fix(types): fix ExtractedValue type

[ben-tilden]

Noticed this while working with extract

TypeScript does not automatically distribute conditionals unless the generic type itself represents a union. So, in ExtractedValue, V['value'] is not distributed unless inferred as a separate generic type.

EDIT: Adding issue link

// Testing distributed conditional over an indexed access type
interface Obj {
  value: string | number;
}

type TestIndexedObj<V extends { value: unknown }> = V['value'] extends number ? 'extends number' : 'does not extend number';
type TestIndexedObjResult = TestIndexedObj<Obj> // "does not extend number"

// Testing distributed conditional over a union
type ObjValue = Obj['value'];

type TestUnion<V> = V extends number ? 'extends number' : 'does not extend number';
type TestUnionResult = TestUnion<ObjValue> // "does not extend number" | "extends number"

// Testing distributed conditional over an inferred generic from an indexed access type
type TestInferredIndexedObj<V extends { value: unknown }> = V['value'] extends infer U ? (U extends number ? 'extends number' : 'does not extend number') : never;
type TestInferredIndexedObjResult = TestInferredIndexedObj<Obj> // "does not extend number" | "extends number"

[fb55]

Thanks for this awesome PR! Could you add a types test to validate this works (and keeps working), using the same expectTypeOf already used for a bunch of type checks?

[ben-tilden]

Apologies for the delay - added!

[fb55]

Very nice!