Narrow inferIn vs inferOut
Maybe I misunderstood the expression, but I expected the In type to be
teamId: string | null and the Out type to be teamId: string. How can I achieve that, if not with narrow?
https://arktype.io/playground?code=import%2520%257B%2520type%2520%257D%2520from%2520%2522arktype%2522%250A%250Atype%2520In%2520%253D%2520typeof%2520Schema.inferIn%253B%250Atype%2520Out%2520%253D%2520typeof%2520Schema.inferOut%253B%250Aconst%2520Schema%2520%253D%2520type%28%257B%250A%2520%2520%2520%2520emails%253A%2520%2522string.email%255B%255D%2522%252C%250A%2520%2520%2520%2520teamId%253A%2520%255B%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522string%2520%257C%2520null%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%2522%253A%2522%252C%250A%2520%2520%2520%2520%2520%2520%2520%2520%28str%252C%2520ctx%29%253A%2520str%2520is%2520NonNullable%253Ctypeof%2520str%253E%2520%253D%253E%250A%2520%2520%2520%2520%2520%2520%2520%2520%2520%2520%2520%2520str%2520%21%253D%2520null%2520%253F%2520true%2520%253A%2520ctx.mustBe%28%2522a%2520teamId%2522%29%252C%250A%2520%2520%2520%2520%255D%252C%250A%257D%29%253B4 Replies
even if i use
type("string | null").to("string") In still infers as teamId: stringNarrow is for checking data and making assertions to determine whether its valid, but not changing that data. It can't affect the input/output of a type.
Morphs are for actually transforming data. Something like
type("string | null").pipe(data => data ?? "default") would result in the type you expect.
It seems like in the example you wrote up you are already essentially enforcing that the data must not be null, so the type really is just string in that case.perhaps if i explain my use case...
Im trying to declare a Schema to use with RHF... Where im fine with the input type being nullable, but i would like the output to be nonNullable.
I used to be able to do that with zod/v3 like this:
v4, i believe, that this does the trick:
nvm, ill address this at the type level as i should've done at the beggining
.pipe is an API you can use in ArkType as well that will allow you to change the output type, but if you're only performing validation like this and there's no transformation involved, the input and output types should be the same.
I believe that should be true for Zod as well (or if its not, it's likely just inaccurate in Zod)
https://arktype.io/docs/expressions#morph