Atomics.notify()

typedArray

An Int32Array or BigInt64Array that views a SharedArrayBuffer.

index

The position in the typedArray to wake up on.

count Optional

The number of sleeping agents to notify. Defaults to Infinity.

• Returns the number of woken up agents.
• Returns 0, if a non-shared ArrayBuffer object is used.

TypeError

Thrown if typedArray is not an Int32Array or BigInt64Array that views a SharedArrayBuffer.

RangeError

Thrown if index is out of bounds in the typedArray.

Given a shared Int32Array:

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

A reading thread is sleeping and waiting on location 0 because the provided value matches what is stored at the provided index. The reading thread will not move on until the writing thread has called Atomics.notify() on position 0 of the provided typedArray. Note that if, after being woken up, the value of location 0 has not been changed by the writing thread, the reading thread will not go back to sleep, but will continue on.

Atomics.wait(int32, 0, 0);
console.log(int32[0]); // 123

A writing thread stores a new value and notifies the waiting thread once it has written:

console.log(int32[0]); // 0;
Atomics.store(int32, 0, 123);
Atomics.notify(int32, 0, 1);

• Atomics
• Atomics.wait()
• Atomics.waitAsync()