Return promise from setTimeout

[bluzi]

I find myself write the following snippet in almost any project I start:

const wait = (interval) => new Promise(resolve => setTimeout(resolve, interval))

That way I can use await wait(500) to delay the execution of the next lines of an async function by 500 milliseconds.

Since I find myself rewriting it every time, I figured it might as well be natively supported by returning a promise from setTimeout:

const f = async () => { 
  console.log(new Date().getTime())
  await setTimeout(, 200)
  console.log(new Date().getTime())
}

[pwolaq]

How would you approach using clearInterval to cancel the timeout? (Not to mention compatibility issues as setTimeout returns a number).

[peterjwest]

It would probably work better to just add a wait function, and it could be part of a sensibly named global object rather than window/global e.g. Timer.wait(300), since this wouldn't need to support clearTimeout and wouldn't introduce any backwards compatibility issues.

[bluzi]

How would you approach using clearInterval to cancel the timeout? (Not to mention compatibility issues as setTimeout returns a number).

Good point, though I'm not sure it's even needed in those cases. It's possible to add another callback to retrieve the timer (i.e. let timerId; await setTimeout(, 200, id => timerId = id)), but honestly I think it could be really helpful even if you cannot cancel it.

[littledan]

This repository is intended more for standard library infrastructure, as explained in https://github.com/tc39/proposal-javascript-standard-library#scope . If you want to chat about new features, Issue #16 is intended for that.

Note that setTimeout is a web platform feature, defined in the HTML specification, not a TC39 feature. You'd be better taking up your feature request there.

[zenflow]

For anyone looking into this.. here is the relevant issue for the HTML spec whatwg/html#617