The byteLength accessor property represents the length of an SharedArrayBuffer in bytes.
sab.byteLength
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. |
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 601 | No2 |
55 — 57 46 — 555 |
No | No | 10.1 —? |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | 601 | 601 | ? |
55 — 57 46 — 555 |
No | No | ? |
1. Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.
2. Support was removed to mitigate speculative execution side-channel attacks (Windows blog).
3. Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
4. From version 57: this feature is behind the javascript.options.shared_memory preference (needs to be set to true). To change preferences in Firefox, visit about:config.
5. From version 46 until version 55 (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.
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer/byteLength