Array.prototype.keys()

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。

語法

arr.keys()

回傳值

一個新的 Array 迭代器（iterator）物件。

範例

鍵迭代器不會乎略陣列中的空元素

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

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Array.prototype.keys' in that specification.		 Standard Initial definition.
ECMAScript (ECMA-262)
The definition of 'Array.prototype.keys' in that specification.		 Living Standard  

瀏覽器相容性

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
keysChrome Full support 38Edge Full support 12Firefox Full support 28IE No support NoOpera Full support 25Safari Full support 8WebView Android Full support 38Chrome Android Full support 38Firefox Android Full support 28Opera Android Full support 25Safari iOS Full support 8Samsung Internet Android Full support 3.0nodejs Full support 0.12

Legend

Full support  
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No support  
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參見

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