The SharedArrayBuffer.prototype property represents the prototype for the SharedArrayBuffer object.

Property attributes of SharedArrayBuffer.prototype
Writable no
Enumerable no
Configurable no


SharedArrayBuffer instances inherit from SharedArrayBuffer.prototype. As with all constructors, you can change the constructor's prototype object to make changes to all SharedArrayBuffer instances.


Specifies the function that creates an object's prototype. The initial value is the standard built-in SharedArrayBuffer constructor.
SharedArrayBuffer.prototype.byteLength Read only
The size, in bytes, of the array. This is established when the array is constructed and cannot be changed. Read only.


SharedArrayBuffer.prototype.slice(begin, end)
Returns a new SharedArrayBuffer whose contents are a copy of this SharedArrayBuffer's bytes from begin, inclusive, up to end, exclusive. If either begin or end is negative, it refers to an index from the end of the array, as opposed to from the beginning.


Specification Status Comment
ECMAScript Latest Draft (ECMA-262)
The definition of 'SharedArrayBuffer.prototype' in that specification.
Living Standard Initial definition in ES2017.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support6016


46 — 541

No No10.1
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support6060 ?


46 — 541

No No No

1. From version 46 until version 54 (exclusive): this feature is behind the javascript.options.shared_memory preference (needs to be set to true). To change preferences in Firefox, visit about:config.

See also

Document Tags and Contributors

 Contributors to this page: fscholz, lth
 Last updated by: fscholz,