2

function solveClasses() {
  class Developer {
    constructor(firstName, lastName) {
      this.firstName = firstName;
      this.lastName = lastName;
      this.baseSalary = 1000;
      this.tasks = [];
      this.experience = 0;
    }

    addTask(id, taskName, priority) {
      const taskObj = {
        id,
        taskName,
        priority,
      };

      if (priority == 'high') {
        this.tasks.unshift(taskObj);
      } else {
        this.tasks.push(taskObj);
      }

      return `Task id ${id}, with ${priority} priority, has been added.`;
    }

    doTask() {
      // if tasks is empty
      if (this.tasks.length == 0) {
        return `${this.firstName}, you have finished all your tasks. You can rest now.`;
      }

      let currentTask = this.tasks.shift();
      return currentTask.taskName;
    }

    getSalary() {
      return `${this.firstName} ${this.lastName} has a salary of: ${this.baseSalary}`;
    }

    reviewTasks() {
      let output = [];
      output.push('Tasks, that need to be completed:');

      this.tasks.forEach((task) => {
        let line = `${task.id}: ${task.taskName} - ${task.priority}`;
        output.push(line);
      });

      return output.join('\n');
    }
  }

  class Junior extends Developer {
    constructor(firstName, lastName, bonus, experience) {
      super(firstName, lastName);
      this.baseSalary += Number(bonus);
      this.experience = Number(experience);
    }

    learn(years) {
      this.experience += Number(years);
    }
  }

  class Senior extends Developer {
    constructor(firstName, lastName, bonus, experience) {
      super(firstName, lastName);
      this.baseSalary += Number(bonus);
      this.experience = Number(experience) + 5;
    }

    changeTaskPriority(taskId) {
      let currentTask = this.tasks.find((taskObj) => {
        return taskObj.id === taskId;
      });

      let currentTaskIndex = this.tasks.indexOf(currentTask);

      if (currentTask.priority === 'high') {
        currentTask.priority = 'low';
        this.tasks.splice(currentTaskIndex, 1);
        this.tasks.push(currentTask);
      } else {
        currentTask.priority = 'high';
        this.tasks.splice(currentTaskIndex, 1);
        this.tasks.unshift(currentTask);
      }

      return currentTask;
    }
  }

  return {
    Developer,
    Junior,
    Senior,
  };
}