Implement sleep(ms) and delay with value

Question

Accepted Answer

**Approach:** `new Promise(resolve => setTimeout(resolve, ms))`. For `delay`, combine with `then`.

```javascript
function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); }
function delay(fn, ms, ...args) { return sleep(ms).then(() => fn(...args)); }

// Demo
(async () => {
  console.log('start', Date.now());
  await sleep(50);
  console.log('after 50ms', Date.now());
  const v = await delay(x => x*2, 30, 21);
  console.log(v); // 42
})();
function sleepAbortable(ms, signal) {
  if (signal?.aborted) return Promise.reject(new DOMException('Aborted','AbortError'));
  return new Promise((resolve, reject) => {
    const id = setTimeout(resolve, ms);
    signal?.addEventListener('abort', () => { clearTimeout(id); reject(new DOMException('Aborted','AbortError')); }, { once: true });
  });
}
```
Used for polling, debouncing, animation sequencing.

Implement sleep(ms) and delay with value

Understand the problem

Attempt it yourself

Study the solution

Solution ready — 2 min read

Join the discussion

Discussion (0)

KEEP THE
STREAK ALIVE.

Understand the problem

Attempt it yourself

Study the solution

Solution ready — 2 min read

Join the discussion

Discussion (0)

KEEP THESTREAK ALIVE.

KEEP THE
STREAK ALIVE.