这是一个实验中的功能
此功能某些浏览器尚在开发中,请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订,所以在未来版本的浏览器中该功能的语法和行为可能随之改变。
Atomics
.and()
静态方法会将给定的值与数组上的值进行按位与操作,并将结果赋值给数组,然后返回数组该位置上的旧值。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.and(typedArray, index, value)
参数
typedArray
- 一个共享的整型 typed array。例如
Int8Array
,Uint8Array
,Int16Array
,Uint16Array
,Int32Array
,或 Uint32Array
。
index
按位与操作的 typedArray 的值在数组
上的索引。
value
- 给定的按位与操作的值。
返回值
给定位置的旧值(typedArray[index])。
错误
描述
假如 a 和 b 都是 1,那么按位与运算( a & b)仅产生1。与操作的真值表为:
a |
b |
a & b |
0 |
0 |
0 |
0 |
1 |
0 |
1 |
0 |
0 |
1 |
1 |
1 |
比如,一个按位与如 5 & 1
的结果是 0001,其十进制就是
1。
5 0101
1 0001
----
1 0001
示例
var sab = new SharedArrayBuffer(1024);
var ta = new Uint8Array(sab);
ta[0] = 5;
Atomics.and(ta, 0, 1); // returns 0, the old value
Atomics.load(ta, 0); // 1
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 |
---|
and | 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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