SharedArrayBuffer.prototype.growable

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 growable accessor property of SharedArrayBuffer instances returns whether this SharedArrayBuffer can be grow or not.

Description

The growable 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. If a maxByteLength option was set in the constructor, growable will return true; if not, it will return false.

Examples

Using growable

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

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

if (buffer.growable) {
  console.log("SAB is growable!");
  buffer.grow(12);
}

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-get-sharedarraybuffer.prototype.growable

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
growable

Legend

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Full support
Full support
No support
No support

See also