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The byteLength accessor property represents the length of an SharedArrayBuffer in bytes.




The byteLength 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 shared array is constructed and cannot be changed.


var sab = new SharedArrayBuffer(1024);
sab.byteLength; // 1024


Specification Status Comment
ECMAScript Latest Draft (ECMA-262)
The definition of 'SharedArrayBuffer.prototype.byteLength' 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] Enabled by default in Firefox 55. 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, chrisdavidmills
 Last updated by: fscholz,