Uint8Array

Summary

The Uint8Array typed array represents an 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

Uint8Array(length);
Uint8Array(typedArray);
Uint8Array(object);
Uint8Array(buffer [, byteOffset [, length]]);

For more information about the constructor syntax and the parameters, see TypedArray.

Properties

Uint8Array.BYTES_PER_ELEMENT

Returns a number value of the element size. 1 in the case of an Uint8Array.

Uint8Array.length

Length property whose value is 3.

Uint8Array.name

Returns the string value of the constructor name. In the case of the Uint8Array type: "Uint8Array".

Uint8Array.prototype

Prototype for the TypedArray objects.

Methods

Uint8Array.from()

See Array.from(). Not implemented, see bug 896608.

Uint8Array.of()

See Array.of(). Not implemented, see bug 896608.

Uint8Array prototype

All Uint8Array objects inherit from %TypedArray%.prototype.

Properties

Uint8Array.prototype.constructor

Returns the function that created an instance's prototype. This is the Uint8Array constructor by default.

Uint8Array.prototype.buffer Read only

Returns the ArrayBuffer referenced by the Uint8Array Fixed at construction time and thus read only.

Uint8Array.prototype.byteLength Read only

Returns the length (in bytes) of the Uint8Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.

Uint8Array.prototype.byteOffset Read only

Returns the offset (in bytes) of the Uint8Array from the start of its ArrayBuffer. Fixed at construction time and thus read only.

Uint8Array.prototype.length Read only

Returns the number of elements hold in the Uint8Array. Fixed at construction time and thus read only.

Methods

Uint8Array.prototype.copyWithin()

See Array.prototype.copyWithin().

Uint8Array.prototype.move() Unimplemented

Former non-standard version of Uint8Array.prototype.copyWithin().

Uint8Array.prototype.set()

Stores multiple values in the Uint8Array, reading input values from a specified array.

Uint8Array.prototype.subarray()

Returns a new Uint8Array from the given start and end element index.

Examples

// From a length
var 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
var arr = new Uint8Array([21,31]);
console.log(arr[1]); // 31

// From another TypedArray
var x = new Uint8Array([21, 31]);
var y = new Uint8Array(x);
console.log(y[0]); // 21

// From an ArrayBuffer
var buffer = new ArrayBuffer(8);
var z = Uint8Array(buffer, 1, 4);

Specifications

Browser compatibility

See also

• JavaScript typed arrays
• ArrayBuffer
• DataView