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。

语法

Atomics.and(typedArray, index, value)

参数

typedArray
一个共享的整型 typed array。例如 Int8ArrayUint8ArrayInt16ArrayUint16ArrayInt32Array,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

  • 假如 typedArray 不是允许的整型之一,则抛出 TypeError
  • 假如 typedArray 不是一个贡献的 typed array,则抛出 TypeError
  • 如果 index 超出了 typedArray 的边界,则抛出 RangeError

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

Specification Status Comment
Unknown
Atomics.and
Unknown Initial definition.

浏览器支持

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung InternetNode.js
Basic supportChrome Full support 68
Full support 68
No support 60 — 63
Notes
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 16
Notes
Full support 16
Notes
Notes Support was removed to mitigate speculative execution side-channel attacks (Windows blog).
Firefox Full support 57
Notes Disabled
Full support 57
Notes Disabled
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
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 NoOpera No support NoSafari No support 10.1 — ?WebView Android No support 60 — 63
Notes
No support 60 — 63
Notes
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
Notes
No support 60 — 63
Notes
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
Notes Disabled
Full support 57
Notes Disabled
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
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 NoSafari iOS No support NoSamsung Internet Android No support Nonodejs 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.

相关

文档标签和贡献者

此页面的贡献者: fscholz, Ende93
最后编辑者: fscholz,