twop / ts-union Goto Github PK

Great library! It'd be even more useful if it supported Haskell's Either type.

• I'm submitting a ...
  [ ] bug report
  [ ] feature request
  [ ] question about the decisions made in the repository
  [x] question about how to use this project

If I have some arbitrary union like:

const MyUnion = Union({
  Str: of<string>(),
  Num: of<number>()
})
type MyUnion = typeof MyUnion.T

And I have a function that maybe throws a MyUnion:

try {
  foobar();
}
catch (err: unknown) {
  // ?? how to tell if `err` is a `MyUnion` here?
}

How can I tell if the returned value is a MyUnion? There doesn't seem to be any function in the API like MyUnion.is(maybeAUnion) that could narrow the type.

• I'm submitting a ...
  [x] question about the decisions made in the repository
  [x] question about how to use this project

• Summary
  Why should I use this library over the other one?

• I'm submitting a ...
  [ ] bug report
  [ x ] feature request
  [ ] question about the decisions made in the repository
  [ ] question about how to use this project

• Summary
  Something unionize has and can be of use if you need to deal with well established contract like FSA. Currently, I'd need to manually extend the result object influencing performance and - potentially, but hopefully not - breaking some existent behaviours.

• I'm submitting a ...
  [ ] bug report
  [x] feature request
  [ ] question about the decisions made in the repository
  [ ] question about how to use this project

• Summary

I'm wondering if it's possible to support recursive ADTs, for example a classic linked list. My own attempts at a generalised ADT library have failed in this regard since the TS compiler can't handle the recursive type aliases

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  [ ] bug report
  [ ] feature request
  [ ] question about the decisions made in the repository
  [x] question about how to use this project

• Summary

How do I create an equivalent of this Rust type, including an interface for all of it's members?

enum LoadingEnum<T> {
  Loading,
  Loaded(T)
}

const LoadingEnum = Union(T => ({
  Loading: of(null),
  Loaded: of(T)
}));
type LoadingEnum<T> = ???

• I'm submitting a ...
  [ ] bug report
  [ ] feature request
  [ ] question about the decisions made in the repository
  [✅] question about how to use this project

• Summary
  Is there a way to compare two UnionVal<Record> for equality?

My scenario is: nested routes, so I want to construct some matcher functions (exact, leftside a -> b, ...) with a signature like <Record, T = UnionVal<Record>>(a: T, b: T) => boolean.

So far I have managed to get it done by comparing .k and then .p, but the docs say that the runtime API is not stable.