Vue使用.sync 实现父子组件的双向绑定数据问题

<certificate-input
    :p_model.sync='pname'>
 </certificate-input>

 <certificate-input :p_model="pname" @update:p_model="val => pname= val"></certificate-input>

<template>
 <div>
 <certificate-input
    :p_model.sync='pname'
    :xi_model.sync="xiname">
 </certificate-input>
</div>
</template>
import CertificateInput from '../common/CertificateInput.vue'
export default {
 name: 'fathor',
 components: {
  CertificateInput 
 },
 data() {
  return {
   pname:"",
   xiname:""
 }  
}

<template>
 <div>
  <x-input
   title="姓名" 
   v-model="name" 
   ></x-input>
  <x-input title="身份证号" 
    v-model="idCard" 
    placeholder="请输入身份证号"
    required>
  </x-input>
 </div>
</template>
<script type="text/javascript">
 import { XInput} from 'vux'
 export default{
  name:'certificateInput',
  props:["p_model","xi_model"],
  components:{
   XInput
  },
  data(){
   return{
    name:this.p_model,
    idCard:this.xi_model
   }
  },
  watch:{
  
   p_model(val) { 
    this.address = val;
   },
   name(val){
  //设置监听，如果改变就更新 p_model
    this.$emit('update:p_model', val)
   },
   xi_model(val){
    this.certificate = val
   },
   idCard(val){
     this.$emit('update:xi_model', val)
   }
  }
 }
</script>

 name(val){
  //设置监听，如果改变就更新 p_model
    this.$emit('update:p_model', val)
}