ArrayBuffer.prototype.resize()

Baseline 2024
Newly available

Since July 2024, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

The resize() method of ArrayBuffer instances resizes the ArrayBuffer to the specified size, in bytes.

Try it

const buffer = new ArrayBuffer(8, { maxByteLength: 16 });

console.log(buffer.byteLength);
// Expected output: 8

buffer.resize(12);

console.log(buffer.byteLength);
// Expected output: 12

Syntax

js
resize(newLength)

Parameters

newLength

The new length, in bytes, to resize the ArrayBuffer to.

Return value

None (undefined).

Exceptions

TypeError

Thrown if the ArrayBuffer is detached or is not resizable.

RangeError

Thrown if newLength is larger than the maxByteLength of the ArrayBuffer.

Description

The resize() method resizes an ArrayBuffer to the size specified by the newLength parameter, provided that the ArrayBuffer is resizable and the new size is less than or equal to the maxByteLength of the ArrayBuffer. New bytes are initialized to 0.

Note that you can use resize() to shrink as well as grow an ArrayBuffer — it is permissible for newLength to be smaller than the ArrayBuffer's current byteLength.

Examples

Using resize()

In this example, we create a 8-byte buffer that is resizable to a max length of 16 bytes, then check its resizable property, resizing it if resizable returns true:

js
const buffer = new ArrayBuffer(8, { maxByteLength: 16 });

if (buffer.resizable) {
  console.log("Buffer is resizable!");
  buffer.resize(12);
}

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-arraybuffer.prototype.resize

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
resize

Legend

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Full support
Full support
No support
No support

See also