Array.prototype.keys()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since May 2018.

Sumário

O método keys() retorna um novo Array Iterator que contém as chaves para cada index do array.

Sintaxe

arr.keys()

Exemplos

Exemplo: uso básico

js
var arr = ["a", "b", "c"];
var iterator = arr.keys();

console.log(iterator.next()); // { value: 0, done: false }
console.log(iterator.next()); // { value: 1, done: false }
console.log(iterator.next()); // { value: 2, done: false }
console.log(iterator.next()); // { value: undefined, done: true }

Exemplo: keys iterator não ignora lacunas

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

Especificações

Specification
ECMAScript® 2025 Language Specification
# sec-array.prototype.keys

Compatibilidade de Browser

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
keys

Legend

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Full support
Full support

Veja também