Sleep / delay with a Promise
Pause an async function for a number of milliseconds, with optional cancellation through AbortSignal.
- JavaScript
- GreenSnippets
- MIT
- Executed with Node.js 22
function sleep(ms, signal) {
return new Promise((resolve, reject) => {
if (signal?.aborted) return reject(signal.reason);
const timer = setTimeout(() => {
signal?.removeEventListener("abort", onAbort);
resolve();
}, ms);
function onAbort() {
clearTimeout(timer);
reject(signal.reason);
}
signal?.addEventListener("abort", onAbort, { once: true });
});
}Example / expected output
await sleep(500); // resumes after about half a secondHow it works
A promise-based timer makes retry loops and demos readable. Passing an AbortSignal lets the caller cancel the wait, and the timer is cleared so nothing keeps the process alive.
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