Allocate a buffer from an ArrayBuffer.
npm install @stdlib/buffer-from-arraybufferWe believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js. The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases. When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there. To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
About stdlib...
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Allocate a [buffer][@stdlib/buffer/ctor] from an [ArrayBuffer][@stdlib/array/buffer].
``bash`
npm install @stdlib/buffer-from-arraybuffer
`javascript`
var arraybuffer2buffer = require( '@stdlib/buffer-from-arraybuffer' );
#### arraybuffer2buffer( buf\[, byteOffset\[, length]] )
Allocates a [buffer][@stdlib/buffer/ctor] from an [ArrayBuffer][@stdlib/array/buffer].
`javascript
var ArrayBuffer = require( '@stdlib/array-buffer' );
var ab = new ArrayBuffer( 10 );
var buf = arraybuffer2buffer( ab );
// returns
`
By default, the function allocates a [buffer][@stdlib/buffer/ctor] starting from the first byte of the provided [ArrayBuffer][@stdlib/array/buffer]. To specify an alternative starting index, provide a byteOffset.
`javascript
var ArrayBuffer = require( '@stdlib/array-buffer' );
var ab = new ArrayBuffer( 10 );
var buf = arraybuffer2buffer( ab, 2 );
// returns
var len = buf.length;
// returns 8
`
By default, the function allocates a [buffer][@stdlib/buffer/ctor] until the end of the provided [ArrayBuffer][@stdlib/array/buffer]. To allocate a specified number of [ArrayBuffer][@stdlib/array/buffer] bytes, provide a length.
`javascript
var ArrayBuffer = require( '@stdlib/array-buffer' );
var ab = new ArrayBuffer( 10 );
var buf = arraybuffer2buffer( ab, 2, 4 );
// returns
var len = buf.length;
// returns 4
`
The behavior of this function varies across Node.js versions due to changes in the underlying Node.js APIs:
- <3.0.0: the function copies [ArrayBuffer][@stdlib/array/buffer] bytes to a new [Buffer][@stdlib/buffer/ctor] instance.>=3.0.0
- and <5.10.0: if provided a byteOffset, the function copies [ArrayBuffer][@stdlib/array/buffer] bytes to a new [Buffer][@stdlib/buffer/ctor] instance; otherwise, the function returns a view of an [ArrayBuffer][@stdlib/array/buffer] without copying the underlying memory.<6.0.0
- : if provided an empty [ArrayBuffer][@stdlib/array/buffer], the function returns an empty [Buffer][@stdlib/buffer/ctor] which is not an [ArrayBuffer][@stdlib/array/buffer] view.>=6.0.0
- : the function returns a view of an [ArrayBuffer][@stdlib/array/buffer] without copying the underlying memory.
`javascript
var ArrayBuffer = require( '@stdlib/array-buffer' );
var Float64Array = require( '@stdlib/array-float64' );
var randu = require( '@stdlib/random-base-randu' );
var IS_LITTLE_ENDIAN = require( '@stdlib/assert-is-little-endian' );
var arraybuffer2buffer = require( '@stdlib/buffer-from-arraybuffer' );
var high;
var view;
var low;
var buf;
var ab;
var i;
// Allocate an ArrayBuffer:
ab = new ArrayBuffer( 64 );
// Create a Float64 view and set random values:
view = new Float64Array( ab );
for ( i = 0; i < view.length; i++ ) {
view[ i ] = randu();
}
// Create a new buffer from the ArrayBuffer:
buf = arraybuffer2buffer( ab );
// Read the high and low words for each double:
for ( i = 0; i < view.length; i++ ) {
if ( IS_LITTLE_ENDIAN ) {
high = buf.readUInt32LE( (8*i)+4 );
low = buf.readUInt32LE( 8*i );
} else {
high = buf.readUInt32BE( 8*i );
low = buf.readUInt32BE( (8*i)+4 );
}
console.log( 'Value: %d. High: %d. Low: %d.', view[ i ], high, low );
}
`
*
- [@stdlib/buffer-ctor][@stdlib/buffer/ctor]: Buffer.
- [@stdlib/buffer-from-array][@stdlib/buffer/from-array]: allocate a buffer using an octet array.
- [@stdlib/buffer-from-buffer][@stdlib/buffer/from-buffer]: copy buffer data to a new Buffer instance.
- [@stdlib/buffer-from-string][@stdlib/buffer/from-string]: allocate a buffer containing a provided string.
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/buffer-from-arraybuffer.svg
[npm-url]: https://npmjs.org/package/@stdlib/buffer-from-arraybuffer
[test-image]: https://github.com/stdlib-js/buffer-from-arraybuffer/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/buffer-from-arraybuffer/actions/workflows/test.yml?query=branch:v0.2.3
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/buffer-from-arraybuffer/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/buffer-from-arraybuffer?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/buffer-from-arraybuffer/tree/deno
[deno-readme]: https://github.com/stdlib-js/buffer-from-arraybuffer/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/buffer-from-arraybuffer/tree/umd
[umd-readme]: https://github.com/stdlib-js/buffer-from-arraybuffer/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/buffer-from-arraybuffer/tree/esm
[esm-readme]: https://github.com/stdlib-js/buffer-from-arraybuffer/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/buffer-from-arraybuffer/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/buffer-from-arraybuffer/main/LICENSE
[@stdlib/array/buffer]: https://www.npmjs.com/package/@stdlib/array-buffer
[@stdlib/buffer/ctor]: https://www.npmjs.com/package/@stdlib/buffer-ctor
[@stdlib/buffer/from-array]: https://www.npmjs.com/package/@stdlib/buffer-from-array
[@stdlib/buffer/from-buffer]: https://www.npmjs.com/package/@stdlib/buffer-from-buffer
[@stdlib/buffer/from-string]: https://www.npmjs.com/package/@stdlib/buffer-from-string