class Car {
  constructor(color) {
    this.color = color;
    this.speed = 0;
  }
  //方法
  run(speed) {
    //會更新實例的speed屬性值
    this.speed = speed;
    console.log('car run'+ this.speed);
  },
};

//創建實體car
// 參數傳入給constructor
 const car1 = new Car('red');

//取得color屬性資料
const color = car1.color;   // color 等於 red

//給color賦值
car1.color = blue;

//呼叫方法
car1.run(50);  // car run 50


class ElectricCar extends Car {
  constructor(color) {
    super(color)
  }
};
//當呼叫子類別時，會去執行super(參數)，並去執行父類別的constructor，同時把參數傳給父類別的constructor
const ElectricCar1 = new ElectricCar('yellow');