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119 lines
12 KiB
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<article id="wikiArticle">
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<div></div>
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<p><code><strong>Object.getOwnPropertyDescriptors()</strong></code> 方法用来获取一个对象的所有自身属性的描述符。</p>
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<h2 id="语法">语法</h2>
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<pre><code class="language-javascript">Object.getOwnPropertyDescriptors(<var>obj</var>)</code></pre>
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<h3 id="参数">参数</h3>
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<dl>
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<dt><code>obj</code></dt>
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<dd>任意对象</dd>
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</dl>
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<h3 id="返回值">返回值</h3>
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<p>所指定对象的所有自身属性的描述符，如果没有任何自身属性，则返回空对象。</p>
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<dl>
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</dl>
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<h2 id="示例">示例</h2>
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<h3 id="浅拷贝一个对象">浅拷贝一个对象</h3>
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<p><a href="Reference/Global_Objects/Object/assign" title="Object.assign() 方法用于将所有可枚举属性的值从一个或多个源对象复制到目标对象。它将返回目标对象。"><code>Object.assign()</code></a> 方法只能拷贝源对象的可枚举的自身属性，同时拷贝时无法拷贝属性的特性们，而且访问器属性会被转换成数据属性，也无法拷贝源对象的原型，该方法配合 <a href="Reference/Global_Objects/Object/create" title="Object.create()方法创建一个新对象，使用现有的对象来提供新创建的对象的__proto__。 （请打开浏览器控制台以查看运行结果。）"><code>Object.create()</code></a> 方法可以实现上面说的这些。</p>
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<pre><code class="language-javascript">Object.create(
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Object.getPrototypeOf(obj),
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Object.getOwnPropertyDescriptors(obj)
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);
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</code></pre>
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<h3 id="创建子类">创建子类</h3>
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<p>创建子类的典型方法是定义子类，将其原型设置为超类的实例，然后在该实例上定义属性。这么写很不优雅，特别是对于 getters 和 setter 而言。 相反，您可以使用此代码设置原型：</p>
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<pre><code class="language-javascript"><code class="language-js"><span class="keyword token">function</span> <span class="function token">superclass</span><span class="punctuation token">(</span><span class="punctuation token">)</span> <span class="punctuation token">{</span><span class="punctuation token">}</span>
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superclass<span class="punctuation token">.</span>prototype <span class="operator token">=</span> <span class="punctuation token">{</span>
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<span class="comment token">// 在这里定义方法和属性</span>
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<span class="punctuation token">}</span><span class="punctuation token">;</span>
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<span class="keyword token">function</span> <span class="function token">subclass</span><span class="punctuation token">(</span><span class="punctuation token">)</span> <span class="punctuation token">{</span><span class="punctuation token">}</span>
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subclass<span class="punctuation token">.</span>prototype <span class="operator token">=</span> Object<span class="punctuation token">.</span><span class="function token">create</span><span class="punctuation token">(</span>superclass<span class="punctuation token">.</span>prototype<span class="punctuation token">,</span> Object<span class="punctuation token">.</span><span class="function token">getOwnPropertyDescriptors</span><span class="punctuation token">(</span><span class="punctuation token">{</span>
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<span class="comment token">// 在这里定义方法和属性</span>
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<span class="punctuation token">}</span><span class="punctuation token">)</span><span class="punctuation token">)</span><span class="punctuation token">;</span></code></code></pre>
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<h2 id="规范">规范</h2>
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<table class="standard-table">
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<tbody>
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<tr>
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<th scope="col">Specification</th>
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<th scope="col">Status</th>
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<th scope="col">Comment</th>
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</tr>
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<tr>
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<td><a class="external" href="https://tc39.github.io/ecma262/#sec-object.getownpropertydescriptors" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">Object.getOwnPropertyDescriptors</small></a></td>
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<td><span class="spec-Draft">Draft</span></td>
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<td>Initial definition in ECMAScript 2017.</td>
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</tr>
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<tr>
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<td><a class="external" href="https://www.ecma-international.org/ecma-262/8.0/#sec-object.getownpropertydescriptors" hreflang="en" lang="en" rel="noopener">ECMAScript 2017 (ECMA-262)<br/><small lang="zh-CN">Object.getOwnPropertyDescriptors</small></a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td> </td>
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</tr>
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</tbody>
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</table>
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<h2 id="浏览器兼容性">浏览器兼容性</h2>
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<div><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>getOwnPropertyDescriptors</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">
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<span>Full support</span>
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</abbr>
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54</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">
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<span>Full support</span>
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</abbr>
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15</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">
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<span>Full support</span>
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</abbr>
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50</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">
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<span>No support</span>
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</abbr>
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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">
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<span>Full support</span>
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</abbr>
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41</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">
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<span>Full support</span>
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</abbr>
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10</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.">
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?
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</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">
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<span>Full support</span>
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</abbr>
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54</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">
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<span>Full support</span>
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</abbr>
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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">
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<span>Full support</span>
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</abbr>
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50</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.">
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?
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</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.">
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?
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</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">
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<span>Full support</span>
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</abbr>
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6.0</td><td class="bc-supports-yes bc-browser-nodejs bc-has-history"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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7.0.0<div class="bc-icons"></div><section class="bc-history" id="sect1"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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7.0.0<div class="bc-icons"></div></dt><dd></dd><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr>
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6.5.0<div class="bc-icons"><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> </div></dt><dd><abbr class="only-icon" title="User must explicitly enable this feature."><span>Disabled</span><i class="ic-disabled"></i></abbr> From version 6.5.0: this feature is behind the <code>--harmony</code> runtime flag.</dd></dl></section></td></tr></tbody></table><section class="bc-legend" id="sect2"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-yes bc-supports">
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<abbr class="bc-level bc-level-yes only-icon" title="Full support">
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<span>Full support</span>
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</abbr></span></dt><dd>Full support</dd><dt><span class="bc-supports-no bc-supports">
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<abbr class="bc-level bc-level-no only-icon" title="No support">
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<span>No support</span>
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</abbr></span></dt><dd>No support</dd><dt><span class="bc-supports-unknown bc-supports">
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<abbr class="bc-level bc-level-unknown only-icon" title="Compatibility unknown">
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<span>Compatibility unknown</span>
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</abbr></span></dt><dd>Compatibility unknown</dd><dt><abbr class="only-icon" title="User must explicitly enable this feature."><span>User must explicitly enable this feature.</span><i class="ic-disabled"></i></abbr></dt><dd>User must explicitly enable this feature.</dd></dl></section></div></div>
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<div id="compat-desktop"> </div>
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<h2 id="相关链接">相关链接</h2>
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<ul>
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<li><a href="Reference/Global_Objects/Object/getOwnPropertyDescriptor" title="Object.getOwnPropertyDescriptor() 方法返回指定对象上一个自有属性对应的属性描述符。（自有属性指的是直接赋予该对象的属性，不需要从原型链上进行查找的属性）"><code>Object.getOwnPropertyDescriptor()</code></a></li>
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<li><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></li>
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<li><a class="external" href="https://github.com/tc39/proposal-object-getownpropertydescriptors" rel="noopener">Polyfill</a></li>
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</ul>
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</article> |