# Wait for the next event loop

Resolve after the current task, letting queued timers, I/O and rendering run.

Canonical: https://1loc.dev/misc/wait-for-the-next-event-loop/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Usage lines executed in Node.js 22 and headless Chromium; no external services
Updated: 2026-10-28

## Implementation

```javascript
function nextTask() { return new Promise(resolve => setTimeout(resolve, 0)); }
```

## Usage

```javascript
const order = [];
const done = nextTask().then(() => order.push('timer'));
Promise.resolve().then(() => order.push('microtask'));
order.push('sync');
await done;
order; // → ['sync', 'microtask', 'timer']
```

Lines marked → were executed in Node.js 22 and in headless Chromium, and each result was compared with the value shown. Lines marked e.g. are illustrative.

## Limits

- Promise callbacks (microtasks) still run before the timer, as the example shows.
- The HTML standard clamps timers nested more than five levels deep to at least 4 ms, so a chain of zero-delay timers is slower than it looks.
- In Node.js, setImmediate runs after pending I/O callbacks.

The function does not validate its arguments. Add checks where it receives untrusted input.

## Source and license

Original: https://github.com/phuocng/1loc/blob/14b481cf60dff1620ab1bb99a43b1f68068cdd9b/contents/wait-for-the-next-event-loop.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: See original repository history
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Documented as a reference with executed usage lines. Original MDX retained as inert source evidence.