How to synchronously block NodeJS

Ever wanted to sleep in NodeJS?

If so, you’ve probably seen something like this:

import { promisify } from 'node:util';

const asyncSleep = promisify(setTimeout);

// sleep for 500 ms
await asyncSleep(500);

But, has that not been enough? Have you wanted to sleep synchronously, rather than asynchronously? Ever wanted to just pause the NodeJS thread for a given amount of time?

Preferably without busy waiting like while (Date.now() < someLimit) {}?

Well, want no further! I have the solution for you!

function sleep(milliseconds) {
  Atomics.wait(new Int32Array(new SharedArrayBuffer(4)), 0, 0, milliseconds);
}

// sleep for 500 ms
sleep(500);

Yes, that’s right. Now you can use sleep whevever you want in NodeJS!