ArrayBuffer.transfer()

The static ArrayBuffer.transfer() method returns a new ArrayBuffer whose contents are taken from the oldBuffer's data and then is either truncated or zero-extended by newByteLength. If newByteLength is undefined, the byteLength of the oldBuffer is used. This operation leaves oldBuffer in a detached state.

Syntax

ArrayBuffer.transfer(oldBuffer [, newByteLength]);

Parameters

oldBuffer

An ArrayBuffer object from which to transfer from.

newByteLength

The byte length of the new ArrayBuffer object.

Description

The ArrayBuffer.transfer() method allows you to grow and detach ArrayBuffer objects. The ability to grow an ArrayBuffer without copying has the advantage of being much faster for large buffers (similar to realloc). The ability to detach an ArrayBuffer gives the developer explicit control over when the underlying memory is released.  This avoids having to drop all references and wait for garbage collection.

Examples

var buf1 = new ArrayBuffer(40);
new Int32Array(buf1)[0] = 42;

var buf2 = ArrayBuffer.transfer(buf1, 80);
buf1.byteLength; // 0
buf2.byteLength; // 80
new Int32Array(buf2)[0]; // 42

var buf3 = ArrayBuffer.transfer(buf2, 0);
buf2.byteLength; // 0
buf3.byteLength; // 0

Specifications

Not part of any current specification draft document, but has been proposed for a future ECMA-262 edition.

Browser compatibility

See also

• JavaScript typed arrays