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<article id="wikiArticle">
<div></div>
<div><code><strong><em>function</em>.name</strong></code> 属性返回函数实例的名称。</div>
<p></p><table class="standard-table">
<thead>
<tr>
<th class="header" colspan="2"><code>Function.name</code> 属性的属性特性：</th>
</tr>
</thead>
<tbody>
<tr>
<td>writable</td>
<td>false</td>
</tr>
<tr>
<td>enumerable</td>
<td>false</td>
</tr>
<tr>
<td>configurable</td>
<td>true</td>
</tr>
</tbody>
</table><p></p>
<div class="note">
<p>请注意，在非标准的ES2015之前的实现中，<code>configurable</code>属性也是<code>false</code> 。</p>
</div>
<h2 id="示例">示例</h2>
<h3 id="函数声明的名称">函数声明的名称</h3>
<p> <code>name</code> 属性返回一个函数声明的名称。</p>
<pre><code class="language-js">function doSomething() { }
doSomething.name; // "doSomething" 
</code></pre>
<h3 id="构造函数的名称">构造函数的名称</h3>
<p>使用<code>new Function(...)</code>语法创建的函数或只是 <code>Function(...) create</code> <a href="Reference/Function" title="此页面仍未被本地化, 期待您的翻译!"><code>Function</code></a>对象及其名称为“anonymous”。</p>
<pre><code class="language-javascript">(new Function).name; // "anonymous"</code></pre>
<h3 id="推断函数名称">推断函数名称</h3>
<p>变量和方法可以从句法位置推断匿名函数的名称（ECMAScript 2015中新增）。</p>
<pre><code class="language-javascript">var f = function() {};
var object = {
someMethod: function() {}
};
console.log(f.name); // "f"
console.log(object.someMethod.name); // "someMethod"</code></pre>
<p style="color: rgb(77, 78, 83);">你可以在 <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。">函数表达式</a>中定义函数的名称:</p>
<pre><code class="language-js">var object = {
someMethod: function object_someMethod() {}
};
console.log(object.someMethod.name); // "object_someMethod"
try { object_someMethod } catch(e) { alert(e); }
// ReferenceError: object_someMethod is not defined
</code></pre>
<p>你不能更改函数的名称，此属性是只读的：</p>
<div class="hidden">
<p>Example below contradicts with what is said at the beginning of this section and doesn't work as described.</p>
</div>
<pre><code class="language-javascript">var object = {
// anonymous
someMethod: function() {}
};
object.someMethod.name = 'otherMethod';
console.log(object.someMethod.name); // someMethod</code></pre>
<p>要更改它，可以使用<a href="Reference/Global_Objects/Object/defineProperty" title="Object.defineProperty() 方法会直接在一个对象上定义一个新属性，或者修改一个对象的现有属性， 并返回这个对象。"><code>Object.defineProperty()</code></a>。</p>
<h3 id="简写方法的名称">简写方法的名称</h3>
<pre><code class="language-javascript">var o = {
foo(){}
};
o.foo.name; // "foo";</code></pre>
<h3 id="绑定函数的名称">绑定函数的名称</h3>
<p><a href="Reference/Global_Objects/Function/bind" title="bind()方法创建一个新的函数，在调用时设置this关键字为提供的值。并在调用新函数时，将给定参数列表作为原函数的参数序列的前若干项。"><code>Function.bind()</code></a> 所创建的函数将会在函数的名称前加上"bound " 。</p>
<pre><code class="language-javascript">function foo() {};
foo.bind({}).name; // "bound foo"</code></pre>
<h3 id="getters_和_setters_的函数名">getters 和 setters 的函数名</h3>
<p>当通过 <code><a href="Reference/Functions/get">get</a></code> 和 <code><a href="Reference/Functions/set">set</a></code> 访问器来存取属性时, "get" 或 "set" 会出现在函数名称前。</p>
<pre><code class="language-javascript">var o = {
get foo(){},
set foo(x){}
};
var descriptor = Object.getOwnPropertyDescriptor(o, "foo");
descriptor.get.name; // "get foo"
descriptor.set.name; // "set foo";</code></pre>
<h3 id="类中的函数名称">类中的函数名称</h3>
<p>你可以使用<code>obj.constructor.name</code>来检查对象的“类”（但请务必阅读以下警告）：</p>
<pre><code class="language-javascript">function Foo() {} // ES2015 Syntax: class Foo {}
var fooInstance = new Foo();
console.log(fooInstance.constructor.name); // logs "Foo"</code></pre>
<div class="warning">
<p><strong>警告：</strong>脚本解释器只有在函数没有名为name的属性时才会设置内置的<code>Function.name</code>属性（参见 <a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-setfunctionname" rel="noopener">9.2.11 of the ECMAScript2015 Language Specification</a>）。但是，ES2015规定由关键字<em>static</em>修饰的静态方法也会被认为是类的属性（ECMAScript2015, <a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-runtime-semantics-classdefinitionevaluation" rel="noopener">14.5.14.21.b</a> + <a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-object-initializer-runtime-semantics-propertydefinitionevaluation" rel="noopener">12.2.6.9</a>）。</p>
</div>
<p>因此，我们无法获取具有静态方法属性<code>name()</code>的几乎任何类的类名称：</p>
<pre><code class="language-javascript">class Foo {
constructor() {}
static name() {}
}
</code></pre>
<p>使用<code>static name()</code>方法<code>Foo.name</code>不再保存实际的类名称，而是引用<code>name()</code>函数对象。 ES2015语法中的上述类定义将在Chrome或Firefox中运行，类似于ES5语法中的以下代码段：</p>
<pre><code class="language-javascript">function Foo() {}
Object.defineProperty(Foo, 'name', { writable: true });
Foo.name = function() {};
</code></pre>
<p>通过<code>fooInstance.constructor.name</code>获取<code>fooInstance</code>类不会给我们所有的类名，而是静态类方法的引用。 例如：</p>
<pre><code class="language-javascript">var fooInstance = new Foo();
console.log(fooInstance.constructor.name); // logs function name()</code></pre>
<p>你也可以从ES5语法示例中看到，在Chrome或Firefox的中静态定义的<code>Foo.name</code>变得可写。内置定义在没有自定义静态定义时是只读的：</p>
<pre><code class="language-javascript">Foo.name = 'Hello';
console.log(Foo.name);
//如果Foo具有静态name()属性，则输出“Hello”，否则为“Foo”
</code></pre>
<p>因此，你不能依赖内置的<code>Function.name</code>属性来保持一个类的名称。</p>
<h3 id="Symbol作为函数名称">Symbol作为函数名称</h3>
<p>如果<a href="Reference/Global_Objects/Symbol" title='Symbol()函数会返回symbol类型的值，该类型具有静态属性和静态方法。它的静态属性会暴露几个内建的成员对象；它的静态方法会暴露全局的symbol注册，且类似于内建对象类，但作为构造函数来说它并不完整，因为它不支持语法："new Symbol()"。'><code>Symbol</code></a> 被用于函数名称，并且这个symbol具有相应的描述符，那么方法的名字就是方括号中的描述符。</p>
<pre><code class="language-javascript">var sym1 = Symbol("foo");
var sym2 = Symbol();
var o = {
[sym1]: function(){},
[sym2]: function(){}
};
o[sym1].name; // "[foo]"
o[sym2].name; // ""
</code></pre>
<h2 id="JavaScript_压缩和_minifiers">JavaScript 压缩和 minifiers</h2>
<div class="warning">
<p><strong>警告：</strong>当使用<code>Function.name</code>和那些JavaScript压缩器（minifiers）或混淆器进行源码转换时要小心。这些工具通常用作JavaScript构建管道的一部分，以在程序部署到生产之前减少程序的大小。但这种转换通常会在构建时更改函数的名称。</p>
</div>
<p>例如下面的代码:</p>
<pre><code class="language-javascript">function Foo() {};
var foo = new Foo();
if (foo.constructor.name === 'Foo') {
console.log("'foo' is an instance of 'Foo'");
} else {
console.log('Oops!');
}</code></pre>
<p>可能被压缩为:</p>
<pre><code class="language-javascript">function a() {};
var b = new a();
if (b.constructor.name === 'Foo') {
console.log("'foo' is an instance of 'Foo'");
} else {
console.log('Oops!');
}
</code></pre>
<p>在未压缩版本中，程序运行到真实分支并打印<code>'foo' is an instance of 'Foo'</code>。 而在压缩版本中，它的行为不同，并且进入else分支。如果您依赖于<code>Function.name</code>，就像上面的示例一样，确保您的构建管道不会更改函数名称，也不要假定函数具有特定的名称。</p>
<article>
<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-name" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">name</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-name" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">name</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</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>name</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>
15</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>
14</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>
1</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-yes bc-browser-safari"><span class="bc-browser-name">Safari</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-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-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</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_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
4</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera 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-safari_ios"><span class="bc-browser-name">Safari iOS</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-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-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
<span>Full support</span>
</abbr>
Yes</td></tr><tr><th scope="row">Configurable: true</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>
43</td><td class="bc-supports-unknown bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr title="Compatibility unknown; please update this.">
?
</abbr></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>
38</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-unknown bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr title="Compatibility unknown; please update this.">
?
</abbr></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-unknown bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr title="Compatibility unknown; please update this.">
?
</abbr></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>
43</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>
38</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>
4.0</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">Inferred names on anonymous functions</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>
51</td><td class="bc-supports-unknown bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr title="Compatibility unknown; please update this.">
?
</abbr></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>
53</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-unknown bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr title="Compatibility unknown; please update this.">
?
</abbr></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-unknown bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr title="Compatibility unknown; please update this.">
?
</abbr></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>
51</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>
53</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>
5.0</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>
</article>
</article>
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