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diff --git a/files/zh-cn/web/javascript/reference/global_objects/weakmap/get/index.html b/files/zh-cn/web/javascript/reference/global_objects/weakmap/get/index.html new file mode 100644 index 0000000000..5dd596c3ff --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/weakmap/get/index.html @@ -0,0 +1,120 @@ +--- +title: WeakMap.prototype.get() +slug: Web/JavaScript/Reference/Global_Objects/WeakMap/get +translation_of: Web/JavaScript/Reference/Global_Objects/WeakMap/get +--- +<div>{{JSRef}}</div> + +<p><code><strong>get()</strong></code> 方法返回 <code>WeakMap</code> 指定的元素。</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox"><code><em>wm</em>.get(key);</code></pre> + +<h3 id="参数">参数</h3> + +<dl> + <dt>key</dt> + <dd>必须。 想要从 <code>WeakMap </code>获取的元素的键。</dd> +</dl> + +<h3 id="返回值">返回值</h3> + +<h3 id="返回与指定键相关联的值,如果_WeakMap_对象找不到这个键则返回_undefined。"><span style="font-size: 14px; line-height: 1.5;">返回与指定键相关联的值,如果 </span><code style="font-size: 14px; font-style: normal; font-weight: normal; line-height: 1.5;">WeakMap</code><span style="font-size: 14px; line-height: 1.5;"> 对象找不到这个键则返回 </span><code style="font-size: 14px; font-style: normal; font-weight: normal; line-height: 1.5;">undefined</code><span style="font-size: 14px; line-height: 1.5;">。</span></h3> + +<h2 id="例子">例子</h2> + +<h3 id="使用_get_方法">使用 <code>get </code>方法<code> </code></h3> + +<pre class="brush: js">var wm = new WeakMap(); +wm.set(window, "foo"); + +wm.get(window); // 返回 "foo". +wm.get("baz"); // 返回 undefined. +</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>{{SpecName('ES6', '#sec-weakmap.prototype.get', 'WeakMap.prototype.get')}}</td> + <td>{{Spec2('ES6')}}</td> + <td>Initial definition.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-weakmap.prototype.get', 'WeakMap.prototype.get')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + +<p>{{CompatibilityTable}}</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>{{CompatGeckoDesktop("6.0")}}</td> + <td>11</td> + <td>23</td> + <td>7.1</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>{{CompatNo}}</td> + <td>{{CompatGeckoMobile("6.0")}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatNo}}</td> + <td>8</td> + </tr> + </tbody> +</table> +</div> + +<h2 id="Firefox_中的注意事项">Firefox 中的注意事项</h2> + +<ul> + <li>Prior to SpiderMonkey 38 {{geckoRelease(38)}}, this method threw a {{jsxref("TypeError")}} when the key parameter was not an object. However, the latest ES6 standard specifies to return <code>undefined</code> instead. Furthermore, <code>WeakMap.prototype.get</code> accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher ({{bug(1127827)}}).</li> +</ul> + +<h2 id="相关链接">相关链接</h2> + +<ul> + <li>{{jsxref("WeakMap")}}</li> + <li>{{jsxref("WeakMap.set()")}}</li> + <li>{{jsxref("WeakMap.has()")}}</li> +</ul> |