const robot = {
  _model: '1E78V2',
  _energyLevel: 100,
  get energyLevel(){
    if(typeof this._energyLevel === 'number') {
      return 'My current energy level is ' + this._energyLevel
    } else {
      return "System malfunction: cannot retrieve energy level"
    }
  }
};

console.log(robot.energyLevel);


const person = {
  _firstName: 'John',
  _lastName: 'Doe',
  get fullName() {
    if (this._firstName && this._lastName){
      return `${this._firstName} ${this._lastName}`;
    } else {
      return 'Missing a first name or a last name.';
    }
  }
}
 
// To call the getter method: 
person.fullName; // 'John Doe'