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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/statements/import.meta/index.html | |
| parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
| download | translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.gz translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.tar.bz2 translated-content-33058f2b292b3a581333bdfb21b8f671898c5060.zip | |
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diff --git a/files/zh-cn/web/javascript/reference/statements/import.meta/index.html b/files/zh-cn/web/javascript/reference/statements/import.meta/index.html new file mode 100644 index 0000000000..95f5f68e36 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/statements/import.meta/index.html @@ -0,0 +1,104 @@ +--- +title: import.meta +slug: Web/JavaScript/Reference/Statements/import.meta +tags: + - JavaScript + - Language feature + - Modules + - Reference + - Statement + - import +translation_of: Web/JavaScript/Reference/Statements/import.meta +--- +<div>{{JSSidebar("Statements")}}</div> + +<p><code>import.meta</code>是一个给JavaScript模块暴露特定上下文的元数据属性的对象。它包含了这个模块的信息,比如说这个模块的URL。</p> + +<h2 id="语法">语法</h2> + +<pre class="syntaxbox">import.meta</pre> + +<h2 id="描述">描述</h2> + +<p><code>import.meta</code>对象由一个关键字<code>"import"</code>,一个点符号和一个<code>meta</code>属性名组成。通常情况下<code>"import."</code>是作为一个属性访问的上下文,但是在这里<code>"import"</code>不是一个真正的对象。</p> + +<p><code>import.meta</code>对象是由ECMAScript实现的,它带有一个{{jsxref("null")}}的原型对象。这个对象可以扩展,并且它的属性都是可写,可配置和可枚举的。</p> + +<h2 id="示例">示例</h2> + +<p>这里有一个 <code>my-module.mjs模块</code></p> + +<pre class="brush: html"><script type="module" src="my-module.mjs"></script> +</pre> + +<p>你可以通过 <code>import.meta</code> 对象获取这个模块的元数据信息.</p> + +<pre class="brush: js">console.log(import.meta); // { url: "file:///home/user/my-module.mjs" }</pre> + +<p>它返回一个带有<code>url</code>属性的对象,指明模块的基本URL。也可以是外部脚本的URL,还可以是内联脚本所属文档的URL。</p> + +<p>注意,url也可能包含参数或者哈希(比如后缀<code>?</code>或<code>#</code>)</p> + +<p>以下面的HTML为例:</p> + +<pre><script type="module"> +import './index.mjs?someURLInfo=5'; +</script></pre> + +<p>...下面的JavaScript会打印<code>someURLInfo</code>这个参数:</p> + +<pre>// index.mjs +new URL(import.meta.url).searchParams.get('someURLInfo'); // 5</pre> + +<p>在脚本中引入别的脚本同样生效:</p> + +<pre>// index.mjs +import './index2.mjs?someURLInfo=5'; + +// index2.mjs +new URL(import.meta.url).searchParams.get('someURLInfo'); // 5</pre> + +<p>虽然在上述例子中,Node.js允许携带参数(或哈希),但以Node 14.1.0为例,使用<code>node --experimental-modules index.mjs?someURLInfo=5</code> 执行脚本,查询URL参数将会报错(该环境下<code>index.mjs?someURLInfo=5</code> 被视作一个文件而不是URL)</p> + +<p>像这种特定于文件的参数传递可能是对应用范围内<code>location.href</code>(ps: 通过在HTML路径添加参数或哈希)(而在Node.js中是<code>process.env</code>)的补充</p> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">规范</th> + <th scope="col">状态</th> + <th scope="col">备注</th> + </tr> + <tr> + <td><a href="https://github.com/tc39/proposal-import-meta">tc39/proposal-import-meta</a></td> + <td>Stage 3</td> + <td>Initial definition.</td> + </tr> + <tr> + <td><a href="https://html.spec.whatwg.org/multipage/webappapis.html#hostgetimportmetaproperties">HTML Standard</a></td> + <td>Living Standard</td> + <td>Defines import.meta properties in HTML.</td> + </tr> + </tbody> +</table> + +<h2 id="浏览器支持">浏览器支持</h2> + + + +<p>{{Compat("javascript.statements.import_meta")}}</p> + +<h3 id="Implementation_Progress">Implementation Progress</h3> + +<p>The following table provides a daily implementation status for this feature, because this feature has not yet reached cross-browser stability. The data is generated by running the relevant feature tests in <a href="https://github.com/tc39/test262">Test262</a>, the standard test suite of JavaScript, in the nightly build, or latest release of each browser's JavaScript engine.</p> + +<p>{{EmbedTest262ReportResultsTable("import.meta")}}</p> + +<h2 id="See_also">See also</h2> + +<ul> + <li><a href="/en-US/docs/Web/JavaScript/Reference/Statements/import">import</a></li> + <li><code><a href="/en-US/docs/Web/JavaScript/Reference/Statements/export">export</a></code></li> +</ul> |
