uTools-Manuals/docs/javascript/Reference/Global_Objects/Symbol/@@toPrimitive.html

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<p><code><strong>[@@toPrimitive]()</strong></code> 方法可将 Symbol 对象转换为原始值。</p>
<h2 id="语法">语法</h2>
<pre><code class="language-javascript"><var>Symbol()[Symbol.toPrimitive](hint);
</var></code></pre>
<h3 id="返回值">返回值</h3>
<p>该原始值为指定的 <a href="Reference/Global_Objects/Symbol" title='Symbol()函数会返回symbol类型的值，该类型具有静态属性和静态方法。它的静态属性会暴露几个内建的成员对象；它的静态方法会暴露全局的symbol注册，且类似于内建对象类，但作为构造函数来说它并不完整，因为它不支持语法："new Symbol()"。'><code>Symbol</code></a> 对象</p>
<h2 id="描述">描述</h2>
<p> <a href="Reference/Global_Objects/Symbol" title='Symbol()函数会返回symbol类型的值，该类型具有静态属性和静态方法。它的静态属性会暴露几个内建的成员对象；它的静态方法会暴露全局的symbol注册，且类似于内建对象类，但作为构造函数来说它并不完整，因为它不支持语法："new Symbol()"。'><code>Symbol</code></a> 的 <code>[@@toPrimitive]() 方法</code>返回该 Symbol 对象原始值作为 Symbol 数据形式。 <code>hint</code> 参数未被使用。</p>
<p>JavaScript 调用 <code>[@@toPrimitive]() </code>方法将一个对象转换为原始值表示。你不需要自己调用 <code>[@@toPrimitive]()</code> 方法；当对象需要被转换为原始值时，JavaScript 会自动地调用该方法。</p>
<h2 id="规范">规范</h2>
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<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
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<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-symbol.prototype-@@toprimitive" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Symbol.prototype.@@toPrimitive</small></a></td>
<td><span class="spec-Standard">Standard</span></td>
<td>Initial definition.</td>
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<tr>
<td><a class="external" href="https://tc39.github.io/ecma262/#sec-symbol.prototype-@@toprimitive" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">Symbol.prototype.@@toPrimitive</small></a></td>
<td><span class="spec-Draft">Draft</span></td>
<td> </td>
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</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>
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<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
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<td>Basic support</td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><a href="/en-US/Firefox/Releases/44" title="Released on 2016-01-26.">44.0</a> (44.0)</td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
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</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for 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: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td>44.0 (44.0)</td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
<td><span style="color: rgb(255, 153, 0);" title="Compatibility unknown; please update this.">?</span></td>
</tr>
</tbody>
</table>
</div>
<h2 id="参考资料">参考资料</h2>
<ul>
<li><a href="Reference/Global_Objects/Symbol/toPrimitive" title="Symbol.toPrimitive 指将被调用的指定函数值的属性转换为相对应的原始值。"><code>Symbol.toPrimitive</code></a></li>
</ul>
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