Uint8Array() constructor

The Uint8Array() constructor creates a typed array of 8-bit unsigned integers. The contents are initialized to 0. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

Syntax

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

See TypedArray.

Exceptions

See TypedArray.

Examples

Different ways to create a Uint8Array

// 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

Specification
ECMAScript Language Specification
# sec-typedarray-constructors

Browser compatibility

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See also