Atomics
.add()
静态方法会将给定的值加到数组里的某个特定位置上,并返回该位置的旧值。此原子操作保证在写上修改的值之前不会发生其他写操作。
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.
语法
Atomics.add(typedArray, index, value)
参数
typedArray
- 一个共享的整型 typed array。例如
Int8Array
,Uint8Array
,Int16Array
,Uint16Array
,Int32Array
,或者 Uint32Array
。
index
typedArray
中的位置,该位置数值会被加总并更新。
value
- 增加的数字。
返回值
给定位置的旧值(typedArray[index])
。
错误
示例
var sab = new SharedArrayBuffer(1024);
var ta = new Uint8Array(sab);
Atomics.add(ta, 0, 12); // returns 0, the old value
Atomics.load(ta, 0); // 12
规范
浏览器支持
Update compatibility data on GitHub | Desktop | Mobile | Server |
---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | Safari on iOS | Samsung Internet | Node.js |
---|
add | 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
No support
16 — 17-
No support
16 — 17
- Notes Support was removed to mitigate speculative execution side-channel attacks (Windows blog).
| Firefox
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.
| IE
No support
No | Opera
No support
No | Safari
No support
10.1 — ? | 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.
| Edge Mobile
?
| 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
No | Samsung Internet Android
No support
No | nodejs
Full support
8.10.0 |
---|
Legend
-
Full support
- Full support
-
No support
- No support
-
Compatibility unknown
- Compatibility unknown
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.
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