remove null or undefined from properties of a type

Question

I need to declare a type such that removes the undefined from its property types.

Suppose we have:

type Type1{
  prop?: number;
}

type Type2{
  prop: number | undefined;
}

type Type3{
  prop: number;
}

I need to define a generic type called NoUndefinedField<T> such that NoUndefinedField<Type1> gives the same type as Type3 and the same type as NoUndefinedField<Type2>.

I tried this

type NoUndefinedField<T> = { [P in keyof T]: Exclude<T[P], null | undefined> };

But it only works for Type2.

Answer 1

Thanks to @artem, the solution is:

type NoUndefinedField<T> = { [P in keyof T]-?: NoUndefinedField<NonNullable<T[P]>> };

Notice the -? syntax in [P in keyof T]-? which removes optionality