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

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung InternetNode.js
Basic supportChrome Full support YesEdge Full support 14Firefox Full support 37IE No support NoOpera No support NoSafari Full support 10WebView Android No support NoChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 37Opera Android No support NoSafari iOS Full support 10Samsung Internet Android Full support Yesnodejs Full support 0.12

Legend

Full support  
Full support
No support  
No support

See also

Document Tags and Contributors

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