需要用到共同屬性的時候用 extends
- call super() 是為了 call 上一層的 constructor
- 而且需要將 name 傳上去
class Dog {
constructor(name) {
this.name = name
}
sayHello() {
console.log(this.name)
}
}
class BlackDog extends Dog {
constructor(name) {
super(name)
this.sayHello()
}
test() {
console.log('test', this.name)
}
}
const d = new BlackDog('hello')
// hello
