2019-04-21 11:50:48 +08:00

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<article id="wikiArticle">
<div></div>
<p><code><strong>add()</strong></code> 方法在 <code>WeakSet</code> 对象的最后一个元素后添加新的对象。</p>
<h2 id="语法">语法</h2>
<pre><code class="language-javascript"><code><em>ws</em>.add(value);</code>
</code></pre>
<h3 id="参数">参数</h3>
<dl>
<dt>value</dt>
<dd>必须。 将对象添加进 <code>WeakSet</code> 集合中。</dd>
</dl>
<h3 id="返回值">返回值</h3>
<p><code>WeakSet</code> 对象。</p>
<h2 id="使用_add_方法">使用 <code>add</code> 方法</h2>
<pre><code class="language-javascript">var ws = new WeakSet();
ws.add(window); // 添加 window 对象进 WeakSet 中
ws.has(window); // true
// Weakset 仅取得对象作为参数
ws.add(1);
// 结果为 "TypeError: Invalid value used in weak set" 在 Chrome 浏览器中
// 并且 "TypeError: 1 is not a non-null object" 在 Firefox 浏览器中</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-weakset.prototype.add" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">WeakSet.prototype.add</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-weakset.prototype.add" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">WeakSet.prototype.add</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>
<p></p><div class="blockIndicator warning"><strong><a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">We're converting our compatibility data into a machine-readable JSON format</a></strong>.
This compatibility table still uses the old format,
because we haven't yet converted the data it contains.
<strong><a class="new" href="/zh-CN/docs/MDN/Contribute/Structures/Compatibility_tables" rel="nofollow">Find out how you can help!</a></strong></div>
<div class="htab">
<a id="AutoCompatibilityTable" name="AutoCompatibilityTable"></a>
<ul>
<li class="selected"><a>Desktop</a></li>
<li><a>Mobile</a></li>
</ul>
</div><p></p>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td>36</td>
<td><a href="/en-US/Firefox/Releases/34" title="Released on 2014-12-01.">34</a> (34)</td>
<td><span style="color: #f00;">未实现</span></td>
<td>23</td>
<td><span style="color: #f00;">未实现</span></td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td><span style="color: #f00;">未实现</span></td>
<td>34.0 (34)</td>
<td><span style="color: #f00;">未实现</span></td>
<td><span style="color: #f00;">未实现</span></td>
<td><span style="color: #f00;">未实现</span></td>
</tr>
</tbody>
</table>
</div>
<h2 id="相关链接">相关链接</h2>
<ul>
<li><a href="Reference/Global_Objects/WeakSet" title="WeakSet 对象允许你将弱保持对象存储在一个集合中。"><code>WeakSet</code></a></li>
<li><a href="Reference/Global_Objects/WeakSet/delete" title="delete() 方法从 WeakSet 对象中移除指定的元素。"><code>WeakSet.prototype.delete()</code></a></li>
<li><a href="Reference/Global_Objects/WeakSet/has" title="has() 方法根据 WeakSet 是否存在相应对象返回布尔值。"><code>WeakSet.prototype.has()</code></a></li>
</ul>
</article>