People

function solution() {
  class Employee {
    constructor(name, age) {
      if (new.target === Employee) {
        throw new Error("Cannot make instance of abstract class Employee.");
      }

      [this.name, this.age, this.salary, this.tasks] = [name, age, 0, []];
    }

    work() {
      let current = this.tasks.shift();
      console.log(`${this.name} ${current}`);
      this.tasks.push(current);
    }

    getSalary() {
      return this.salary;
    }

    collectSalary = () =>
      console.log(`${this.name} received ${this.getSalary()} this month.`);
  }

  class Junior extends Employee {
    constructor(name, age) {
      super(name, age);
      this.tasks = ["is working on a simple task."];
    }
  }

  class Senior extends Employee {
    constructor(name, age) {
      super(name, age);
      this.tasks = [
        "is working on a complicated task.",
        "is taking time off work.",
        "is supervising junior workers.",
      ];
    }
  }

  class Manager extends Employee {
    constructor(name, age) {
      super(name, age);
      this.dividend = 0;
      this.tasks = ["scheduled a meeting.", "is preparing a quarterly report."];
    }

    getSalary() {
      return super.getSalary() + this.dividend;
    }
  }

  return { Employee, Junior, Senior, Manager };
}