From 218934fa2ed1c702a6d3923d2aa2cc6b43c48684 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:43:23 -0500 Subject: initial commit --- .../reference/global_objects/array/keys/index.html | 76 ++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 files/zh-tw/web/javascript/reference/global_objects/array/keys/index.html (limited to 'files/zh-tw/web/javascript/reference/global_objects/array/keys/index.html') diff --git a/files/zh-tw/web/javascript/reference/global_objects/array/keys/index.html b/files/zh-tw/web/javascript/reference/global_objects/array/keys/index.html new file mode 100644 index 0000000000..fa71299ecb --- /dev/null +++ b/files/zh-tw/web/javascript/reference/global_objects/array/keys/index.html @@ -0,0 +1,76 @@ +--- +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 +--- +
{{JSRef}}
+ +

keys() 方法會回傳一個包含陣列中的每一個索引之鍵(keys)的新 Array Iterator 物件。

+ +
{{EmbedInteractiveExample("pages/js/array-keys.html")}}
+ + + +

語法

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arr.keys()
+ +

回傳值

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一個新的 {{jsxref("Array")}} 迭代器(iterator)物件。

+ +

範例

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鍵迭代器不會乎略陣列中的空元素

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var arr = ['a', , 'c'];
+var sparseKeys = Object.keys(arr);
+var denseKeys = [...arr.keys()];
+console.log(sparseKeys); // ['0', '2']
+console.log(denseKeys);  // [0, 1, 2]
+
+ +

規範

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-array.prototype.keys', 'Array.prototype.keys')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-array.prototype.keys', 'Array.prototype.keys')}}{{Spec2('ESDraft')}} 
+ +

瀏覽器相容性

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+ + +

{{Compat("javascript.builtins.Array.keys")}}

+
+ +

參見

+ + -- cgit v1.2.3-54-g00ecf