[eurasiantiger]

Many devs unnecessarily nest Promises like that.

    async function getData() {
      return new Promise((resolve) => {
        const res = fetch(…);
        resolve(res);
      });
    }

The response above is wrapped in THREE different Promises! One from fetch, one manually created, and one implicitly created by `async`.

The code above behaves exactly the same as

    function getData() {
       return fetch(…);
    }

or even just

    fetch(…);

[RobertWHurst]

I've been on teams working on node projects for like 15 years. I've never seen someone who understands promises or async await do that. You'd have to know nothing about what the async keyword actually does to be compelled to do that.

[hn_throwaway_99]

I mean, I know its a bit of linguistic flourish, but considering NodeJS was only initially released 12 years ago, that's quite a feat!

[eurasiantiger]

I have seen plenty of (usually junior front-end) devs resort to exactly this kind of cargo cult coding and magical thinking.

[wiml]

Well, they're junior devs. You're supposed to help them get past that stage, not just throw away all your tools.

[eurasiantiger]

What made you think I haven’t been helping them?

[joe_guy]

I'm going out on a limb here and assuming the issues with their code don't begin and end with async.

[cercatrova]

> I've never seen someone who understands promises or async await do that. You'd have to know nothing about what the async keyword actually does to be compelled to do that.

> usually junior front-end

So you agree with each other then?

[eurasiantiger]

Good day, axe handle.

[Cpoll]

> function getData() { return fetch(…); }

I feel like there are advantages to making it `async function`, even if it's superfluous, because it signals to readers and to static code analysis that the function returns a promise. That's assuming the return type of fetch(...) can't be inferred by static analysis and developer tooling.

[Kwantuum]

> the type of fetch() can't be inferred by static analysis

That is preposterous.

[Cpoll]

It's not. One might assume it's Node fetch, but parent post was just using a specific example to make a general point. Fetch can be `any`thing.

Would you say the same thing about

function getData() { return mysteryFunction(…); }

[garyrob]

I'm a newbie with respect to JS and especially promises and async/await, but I need to learn. If you could point me to some resource that does a really good job of explaining all this, I'd appreciate it very much. I expect that I wouldn't be the only one. What's something you'd recommend to a junior developer so that they wouldn't be one of the "many devs", as you put it, who do the wrong thing?

[magnio]

Not the parent, but I recommend understanding the event loop first: here [0] is a very good talk. Then, read the chapter on promise on javascript.info [1], as it explains the problems Promise set out to solve (callback hell), then as usual the excellent MDN article [2].

[0] https://www.youtube.com/watch?v=8aGhZQkoFbQ

[1] https://javascript.info/async

[2] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guid...

[garyrob]

Just watched that video. Thanks! Excellent resource. Moving on to your other links.

[stareatgoats]

The whole async/await paradigm (including promises) is trying to fit square pegs into round holes (trying to make async processes look like they are synchronous). Just look at the comments on this page; even though async/await/promises have been around for years they are still causing difficulties for even the most experienced devs.

It doesn't mean it can't be mastered, it can, but the whole paradigm is so fraught with pitfalls and conceptual difficulties that an codebase that uses it in any extensive way will forever be unstable. The whole thing is supposed to help against callback hell, but that can be better solved by a simple thenable object.

Not a popular opinion I know, but there you go.

[eurasiantiger]

> trying to make async processes look like they are synchronous

That is NOT what async/await is about — after all, async explicitly marks functions as asynchronous. Not exactly trying to hide that.

Async/await is syntactic sugar. It is there to make working with Promises less verbose.

That is almost all: await pauses current function execution in the main event loop, which is an important detail

[doliveira]

> simple thenable object

Wouldn't you simply be reinventing promises?

[stareatgoats]

Actually no. A promise is a thenable oject, true, but a complex one. Simple thenable objects are in the simplest form objects that internally just holds an array of methods defined in each then() block. These methods then execute one after another at runtime. Any slightly experienced dev can probably create a library object or class like this in under 100 loc as a dropin replacement for most promises needs, and get a firm grasp of the internals in addition.

The usage of such an object won't be as terse and seemingly elegant as await syntax, but this is part of the problem: with await/promises so much of the complex logic is hidden from view and instead needs to reside the head of each dev, where it needs to compete with a thousand other things that need attention. It's an expression of the constant but unhealthy tendency towards golfing that pervades our field IMO.

[doliveira]

Yeah, up until you need some extra functionality and you fall into the Inner-Platform effect (https://en.m.wikipedia.org/wiki/Inner-platform_effect). Promises are a well-established and battle-tested standard, I'd be very weary of someone reimplementing them for no reason.

[lmc]

This doesn't directly answer your question, but... something to watch out for is experienced developers can also struggle with promises and async code if they've spent most of their career working with sync code. And when we 'get' it, the difficulty of the journey is often understated. This stuff can be hard, so don't sweat it if it seems frustrating. (On the other hand, it may be easier if you don't have years of sync patterns to mentally set aside )

[garyrob]

Thanks for this feedback.

[eurasiantiger]

Nobody has yet noticed that it’s only wrapped in TWO Promises. I take it nobody really understands the syntax, author included.