Where communities thrive


  • Join over 1.5M+ people
  • Join over 100K+ communities
  • Free without limits
  • Create your own community
People
Repo info
Activity
  • 18:56
    typescript-bot synchronize #34503
  • 18:36
    mjbvz edited #34651
  • 18:36
    mjbvz unassigned #34651
  • 18:36
    mjbvz edited #34651
  • 18:35
    pirix-gh opened #34651
  • 18:31
    andrewbranch demilestoned #33121
  • 18:31
    andrewbranch milestoned #33121
  • 18:29
    andrewbranch closed #30858
  • 18:29
    andrewbranch labeled #30858
  • 18:29
    sandersn synchronize #15575
  • 18:29
    sandersn synchronize #28460
  • 18:29
    sandersn synchronize #31641
  • 18:28

    sandersn on fix-element-access-decl-kind

    (compare)

  • 18:28

    sandersn on master

    Treat any mix of element/prop a… (compare)

  • 18:28
    sandersn closed #34649
  • 18:28
    sandersn closed #34642
  • 18:26
    Knagis opened #34650
  • 18:24
    andrewbranch labeled #30858
  • 18:24
    andrewbranch unlabeled #30858
  • 18:19
    sandersn labeled #34640
Keith Layne
@keithlayne
I must have seen an augmentation instead of the actual definition, my bad
Gareth Jones
@G-Rath
ok want to see something interesting?
interface Mx {
  v: string;
}

const promiseTuple = async <T1, T2>(t1: T1, t2: Promise<T2>): Promise<[T1, T2]> =>
  [t1, await t2];

const doThings = async (): Promise<Array<[string, Mx[]]>> => Promise.all([
  promiseTuple('hello', Promise.resolve([{ v: 'sunshine' }])),
  promiseTuple('world', await [{ v: 'peace' }])
]);

doThings().then(r => r.forEach(console.log));
pretty sure that's a bug :grimacing:
AnyhowStep
@AnyhowStep
I'm pretty sure it's not
Gareth Jones
@G-Rath
whys that?
they have the same output
AnyhowStep
@AnyhowStep
(await x) does not give you an expression of type Promise<typeof x>, I'm sure
It's just syntactic sugar
Gareth Jones
@G-Rath
Yeah, that's what I'm questioning
why doesn't it give you an expression of that type? b/c as you say, it's syntactic sugar, so it does give that expression in Node (iirc)
AnyhowStep
@AnyhowStep
If it did return a promise, this would work,
function returnPromise () : Promise<number> {
  return (await 1);
}
Gareth Jones
@G-Rath
which it does
once you add the missing async keyword
AnyhowStep
@AnyhowStep
image.png
Exactly. The async part is the problem here
Gareth Jones
@G-Rath
oh ffs
no wait what
async is in my code
for a second I thought it was I'd just missed async, but nope: async is there
so your example doesn't really relate to mine, as far as I can tell
AnyhowStep
@AnyhowStep

function takesNumberOnly (x : number) {
  console.log(x+1);
}
async function returnPromise ()  {
  const x = await 1;
  takesNumberOnly(x);
  takesNumberOnly(await 1);
}
If (await 1) is an expression of type Promise<number>
Then the second call to takesNumberOnly would not work
Gareth Jones
@G-Rath
Yeah I see. and you're right; this is turning how I figured it would
it's contextual, but too complex to type like that
AnyhowStep
@AnyhowStep
It's sytactic sugar for,
function returnPromise2 ()  {
  Promise.resolve(1)
    .then((x) => {
      takesNumberOnly(x);
      Promise.resolve(1)
        .then((y) => {
          takesNumberOnly(y);
        });
    });
}
Gareth Jones
@G-Rath
yeah yeah
AnyhowStep
@AnyhowStep
gdi gitter highlighting
Gareth Jones
@G-Rath
you need to add ts
im actually slightly disppointed in myself for not putting that together XD
but cheers for the sanity check
AnyhowStep
@AnyhowStep
Sometimes, adding ts doesn't make it any better =x
No problem <3
Gareth Jones
@G-Rath
yeah I know
but so yeah: it's b/c of the await in the inner fn
also ugh ffs my whole fn is redundant XD which is annoying b/c I thought that originally :joy:
AnyhowStep
@AnyhowStep
I didn't even notice till you said it =x
I need to up my code review skillz
Bruce Pascoe
@fatcerberus
(await 1) is expression of type number
It auto-wraps 1 in a promise and then unwraps it
You basically just waited an extra tick for a value you already had :P
AnyhowStep
@AnyhowStep
Kick him down some more :soccer:
Derya Aydede
@Derya
is async/await actually just syntactic sugar?
i was under the impression that it actually is not the exact same as the non-async equivalent

Without await, promises in for loops would be a hassle, especially if each iteration depends on the previous iteration (so no Promise.all())
I think you have to actually use a recursive function for the loop if you can't use await.

Memory is rusty and I'm too lazy to try it out

Derya Aydede
@Derya
yeah you'd have to make some nightmarish construct
thank you based async/await
Bruce Pascoe
@fatcerberus
It’s syntactic sugar as far as the behavior goes, but it being syntax makes it a lot easier to write certain constructs, like AnyhowStep says