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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/javascript/reference/global_objects/map/@@species/index.html | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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diff --git a/files/zh-cn/web/javascript/reference/global_objects/map/@@species/index.html b/files/zh-cn/web/javascript/reference/global_objects/map/@@species/index.html new file mode 100644 index 0000000000..ded2acd30b --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/map/@@species/index.html @@ -0,0 +1,67 @@ +--- +title: 'get Map[@@species]' +slug: Web/JavaScript/Reference/Global_Objects/Map/@@species +translation_of: Web/JavaScript/Reference/Global_Objects/Map/@@species +--- +<div>{{JSRef}}</div> + +<p> <code><strong>Map[@@species]</strong></code> 访问器属性会返回一个 <code>Map</code> 构造函数.</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox">Map[Symbol.species] +</pre> + +<h2 id="描述">描述</h2> + +<p>The species accessor property returns the default constructor for <code>Map</code> objects. Subclass constructors may over-ride it to change the constructor assignment.</p> + +<h2 id="案例">案例</h2> + +<p>The species property returns the default constructor function, which is the <code>Map</code> constructor for <code>Map</code> objects:</p> + +<pre class="brush: js">Map[Symbol.species]; // function Map()</pre> + +<p>In a derived collection object (e.g. your custom map <code>MyMap</code>), the <code>MyMap</code> species is the <code>MyMap</code> constructor. However, you might want to overwrite this, in order to return parent <code>Map</code> objects in your derived class methods:</p> + +<pre class="brush: js">class MyMap extends Map { + // 重写覆盖 MyMap species to the parent Map constructor + static get [Symbol.species]() { return Map; } +}</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('ES2015', '#sec-get-map-@@species', 'get Map [ @@species ]')}}</td> + <td>{{Spec2('ES2015')}}</td> + <td>Initial definition.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-get-map-@@species', 'get Map [ @@species ]')}}</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> + +<div> + + +<p>{{Compat("javascript.builtins.Map.@@species")}}</p> +</div> + +<h2 id="相关链接">相关链接</h2> + +<ul> + <li>{{jsxref("Map")}}</li> + <li>{{jsxref("Symbol.species")}}</li> +</ul> |