ArrayBuffer

O objeto ArrayBuffer é um tipo de dado usado para representar um genérico, buffer de dados binários de tamanho fixo. Você não pode manipular diretamente os conteúdos de um ArrayBuffer;  em vez disso, você cria um objeto ArrayBufferView que representa o buffer em um formato específico, e usa para ler e escrever os conteúdos do buffer.

Syntax

new ArrayBuffer(length)

Parameters

length

The size, in bytes, of the array buffer to create.

Return value

A new ArrayBuffer object of the specified size. Its contents are initialized to 0.

Exceptions

A RangeError is thrown if the length is larger than Number.MAX_SAFE_INTEGER (>= 2 ** 53) or negative.

Description

The ArrayBuffer constructor creates a new ArrayBuffer of the given length in bytes.

Getting an array buffer from existing data

• From a Base64 string
• From a local file

Properties

ArrayBuffer.length

The ArrayBuffer constructor's length property whose value is 1.

get ArrayBuffer[@@species]

The constructor function that is used to create derived objects.

ArrayBuffer.prototype

Allows the addition of properties to all ArrayBuffer objects.

Methods

ArrayBuffer.isView(arg)

Returns true if arg is one of the ArrayBuffer views, such as typed array objects or a DataView. Returns false otherwise.

ArrayBuffer.transfer(oldBuffer [, newByteLength])

Returns a new ArrayBuffer whose contents are taken from the oldBuffer's data and then is either truncated or zero-extended by newByteLength.

Instances

All ArrayBuffer instances inherit from ArrayBuffer.prototype.

Properties

ArrayBuffer.prototype.constructor

Specifies the function that creates an object's prototype. The initial value is the standard built-in ArrayBuffer constructor.

ArrayBuffer.prototype.byteLength Read only

The size, in bytes, of the array. This is established when the array is constructed and cannot be changed. Read only.

Methods

ArrayBuffer.prototype.slice()

Returns a new ArrayBuffer whose contents are a copy of this ArrayBuffer's bytes from begin, inclusive, up to end, exclusive. If either begin or end is negative, it refers to an index from the end of the array, as opposed to from the beginning.

ArrayBuffer.slice()

Has the same functionality as ArrayBuffer.prototype.slice().

Exemplo

In this example, we create a 8-byte buffer with a Int32Array view referring to the buffer:

var buffer = new ArrayBuffer(8);
var view   = new Int32Array(buffer);

Especificações

Compatibilidade entre Navegadores

Compatibility notes

Starting with ECMAScript 2015, ArrayBuffer constructors require to be constructed with a new operator. Calling an ArrayBuffer constructor as a function without new, will throw a TypeError from now on.

var dv = ArrayBuffer(10); 
// TypedError: calling a builtin ArrayBuffer constructor
// without new is forbidden

var dv = new ArrayBuffer(10);

Veja também

• JavaScript typed arrays
• SharedArrayBuffer