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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/array/keys | |
| 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/array/keys')
| -rw-r--r-- | files/zh-cn/web/javascript/reference/global_objects/array/keys/index.html | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/files/zh-cn/web/javascript/reference/global_objects/array/keys/index.html b/files/zh-cn/web/javascript/reference/global_objects/array/keys/index.html new file mode 100644 index 0000000000..6da9228ed2 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/array/keys/index.html @@ -0,0 +1,77 @@ +--- +title: Array.prototype.keys() +slug: Web/JavaScript/Reference/Global_Objects/Array/keys +tags: + - Array + - ECMAScript 2015 + - Iterator + - JavaScript + - Method + - Prototype +translation_of: Web/JavaScript/Reference/Global_Objects/Array/keys +--- +<div>{{JSRef}}</div> + +<p> <code><strong>keys() </strong></code>方法返回一个包含数组中每个索引键的<code><strong>Array Iterator</strong></code>对象。</p> + +<div>{{EmbedInteractiveExample("pages/js/array-keys.html")}}</div> + +<h2 id="Syntax" name="Syntax">语法</h2> + +<pre class="syntaxbox"><code><var>arr</var>.keys()</code> +</pre> + +<h3 id="返回值">返回值 </h3> + +<p>一个新的 {{jsxref("Array")}} 迭代器对象。</p> + +<h2 id="Examples" name="Examples">示例</h2> + +<h3 id="索引迭代器会包含那些没有对应元素的索引">索引迭代器会包含那些没有对应元素的索引</h3> + +<pre class="brush: js">var arr = ["a", , "c"]; +var sparseKeys = Object.keys(arr); +var denseKeys = [...arr.keys()]; +console.log(sparseKeys); // ['0', '2'] +console.log(denseKeys); // [0, 1, 2] +</pre> + +<h2 id="Specifications" name="Specifications">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-array.prototype.keys', 'Array.prototype.keys')}}</td> + <td>{{Spec2('ES2015')}}</td> + <td>Initial definition.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-array.prototype.keys', 'Array.prototype.keys')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility" name="Browser_compatibility">浏览器兼容性</h2> + +<div> +<div> + + +<p>{{Compat("javascript.builtins.Array.keys")}}</p> +</div> +</div> + +<h2 id="See_also" name="See_also">相关链接</h2> + +<ul> + <li>{{jsxref("Array.prototype.values()")}}</li> + <li>{{jsxref("Array.prototype.entries()")}}</li> + <li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols">Iteration protocols</a></li> +</ul> |
