父子组件通信，子组件进行watch同步修改

 
<div :parenData ="datas"></div>
 
<script>
data(){
  return{
   datas:"1"
 }
},
methods:{
  changeData(){
    this.datas= "2";
 }
},
mounted(){
  let that = this;
  settimeout(()=>{
    that.changeData();
  });
}
</script>
 
子组件
 
<div>{{msg}}</div>
 
<script>
data(){
  return{
    msg:""
  }
},
watch:{
    parendData(n,o){ //n为新值,o为旧值;
      this.msg = n;
    }
},
props:["parendData"],
mounted(){
  this.msg = this.parendData;
}
 
 
</script>

监听对象

  watch: {
    productTop: {
     handler(newData,oldData){
      this.getBarChart();
     },
     deep:true
    },
  },

  mounted: function () {
    this.getBarChart();
  },
  props:{
    productTop:Object
  },