TypedArray.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 ⁨September 2016⁩.

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The keys() method of TypedArray instances returns a new array iterator object that contains the keys for each index in the typed array. This method has the same algorithm as Array.prototype.keys().

Try it

const uint8 = new Uint8Array([10, 20, 30, 40, 50]);
const keys = uint8.keys();

keys.next();
keys.next();

console.log(keys.next().value);
// Expected output: 2

Syntax

js
keys()

Parameters

None.

Return value

A new iterable iterator object.

Description

See Array.prototype.keys() for more details. This method is not generic and can only be called on typed array instances.

Examples

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Iteration using for...of loop

js
const arr = new Uint8Array([10, 20, 30, 40, 50]);
const arrKeys = arr.keys();
for (const n of arrKeys) {
  console.log(n);
}

Alternative iteration

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

Specifications

Specification
ECMAScript® 2026 Language Specification>
# sec-%typedarray%.prototype.keys>

Browser compatibility

See also