Timers

setTimeout, setInterval, setImmediate, their clear* counterparts, and queueMicrotask are globals that follow the HTML timer API.

Example

// htmltimers.mjs
setTimeout(() => {
  const order = [];
  setTimeout(() => order.push("timeout"), 0);
  setImmediate(() => order.push("immediate"));
  Promise.resolve().then(() => order.push("promise"));
  queueMicrotask(() => order.push("microtask"));
  process.nextTick(() => order.push("nextTick"));
  setTimeout(() => console.log(order.join(" ")), 20);
}, 0);

let runs = 0;
const interval = setInterval(() => {
  if (++runs === 2) {
    clearInterval(interval);
    console.log("interval ran", runs, "times; hasRef:", interval.hasRef());
  }
}, 5);

elide run htmltimers.mjs prints:

interval ran 2 times; hasRef: true
nextTick promise microtask immediate timeout

Differences from browsers

• Timers return Node Timeout or Immediate objects, not numbers, with ref(), unref(), hasRef(), and refresh() (Timeout only).
• String handlers are not supported; the callback must be callable.
• setTimeout(callback) without a delay prints TimeoutNaNWarning before running the callback; pass 0.
• At a checkpoint, callbacks run in this order:
  1. process.nextTick
  2. Promise and queueMicrotask callbacks, in enqueue order
  3. setImmediate
  4. Zero-delay timers

Reference

Status: Full · Not measured