function Device(name) {
  this.name = name;
  this.isOn = false;
}

Device.prototype.turnOn = function() {
  this.isOn = true;
  return `${this.name} is now on`;
};

function Smartphone(name, model) {
  Device.call(this, name);
  this.model = model;
}

Smartphone.prototype = Object.create(Device.prototype);
Smartphone.prototype.constructor = Smartphone;

Smartphone.prototype.turnOn = function() {
  const result = Device.prototype.turnOn.call(this);
  return `${result} (model: ${this.model})`;
};

const myPhone = new Smartphone('iPhone', '13 Pro');
console.log(myPhone.turnOn());