Js面向对象

class Animal {
  constructor(su,num){
    this.su = su;
    this.num = num
  }
  add(){
    return this.su+''+this.num
  }
  addt(){
    return this.su+'-------'+this.num
  }
}
class Ssa extends Animal {
  constructor(su,num){
    super(su,num)
  }
}
let a = new Animal('ss','sadsad')
console.log(a)//Animal {su: 'ss', num: 'sadsad'}
console.log(a.add())//sssadsad
let b = new Ssa('sadasd','-asdasd')
console.log(b)//Ssa {su: 'sadasd', num: '-asdasd'}
console.log(b.addt())//sadasd--------asdasd