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

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 Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of '%TypedArray%.prototype.keys()' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of '%TypedArray%.prototype.keys()' in that specification.
Draft  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes Yes37 No No10
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support No Yes Yes37 No10 ?

See also

Document Tags and Contributors

 Contributors to this page: wbamberg, fscholz, kdex, David_Gilbertson, eduardoboucas, arai
 Last updated by: wbamberg,