Atomics.sub()

Atomics.sub() 静态方法在数组中的给定位置减去给定值，并返回该位置的旧值。这个原子操作保证在修改后的值被写回之前不会发生其他写操作。

语法

Atomics.sub(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: 要被 value 值减去的 typedArray 索引位置。
value: 要减去的数字。

返回值

给定位置的旧值 (typedArray[index])。

异常

假如 typedArray 不是允许的整型之一，则抛出 TypeError。
假如 typedArray 不是一个共享的整型 typed array，则抛出 TypeError。
如果 index 超出了 typedArray 的边界，则抛出 RangeError。

例子

const sab = new SharedArrayBuffer(1024);
const ta = new Uint8Array(sab);
ta[0] = 48;

Atomics.sub(ta, 0, 12); // returns 48, the old value
Atomics.load(ta, 0); // 36

规范

Specification	Status	Comment
ECMAScript Latest Draft (ECMA-262) Atomics.sub	Draft	Initial definition in ES2017.

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	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`sub`	Chrome 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 No support 16 — 17 Notes No support 16 — 17 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 No	Opera No support No	Safari 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.	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 No	Safari iOS No support No	Samsung Internet Android No support No Notes No support No 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.	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.

语法

参数

返回值

异常

例子

规范

浏览器支持

Legend

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