Generic Types and Inheritance in TypeScript

generic-inheritance.ts

interface User {
  name: string;
}

interface HappyUser extends User {
  clap: () => void;
}

function printName<T extends User>(someone: T): T {
  console.log(someone.name);
  return someone;
}

const benny: HappyUser = {
  name: 'Benny',
  clap: (): void => {
    console.log('👏');
  }
};

const person = printName(benny);
person.clap();