Function which accepts a runtype and omits some fields

[okomarov]

Minimal example

Here's a named book

const NamedBook = Record({
  name: String,
  title: String
});

I want to create a type with the id in place of the name, so I can manually do this:

const Book = NamedBook.omit('name').extend({ id: String })

Q: Since I have 15+ runtypes, how can I write a generic function for that? I tried:

function extendWithId<T extends { name: typeof String }>(r: Record<T, false>) {
  return r.omit('name').extend({ id: String });
}

const Book = extendWithId(NamedBook);

but I get:

Argument of type '["name"]' is not assignable to parameter of type '"name"[] extends (keyof T)[] ? (keyof T)[] & "name"[] : never[]'.ts(2345)

[yuhr]

Thanks for reporting, it seems like a limitation of TS's type inference but I'll try to seek for some solution.