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diff --git a/files/zh-cn/conflicting/web/javascript/reference/statements/switch/index.html b/files/zh-cn/conflicting/web/javascript/reference/statements/switch/index.html new file mode 100644 index 0000000000..12e076166c --- /dev/null +++ b/files/zh-cn/conflicting/web/javascript/reference/statements/switch/index.html @@ -0,0 +1,120 @@ +--- +title: default +slug: Web/JavaScript/Reference/Statements/default +tags: + - JavaScript + - Keyword +translation_of: Web/JavaScript/Reference/Statements/switch +translation_of_original: Web/JavaScript/Reference/Statements/default +--- +<div>{{jsSidebar("Statements")}}</div> + +<div></div> + +<p><strong>default 关键字</strong>可以在 JavaScript 的两种情况下使用:在 {{jsxref("Statements/switch", "switch")}} ,或 {{jsxref("Statements/export", "export")}} 中。</p> + +<h2 id="语法">语法</h2> + +<p>在{{jsxref("Statements/switch", "switch")}} 语句中使用:</p> + +<pre class="syntaxbox">switch (expression) { + case value1: + //当表达式的值和value1匹配执行这里的语句 + [break;] + default: + //当表达式的值没有匹配,执行这里的语句 + [break;] +}</pre> + +<p>在{{jsxref("Statements/export", "export")}} 中使用:</p> + +<pre class="syntaxbox">export default <em>nameN</em> </pre> + +<h2 id="描述">描述</h2> + +<p>更多细节,参见</p> + +<ul> + <li>{{jsxref("Statements/switch", "switch")}} 语句和</li> + <li>{{jsxref("Statements/export", "export")}} 语句页面。</li> +</ul> + +<h2 id="示例">示例</h2> + +<h3 id="在switch语句中使用default">在<code>switch</code>语句中使用<code>default</code></h3> + +<p>在以下示例中,如果<code>expr</code>为“Oranges”或“Apples”,程序将匹配“Oranges”或“Apples”的值并执行相应的声明。在任何其它情况下,<code>default</code>关键字将执行关联的语句。</p> + +<pre class="brush: js">switch (expr) { + case "Oranges": + console.log("Oranges are $0.59 a pound."); + break; + case "Apples": + console.log("Apples are $0.32 a pound."); + break; + default: + console.log("Sorry, we are out of " + expr + "."); +}</pre> + +<h3 id="在export语句中使用default">在<code>export</code>语句中使用<code>default</code></h3> + +<p>如果要导出单个值或需要模块的回调值,则可以使用默认导出: </p> + +<pre class="brush: js">// module "my-module.js" +let cube = function cube(x) { + return x * x * x; +} +export default cube; +</pre> + +<p>然后,在另一个脚本中,默认导出将直接被导入:</p> + +<pre class="brush: js">// module "my-module.js" +import myFunction from 'my-module'; +console.log(myFunction(3)); // 27 +</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-switch-statement', 'switch statement')}}</td> + <td>{{Spec2('ES6')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('ES6', '#sec-exports', 'Exports')}}</td> + <td>{{Spec2('ES6')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-switch-statement', 'switch statement')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-exports', 'Exports')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td></td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容">浏览器兼容</h2> + +<div class="hidden">The compatibility table on 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.</div> + +<p>{{Compat("javascript.statements.default")}}</p> + +<h2 id="See_also">See also</h2> + +<ul> + <li>{{jsxref("Statements/export", "export")}}</li> + <li>{{jsxref("Statements/switch", "switch")}}</li> +</ul> |