个具有指定参数的函数。"><code>function statement</code></a></li>
<li><a href="Reference/Operators/function" title="function 关键字可以用来在一个表达式中定义一个函数。"><code>function expression</code></a></li>
<li><a href="Reference/Functions_and_function_scope" title="此页面仍未被本地化, 期待您的翻译!">Functions and function scope</a></li>
</ul>
</article>