WebAssembly.Memory.prototype.grow()

The grow() protoype method of the Memory object increases the size of the memory instance by a specified number of WebAssembly pages.

Syntax

memory.grow(number);

Parameters

number
The number of WebAssembly pages you want to grow the memory by (each one is 64KiB in size).

Return value

The previous size of the memory, in units of WebAssembly pages.

Examples

The following example creates a new WebAssembly Memory instance with an initial size of 1 page (64KiB), and a maximum size of 10 pages (640KiB).

var memory = new WebAssembly.Memory({initial:1, maximum:10});

We can then grow the instance by one page like so:

const bytesPerPage = 64 * 1024;
console.log(memory.buffer.byteLength / bytesPerPage);  // "1"
console.log(memory.grow(1));                           // "1"
console.log(memory.buffer.byteLength / bytesPerPage);  // "2"

Note the return value of grow() here is the previous number of WebAssembly pages.

Specifications

Specification Status Comment
WebAssembly JavaScript API
The definition of 'grow()' in that specification.
Draft Initial draft definition.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support5716522 No4411
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support5757 Yes1522 No ?11

1. This feature is behind the Experimental JavaScript Features preference.

2. Disabled in the Firefox 52 Extended Support Release (ESR).

See also

Document Tags and Contributors

 Contributors to this page: chrisdavidmills, fscholz, lukewagner
 Last updated by: chrisdavidmills,