Web/JavaScript/Reference/Global objects/TypedArray/keys

The keys() method returns a new array iterator object that contains the keys for each index in the array.

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Syntax

arr.keys()

Return value

A new array iterator object.

Examples

Iteration using for...of loop

var arr = new Uint8Array([10, 20, 30, 40, 50]);
var eArray = arr.keys();
// your browser must support for..of loop
// and let-scoped variables in for loops
for (let n of eArray) {
  console.log(n);
}

Alternative iteration

var arr = new Uint8Array([10, 20, 30, 40, 50]);
var eArr = arr.keys();
console.log(eArr.next().value); // 0
console.log(eArr.next().value); // 1
console.log(eArr.next().value); // 2
console.log(eArr.next().value); // 3
console.log(eArr.next().value); // 4

Specifications

Specification
[(ECMA-262)The definition of '%TypedArray%.prototype.keys()' in that specification.]

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
keys	Chrome Full support 38	Edge Full support 14	Firefox Full support 37	IE No support No	Opera Full support 25	Safari Full support 10	WebView Android Full support 38	Chrome Android Full support 38	Firefox Android Full support 37	Opera Android Full support 25	Safari iOS Full support 10	Samsung Internet Android Full support 3.0	nodejs Full support 0.12

Legend

Full support  

Full support

No support  

No support

See also

• JavaScript typed arrays
• TypedArray
• TypedArray.prototype.entries()
• TypedArray.prototype.values()
• TypedArray.prototype[@@iterator]()
• for...of
• Iteration protocols

TypedArray.prototype.keys() by Mozilla Contributors is licensed under CC-BY-SA 2.5.