BFE.dev solution for TypeScript puzzle
5. implement Pick<T, K>

Looking at the description, MyPick<T, K> should generate an object type which has property names listed in K, so we should use Mapped Type.

type MyPick<T, K> = {
  [P in K]: T[P]
}

This doesn't work since TypeScript complaints about T[P] unless P is the property key of T, we can add the type constraint on K.

type MyPick<T, K extends keyof T> = {
  [P in K]: T[P]
}