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+---
+title: Object.keys()
+slug: Web/JavaScript/Reference/Global_Objects/Object/keys
+tags:
+  - 'CCAC: Chrome Console Auto Copy'
+  - ECMAScript 5
+  - JavaScript
+  - Method
+  - Object
+translation_of: Web/JavaScript/Reference/Global_Objects/Object/keys
+---
+<p>{{JSRef}}</p>
+
+<p><code><strong>Object.keys()</strong></code> 方法会返回一个由一个给定对象的自身可枚举属性组成的数组，数组中属性名的排列顺序和正常循环遍历该对象时返回的顺序一致 。</p>
+
+<h2 id="Syntax" name="Syntax">语法</h2>
+
+<pre class="syntaxbox"><code>Object.keys(<var>obj</var>)</code></pre>
+
+<h3 id="Parameters" name="Parameters">参数</h3>
+
+<dl>
+ <dt>obj</dt>
+ <dd>要返回其枚举自身属性的对象。</dd>
+</dl>
+
+<h3 id="返回值">返回值</h3>
+
+<p>一个表示给定对象的所有可枚举属性的字符串数组。</p>
+
+<h2 id="Description" name="Description" style="margin-bottom: 20px; line-height: 30px;">描述</h2>
+
+<p><code>Object.keys</code> 返回一个所有元素为字符串的数组，其元素来自于从给定的<code>object</code>上面可直接枚举的属性。这些属性的顺序与手动遍历该对象属性时的一致。</p>
+
+<h2 id="例子">例子</h2>
+
+<pre class="brush: js">// simple array
+var arr = ['a', 'b', 'c'];
+console.log(Object.keys(arr)); // console: ['0', '1', '2']
+
+// array like object
+var obj = { 0: 'a', 1: 'b', 2: 'c' };
+console.log(Object.keys(obj)); // console: ['0', '1', '2']
+
+// array like object with random key ordering
+var anObj = { 100: 'a', 2: 'b', 7: 'c' };
+console.log(Object.keys(anObj)); // console: ['2', '7', '100']
+
+// getFoo is a property which isn't enumerable
+var myObj = Object.create({}, {
+  getFoo: {
+    value: function () { return this.foo; }
+  }
+});
+myObj.foo = 1;
+console.log(Object.keys(myObj)); // console: ['foo']</pre>
+
+<p>如果你想获取一个对象的所有属性,，甚至包括不可枚举的，请查看{{jsxref("Object.getOwnPropertyNames")}}。</p>
+
+<h2 id="注意">注意</h2>
+
+<p>在ES5里，如果此方法的参数不是对象（而是一个原始值），那么它会抛出 TypeError。在ES2015中，非对象的参数将被强制转换为一个对象。</p>
+
+<pre class="brush: js">Object.keys("foo");
+// TypeError: "foo" is not an object (ES5 code)
+
+Object.keys("foo");
+// ["0", "1", "2"]                   (ES2015 code)</pre>
+
+<h2 id="Polyfill">Polyfill</h2>
+
+<p>要在原生不支持的旧环境中添加兼容的<code>Object.keys</code>，请复制以下代码段：</p>
+
+<pre class="brush: js">if (!Object.keys) {
+  Object.keys = (function () {
+    var hasOwnProperty = Object.prototype.hasOwnProperty,
+        hasDontEnumBug = !({toString: null}).propertyIsEnumerable('toString'),
+        dontEnums = [
+          'toString',
+          'toLocaleString',
+          'valueOf',
+          'hasOwnProperty',
+          'isPrototypeOf',
+          'propertyIsEnumerable',
+          'constructor'
+        ],
+        dontEnumsLength = dontEnums.length;
+
+    return function (obj) {
+      if (typeof obj !== 'object' &amp;&amp; typeof obj !== 'function' || obj === null) throw new TypeError('Object.keys called on non-object');
+
+      var result = [];
+
+      for (var prop in obj) {
+        if (hasOwnProperty.call(obj, prop)) result.push(prop);
+      }
+
+      if (hasDontEnumBug) {
+        for (var i=0; i &lt; dontEnumsLength; i++) {
+          if (hasOwnProperty.call(obj, dontEnums[i])) result.push(dontEnums[i]);
+        }
+      }
+      return result;
+    }
+  })()
+};
+</pre>
+
+<p>上面的代码在IE7（也许IE8也是）下有个问题，就是如果传入一个来自其他 window 对象下的对象时，不可枚举的属性也会获取到。</p>
+
+<p>另一个简单的实现，参见<a class="external" href="http://tokenposts.blogspot.com.au/2012/04/javascript-objectkeys-browser.html">Javascript - Object.keys Browser Compatibility</a>。</p>
+
+<h2 id="规范" style="margin-bottom: 20px; line-height: 30px;">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('ES5.1', '#sec-15.2.3.14', 'Object.keys')}}</td>
+   <td>{{Spec2('ES5.1')}}</td>
+   <td>Initial definition.<br>
+    Implemented in JavaScript 1.8.5</td>
+  </tr>
+  <tr>
+   <td>{{SpecName('ES6', '#sec-object.keys', 'Object.keys')}}</td>
+   <td>{{Spec2('ES6')}}</td>
+   <td></td>
+  </tr>
+  <tr>
+   <td>{{SpecName('ESDraft', '#sec-object.keys', 'Object.keys')}}</td>
+   <td>{{Spec2('ESDraft')}}</td>
+   <td></td>
+  </tr>
+ </tbody>
+</table>
+
+<h2 id="浏览器兼容">浏览器兼容</h2>
+
+<div>
+
+
+<p>{{Compat("javascript.builtins.Object.keys")}}</p>
+</div>
+
+<h2 id="See_also" name="See_also">相关链接</h2>
+
+<ul>
+ <li><a href="https://developer.mozilla.org/en-US/docs/Enumerability_and_ownership_of_properties">Enumerability and ownership of properties</a></li>
+ <li>{{jsxref("Object.prototype.propertyIsEnumerable()")}}</li>
+ <li>{{jsxref("Object.create()")}}</li>
+ <li>{{jsxref("Object.getOwnPropertyNames()")}}</li>
+ <li>{{jsxref("Object.values()")}}</li>
+ <li>{{jsxref("Object.entries()")}}</li>
+</ul>