data() { return { //定義的兩個變量 city: '', country: '' } }, computed: { //寫成計算屬性 address() { const { city, country } = this; return { city, country } } }, watch: { address(nval, oval){ // 其中 nval 和 oval 對象的形式==>{city:'',country:''} console.log('變化',nval,oval) } }