Note that SharedArrayBuffer
was disabled by default in all major browsers on 5 January, 2018 in response to Spectre. Chrome re-enabled it in v67 on platforms where its site-isolation feature is enabled to protect against Spectre-style vulnerabilities.
The SharedArrayBuffer()
constructor is used to create a SharedArrayBuffer
object representing a generic, fixed-length raw binary data buffer, similar to the ArrayBuffer
object.
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
Syntax
new SharedArrayBuffer([length])
Parameters
length
- The size, in bytes, of the array buffer to create.
Return value
A new SharedArrayBuffer
object of the specified size. Its contents are initialized to 0.
Examples
Always use the new operator to create a SharedArrayBuffer
SharedArrayBuffer
constructors are required to be constructed with a new
operator. Calling a SharedArrayBuffer
constructor as a function without new
will throw a TypeError
.
var sab = SharedArrayBuffer(1024);
// TypeError: calling a builtin SharedArrayBuffer constructor
// without new is forbidden
var sab = new SharedArrayBuffer(1024);
Specifications
Browser compatibility
| Desktop | Mobile | Server |
---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | Android webview | Chrome for Android | Firefox for Android | Opera for Android | Safari on iOS | Samsung Internet | Node.js |
---|
SharedArrayBuffer() constructor | Chrome
Full support
68-
Full support
68
-
No support
60 — 63
- Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This was a temporary removal while mitigations were put in place.
| Edge
Full support
79-
Full support
79
-
No support
16 — 17
- Notes Support was removed to mitigate speculative execution side-channel attacks (Windows blog).
| Firefox
Full support
79-
Full support
79
-
Full support
57
- Notes Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
- Disabled 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. -
No support
55 — 57
-
No support
46 — 55
- Disabled 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.
| IE
No support
No | Opera
No support
No | Safari
No support
10.1 — 11 | WebView Android
No support
60 — 63-
No support
60 — 63
- Notes 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.
| Chrome Android
No support
60 — 63-
No support
60 — 63
- Notes 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.
| Firefox Android
Full support
57-
Full support
57
- Notes Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
- Disabled 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. -
No support
55 — 57
-
No support
46 — 55
- Disabled 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.
| Opera Android
No support
No | Safari iOS
No support
10.3 — 11 | Samsung Internet Android
No support
No-
No support
No
- Notes 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.
| nodejs
Full support
8.10.0 |
---|
Legend
-
Full support
- Full support
-
No support
- No support
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.
See also