W3cubDocs

/JavaScript

Uint8Array() constructor

The Uint8Array() constructor creates Uint8Array objects. The contents are initialized to 0.

Syntax

js
new Uint8Array()
new Uint8Array(length)
new Uint8Array(typedArray)
new Uint8Array(object)

new Uint8Array(buffer)
new Uint8Array(buffer, byteOffset)
new Uint8Array(buffer, byteOffset, length)

Note: Uint8Array() can only be constructed with new. Attempting to call it without new throws a TypeError.

Parameters

Exceptions

Examples

Different ways to create a Uint8Array

js
// From a length
const uint8 = new Uint8Array(2);
uint8[0] = 42;
console.log(uint8[0]); // 42
console.log(uint8.length); // 2
console.log(uint8.BYTES_PER_ELEMENT); // 1

// From an array
const x = new Uint8Array([21, 31]);
console.log(x[1]); // 31

// From another TypedArray
const y = new Uint8Array(x);
console.log(y[0]); // 21

// From an ArrayBuffer
const buffer = new ArrayBuffer(8);
const z = new Uint8Array(buffer, 1, 4);
console.log(z.byteOffset); // 1

// From an iterable
const iterable = (function* () {
  yield* [1, 2, 3];
})();
const uint8FromIterable = new Uint8Array(iterable);
console.log(uint8FromIterable);
// Uint8Array [1, 2, 3]

Specifications

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
Uint8Array 7 12 4 11.6 5.1 18 4 12 4.2 1.0 4 1.0 0.10.0
constructor_without_parameters 7 12 55 11.6 5.1 18 55 12 5 1.0 ≤37 1.0 0.10.0
iterable_allowed 39 14 52 26 10 39 52 26 10 4.0 39 1.0 4.0.0
new_required 7 14 44 15 5.1 18 44 14 5 1.0 ≤37 1.0 0.12.0

See also

© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array/Uint8Array