Promise

A Promise represents the future result of an operation. It is pending, then fulfilled or rejected. Once settled, its result no longer changes.

const delay = ms => new Promise(resolve => {
  setTimeout(resolve, ms);
});

delay(200).then(() => console.log('Done'));

To be precise: the function passed to the Promise constructor runs synchronously. .then() handlers run as microtasks.

Pitfall: I don't wrap a function that already returns a Promise in new Promise. I also remember to return the result in a chain, so the next step waits for it.