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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.
Draft Initial definition in ES2017.

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support No support 55 (55) [1] No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 55.0 (55) [1] No support No support No support

[1] In Firefox version 46 until version 54, this feature is disabled by a preference setting. In about:config, set javascript.options.shared_memory to true

See also

Document Tags and Contributors

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