ArrayBuffer.prototype.byteLength

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The byteLength accessor property of ArrayBuffer instances returns the length (in bytes) of this array buffer.

Try it

// Create an ArrayBuffer with a size in bytes
const buffer = new ArrayBuffer(8);

// Use byteLength to check the size
const bytes = buffer.byteLength;

console.log(bytes);
// Expected output: 8

Description

The byteLength property is an accessor property whose set accessor function is undefined, meaning that you can only read this property. The value is established when the array is constructed and cannot be changed. This property returns 0 if this ArrayBuffer has been detached.

Examples

Using byteLength

js
const buffer = new ArrayBuffer(8);
buffer.byteLength; // 8

Specifications

Specification
ECMAScript® 2027 Language Specification
# sec-get-arraybuffer.prototype.bytelength

Browser compatibility

desktop mobile server
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Bun
Deno
Node.js
byteLength
Chrome – Full support
Chrome 7 (Release date: 2010-10-19)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 4 (Release date: 2011-03-22)
footnote Full support
Opera – Full support
Opera 11.6 (Release date: 2011-12-06)
footnote Full support
Safari – Full support
Safari 5.1 (Release date: 2011-07-20)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 4 (Release date: 2011-03-29)
footnote Full support
Opera Android – Full support
Opera Android 12 (Release date: 2012-02-25)
footnote Full support
Safari on iOS – Full support
Safari on iOS 4.2 (Release date: 2010-11-22)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4 (Release date: 2011-10-18)
footnote Full support
WebView on iOS – Full support
WebView on iOS 4.2 (Release date: 2010-11-22)
footnote Full support
Bun – Full support
Bun 1 (Release date: 2023-09-08)
footnote Full support
Deno – Full support
Deno 1 (Release date: 2020-05-13)
footnote Full support
Node.js – Full support
Node.js 0.10 (Release date: 2013-03-11)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support

See also