statelyai
Bug: higher-order guards types do not allow dynamic params
Description
When using guard params (https://stately.ai/docs/guards#guard-object), they need to be called as an object. But higher order guards like not do not support them at the Type Level.
Expected result
guard: and([
not({
type: "isGuessValid",
params: ({ event }) => ({ index: event.index }),
}),
not("isLetterUsed"),
]),
To not throw any TS error
Actual result
Type 'GuardPredicate<{ chars: { content: string; guessIndex?: number | undefined; }[]; guess: { content: string; valid?: boolean | undefined; }[]; solution: string[]; }, { type: "addLetter"; index: number; }, unknown, { type: "isLetterUsed"; params: undefined; } & ParameterizedObject>' is not assignable to type 'Guard<{ chars: { content: string; guessIndex?: number | undefined; }[]; guess: { content: string; valid?: boolean | undefined; }[]; solution: string[]; }, { type: "addLetter"; index: number; }, undefined, { ...; } | ... 1 more ... | { ...; }> | undefined'.
Reproduction
https://tsplay.dev/Wo13LN
Additional context
See https://discord.com/channels/795785288994652170/1181599123112210512
This one is quite hard to fix - as mentioned on Discord. So far I failed to figure out anything but I'll continue trying.
So I got some news. I managed to provide the contextual parameter type in a situation like this in a standalone repro of the problem: TS playground. This widens (at least in this scenario) type: 'checkFoo' and it becomes type: string - which in turn breaks type-checking. It can be fixed~ by slapping some as const on it but it would be best if we could avoid this.
Oh, and I can bring back this string literal narrowing by introducing TType extends string, like here: TS playground. I'm not yet sure how this technique will scale with and and or though.