Atomics.waitAsync()

静态 Atomics.waitAsync() 方法在共享内存位置上异步等待，并返回 Promise 。

与 Atomics.wait() , waitAsync 是非阻塞的，可以在主线程上使用

注意：此操作仅适用于共享的 Int32Array 或 BigInt64Array 。

语法

Atomics.waitAsync(typedArray, index, value)
Atomics.waitAsync(typedArray, index, value, timeout)

Parameters

typedArray

A shared Int32Array or BigInt64Array .

index

The position in the typedArray to wait on.

value

The expected value to test.

timeout Optional

Time to wait in milliseconds. Infinity , if no time is provided.

Return value

An Object with the following properties:

async

A boolean indicating whether the value property is a Promise or not.

value

If async is false , it will be a string which is either "not-equal" or "timed-out" (only when the timeout parameter is 0 ). If async is true , it will be a Promise which is fulfilled with a string value, either "ok" or "timed-out" . The promise is never rejected.

Examples

Given a shared Int32Array .

const sab = new SharedArrayBuffer(1024);
const int32 = new Int32Array(sab);

A reading thread is sleeping and waiting on location 0 which is expected to be 0. The result.value will be a promise.

const result = Atomics.waitAsync(int32, 0, 0, 1000);
// { async: true, value: Promise {<pending>} }

In the reading thread or in another thread, the memory location 0 is called and the promise can be resolved with "ok" .

Atomics.notify(int32, 0);
// { async: true, value: Promise {<fulfilled>: 'ok'} }

If it isn't resolving to "ok" , the value in the shared memory location wasn't the expected(the value would be "not-equal" instead of a promise)or the timeout was reached(the promise will resolve to "time-out" ).