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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/date/@@toprimitive | |
| parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
| download | translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.gz translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.bz2 translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.zip | |
initial commit
Diffstat (limited to 'files/zh-cn/web/javascript/reference/global_objects/date/@@toprimitive')
| -rw-r--r-- | files/zh-cn/web/javascript/reference/global_objects/date/@@toprimitive/index.html | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/files/zh-cn/web/javascript/reference/global_objects/date/@@toprimitive/index.html b/files/zh-cn/web/javascript/reference/global_objects/date/@@toprimitive/index.html new file mode 100644 index 0000000000..5bf2e177ee --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/date/@@toprimitive/index.html @@ -0,0 +1,61 @@ +--- +title: 'Date.prototype[@@toPrimitive]' +slug: Web/JavaScript/Reference/Global_Objects/Date/@@toPrimitive +translation_of: Web/JavaScript/Reference/Global_Objects/Date/@@toPrimitive +--- +<div>{{JSRef}}</div> + +<p><code><strong>[@@toPrimitive]()</strong></code> 方法可以转换一个 <code>Date</code> 对象到一个原始值。</p> + +<h2 id="用法">用法</h2> + +<pre class="syntaxbox"><var>Date()[Symbol.toPrimitive](hint); +</var></pre> + +<h3 id="返回值">返回值</h3> + +<p>给出的 {{jsxref("Date")}} 的原始值。根据传入参数的不同,可以返回 string 或 number 类型。</p> + +<h2 id="说明">说明</h2> + +<p>{{jsxref("Date")}} 对象的 <code>[@@toPrimitive]()</code> 方法可以返回一个原始值,或是 string,或是number。</p> + +<p>如果 <code>hint</code> 是 <code>"string"</code> 或 <code>"default"</code>,<code>[@@toPrimitive]()</code> 将会调用 {{jsxref("Object.prototype.toString()", "toString")}}。如果 <code>toString</code> 属性不存在,则调用 {{jsxref("Object.prototype.valueOf()", "valueOf")}}。如果 <code>valueOf</code> 也不存在,则抛出一个{{jsxref("TypeError")}}。</p> + +<p>如果 <code>hint</code> 是 <code>"number"</code>,<code>[@@toPrimitive]()</code> 会首先尝试 <code>valueOf</code>,若失败再尝试 <code>toString</code>。</p> + +<p>当期望一个原始值却收到一个对象时,JavaScript 可以自动的调用 <code>[@@toPrimitive]()</code> 方法来将一个对象转化成原始值,所以你很少会需要自己调用这个方法。</p> + +<h2 id="Specifications">Specifications</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-date.prototype-@@toprimitive', 'Date.prototype.@@toPrimitive')}}</td> + <td>{{Spec2('ES6')}}</td> + <td>Initial definition.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-date.prototype-@@toprimitive', 'Date.prototype.@@toPrimitive')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility">Browser compatibility</h2> + +<p class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p> + +<p>{{Compat("javascript.builtins.Date.@@toPrimitive")}}</p> + +<h2 id="See_also">See also</h2> + +<ul> + <li>{{jsxref("Symbol.toPrimitive")}}</li> +</ul> |
