vue watch同时监听两个值的变化并执行方法

先用computed定义一个address对象，然后再去watch addres

data() {
  return {
    city: '',
    country: ''
  }
},
computed: {
  address() {
    const { city, country } = this
    return {
      city,
      country
    }
  }
},
watch: {
  address(val){
     console.log(val)
　}
20 }