type Mediator = {
  colleagueChanged(colleague: Colleague): void;
};

abstract class Colleague {
  constructor(protected mediator: Mediator) {}

  changed(): void {
    this.mediator.colleagueChanged(this);
  }

  abstract event(): void; // Abstract event method
}

class ConcreteColleague1 extends Colleague {
  event(): void {
    this.changed();
  }
}

class ConcreteColleague2 extends Colleague {
  event(): void {
    this.changed();
  }
}

class ConcreteMediator implements Mediator {
  private colleague1: ConcreteColleague1 | undefined = undefined; // Initialize to null
  private colleague2: ConcreteColleague2 | undefined = undefined; // Initialize to null

  createColleagues(): void {
    this.colleague1 = new ConcreteColleague1(this);
    this.colleague2 = new ConcreteColleague2(this);

    this.colleague1.event();
    this.colleague2.event();
  }

  colleagueChanged(colleague: Colleague): void {
    if (colleague instanceof ConcreteColleague1) {
      console.log("colleague1 changed");
    } else if (colleague instanceof ConcreteColleague2) {
      console.log("colleague2 changed");
    }
  }
}

const example = {
  run(): void {
    const m = new ConcreteMediator();
    m.createColleagues();
  }
};

example.run();