Folktale: combine Result and Task (or just promise)

Question

It's a bite of broken code:

async function foo() {
  return maybeMonad
    .map((resultMonad) => resultMonad
      .matchWith({
        Error: (errorMonad) => errorMonad,
        Ok: (okMonad) => okMonad
          .map(async (context) => {
            let res = await apiRequest(context.token);
            context.data = res.data;
  
            return context;
          }),
      }));
}


await foo() // => Maybe(Promise)

The idea is to get some value from context, make a request and return context with supplemented data. But it returns a Promise in pending status. What I'm doing wrong?

Promises are in pending status until they resolve, so what's your problem? Also how are you getting Maybe(Promise) out of an async function? They implicitly wrap their return value in a Promise. — Jared Smith, Dec 18 '20 at 12:56
apiRequest resolves OK, but foo returns maybe with unresolved promise instead maybe with result — HAGer, Dec 18 '20 at 13:02
I think we're going to need a little more info about what you're actually trying to accomplish here...I'm not an *expert* in folktale/fantasyland but unless I'm completely mistaken your usage looks off. You have a lot of closure variables here that don't square with FP in general and in your specific question we probably need to see in order to help. — Jared Smith, Dec 18 '20 at 13:04
I don't think you should (can) use `async` functions to combine tasks. — Bergi, Dec 18 '20 at 13:19
Please be more specific what the code is supposed to do here. All those variable names ending in `monad` are quite meaningless - and probably wrong: types are monads, values are not. — Bergi, Dec 18 '20 at 13:20
As I have already said I need make an async api request with value from `context.token` and modify context with data getted from this request. I don't think I be able more specific. `resultMonad` and `okMonad` both are monads (Result and Result.Ok). Only `context` is plain object. — HAGer, Dec 20 '20 at 12:53
`Also how are you getting Maybe(Promise) out of an async function?` I don't think that I understood the question. — HAGer, Dec 20 '20 at 12:59

Folktale: combine Result and Task (or just promise)

0 Answers0