Markdium-JavaScript - The prototype chain in depth

Markdium-JSX.jsx

class PaidPlayer extends Player {
  constructor(userName, score, balance) {
    // "this" is uninitialized yet...
    // super refers to Player in this case
    super(userName, score);
    // under the hood super is implemented with Reflect.construct
    // this = Reflect.construct(Player, [userName, score], PaidPlayer);
    this.balance = balance;
  }

  setUserName(newName) {
    this.userName = newName;
  }
}