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 Interface
The definition of 'grow()' in that specification.
Working Draft Initial draft definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung InternetNode.js
Basic supportChrome Full support 57Edge Full support 16Firefox Full support 52
Notes
Full support 52
Notes
Notes Disabled in the Firefox 52 Extended Support Release (ESR).
IE No support NoOpera Full support 44Safari Full support 11WebView Android Full support 57Chrome Android Full support 57Edge Mobile Full support Yes
Disabled
Full support Yes
Disabled
Disabled This feature is behind the Experimental JavaScript Features preference.
Firefox Android Full support 52
Notes
Full support 52
Notes
Notes Disabled in the Firefox 52 Extended Support Release (ESR).
Opera Android ? Safari iOS Full support 11Samsung Internet Android Full support 7.0nodejs Full support 8.0.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
See implementation notes.
See implementation notes.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also

Document Tags and Contributors

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