timers: allow promisified timeouts/immediates to be canceled

[jasnell]

Using the new experimental AbortController...

const { promisify } = require('util');
const sleep = promisify(setTimeout);

const ac = new AbortController();
const signal = ac.signal;

sleep(1000, undefined, { signal });

ac.abort(); // cancels the setTimeout and rejects the Promise

const { promisify } = require('util');
const immediate = promisify(setImmediate);

const ac = new AbortController();
const signal = ac.signal;

immediate(undefined, { signal });

ac.abort(); // cancels the setImmediate and rejects the Promise

This will necessarily be experimental for as long as AbortController is experimental.

Signed-off-by: James M Snell [email protected]

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[mcollina]

I like this. However I think it's time we design a few new apis for setImmediate and setTimeout that are both promisified from the start and abortable.

I do promisify(setTimeout) too many times already.

On a technical side this would have the benefit of avoiding to call promisify to change the AbortController

[jasnell]

I've been considered exporting the promisified versions of setTimeout and setImmediate as a separate namespace off timers such that we could do...

const {
  setTimeout,
  setImmediate
} = require('timers/promises');

I'm also considering a promisified version of setInterval that returns an async iterator such that...

const {
  setInterval,
} = require('timers/promises');

(async () => {
  for await (const n of setInterval(1000)) {
    console.log('tick...')
  }
})()

We also need to consider how to ref/unref promisified timers/intervals/immediates.

[jasnell]

@mcollina ... I will introduce require('timers/promises') in a separate PR

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31896/

[addaleax]

Nice :)

[mcollina]

lgtm

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31922/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/31925/

[jasnell]

Landed in bfbdc84

[codebytere]

Marking dont-land since #33527 is semver-major