Discussion on: I promise I won't callback anymore

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Replies for: Promise.all is super useful when you've got a ton of promises to execute, although I intensely dislike how it returns an array of the results - it ...

I haven't used Promise.all very often. I think I agree with the returned array being weird. You can pass an array of objects:

Promise.all([{time: promiseToBeHereOnTime(true)}, {love: promiseToLove( true )}, {protect: promiseToProtect( true )}] )
.then(content => {
  console.log(content)
  console.log('Done! All fulfilled')
})
.catch(err => {
  console.log(err)
})

/*
[ { time: Promise { 'I promise I will be there!' } },
  { love: Promise { 'I love you so much!' } },
  { protect: Promise { 'I promise I will protect you!' } } ]
Done! All fulfilled
*/

I don't know, it probably would be easier to tweak the Promise.all implementation to server a specific purpose.

Finnian Anderson • Oct 2 '17

You still have the problem with an array being returned though - it's ugly. Named properties would be much nicer. The specific purpose would be to avoid this:

Promise
  .all(proms)
  .then(data => {
    let a = data[0]
    let b = data[1]
    let c = data[1]
    doSomethingWith(a)
    doSomethingWith(b)
    doSomethingWith(c)
  })
  .catch(console.log)

And replace it with this:

Promise
  .all(proms)
  .then(data => {
    doSomethingWith(data.a)
    doSomethingWith(data.b)
    doSomethingWith(data.c)
  })
  .catch(console.log)

Finnian Anderson • Nov 10 '17

Just spotted this, which gives another interesting approach. Still too much code duplication for my liking though. dev.to/mrm8488/using-es6-array-des...