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Ben Halpern
Ben Halpern

Posted on

Visual Studio Code can now convert your long chains of Promise.then()'s into async/await automagically

VSCode is continuing to evolve in pretty fascinating ways.

I'm curious about whether I'd actually make use of something like this, but I definitely find it interesting if it gets out of the way when not being used.

Top comments (25)

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dance2die profile image
Sung M. Kim • Edited on

I'm curious about whether I'd actually make use of something like this

async/await sometimes looks less readable than promise.then counter-part.

So one can use it when async/await version makes it more readable 😎.

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razvanilin profile image
Razvan Ilin

I agree with this completely. I tried refactoring my code to async/await because it was the new thing, but I ended up sticking with promises because the code was much cleaner

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wormss profile image
WORMSS

It's very useful when you have if's especially if you have conditional diamond forks.

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ben profile image
Ben Halpern Author

Yes, agreed.

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lenaggar profile image
Mahmoud ElNaggar

I completely agree .. I can orchestrate the chains of thens in a Promise however it makes it more readable for me

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dbelyaeff profile image
Dmitriy Belyaev

Few releases later VSCode will learn how to make coffee β˜•

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nickyhajal profile image
Nicky Hajal

If I recall correctly, the changelog also mentioned this was thanks to a summer intern on the VSCode team. Pretty cool!

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ben profile image
Ben Halpern Author

Wow, that’s fantastic!

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jsgoose profile image
Jonathan Sexton

That's a really cool aspect of this, go summer intern!

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qm3ster profile image
Mihail Malo

Cool, and there are definitely valid use cases for this, but I am scared the people who are too enthusiastic about async/await will abuse this and the amount of PRs that change

const getPosts = () =>
  firebase
    .firestore()
    .collection('posts')
    .orderBy('timestamp')
    .get()
    .then(querySnapshot => querySnapshot.map(doc => doc.data()))

export default {
  name: 'Home',
  data: () => ({
    posts: []
  }),
  async asyncData() {
    return { posts: await getPosts() }
  }
}

into

export default {
  name: "Home",
  data: () => ({
    posts: []
  }),
  async asyncData() {
    let posts = []
    await firebase
      .firestore()
      .collection("posts")
      .orderBy("timestamp")
      .get()
      .then(querySnapshot => {
        querySnapshot.forEach(doc => {
          posts.push(doc.data())
        })
      })
    return { posts: posts }
  }
}
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julieneric profile image
Julien Eric

Why would it leave a then hanging off of an async call?

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qm3ster profile image
Mihail Malo • Edited on

Which one are you talking about?

You mean the abuser would write the following?

export default {
  name: "Home",
  data: () => ({
    posts: []
  }),
  async asyncData() {
    let posts = []
    const querySnapshot = await firebase
      .firestore()
      .collection("posts")
      .orderBy("timestamp")
      .get()
    querySnapshot.forEach(doc => {
      posts.push(doc.data())
    })
    return { posts: posts }
  }
}
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ben profile image
Ben Halpern Author

Credit: @umaar , of course.

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umaar profile image
Umar Hansa

Hey Ben, I'd be down for an AMA as @nickytonline suggested (thanks Nick for the kind words about the course 😊️)

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ben profile image
Ben Halpern Author

Sounds good to me πŸ˜„

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nickytonline profile image
Nick Taylor

You should ask @umaar if he'd be up for an AMA. He's a dev tools guru. I signed up for his moderndevtools.com last year and it'sπŸ”₯πŸ’―

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ahmadawais profile image
Ahmad Awais ⚑️

VSCode is awesome! πŸ‘Œ

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gene profile image
Gene

// Unrelated
I've read a lot of good things about axios, but never from a DEV community member yet. I wish to read one soon! Especially why fetch is better than axios instead of why axios is better than fetch like what most articles I've read says so.

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shawnlan profile image
shawnlan

We have to be careful and understand how async/await works. The converted code doesn't behave exactly the same in the twitter example. Before conversion the function returns a promise that resolves with undefined, and console.log(err) is called. After conversion, the function returns a promise that rejects, and console.log(err) is not called. We would assume the converted code should behave the same; thus it's a bug IMO.

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asparallel profile image
AsParallel

Definitely useful for legacy code updating. Also nice given as far as I'm aware there's no autofixer for it in linters.

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ben profile image
Ben Halpern Author

I was thinking more about writing new code than updating old code. That’s a very strong use case!

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jboku8 profile image
JBoKu8

Wow amazing

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voodooattack profile image
Abdullah Ali

Beautiful.

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bgadrian profile image
Adrian B.G.

Watchout I saw some bugs reported on this feature, like all refactorings keep an eye on it and add more tests πŸ˜€

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