/* Write the type MyRequired — makes all optional fields mandatory */ type User = { id?: number name?: string } type MyRequired<T> = { } const user1: MyRequired<User> = { id: 1, name: "John" } const user2: MyRequired<User> = { id: 1 }

The MyRequired<T> type can be implemented using mapped types in TypeScript by removing the ? modifier from all properties of T. This is done using the -? operator before the property key:

// Remove optionality from all properties

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

// Example usage

type User = {
  id?: number
  name?: string
}

const user1: MyRequired<User> = { id: 1, name: "John" } // correct
const user2: MyRequired<User> = { id: 1 } // error, missing required field name