BFE.dev solution for TypeScript puzzle
2. implement Required<T>

Looking at the code example, we can see that the requirment is to remove the ? on each property name.

To achieve this, we need to use the - , introduced in TypeScript 2.8.

- allows us to remove modifiers like readonly and ?.

type MutableRequired<T> = { -readonly [P in keyof T]-?: T[P] }; // Remove readonly and ?
type ReadonlyPartial<T> = { +readonly [P in keyof T]+?: T[P] }; // Add readonly and ?

So the answer to this question is simply a Mapped Type with -.

type MyRequired<T> = { 
  [P in keyof T]-?: T[P] 
}