vue操作虚拟dom去掉字符串最后一个逗号(使用ref)

<template>
  <div>
    <span v-for="(item,index) in caller" :key='index' ref="groupname">{{caller.groupname}},</span>
  </div>
</template>

 export default {
  data(){
    return{
      caller:[]    
    }
  },
  update(){
    //删除小组名称最后一项的逗号
    let _this=this;
    if(_this.$refs.groupname){
      let groupname=_this.$refs.groupname;
      let lastGruop=groupname[groupname.length-1];
      let txtGroupName=groupname.innerText;
      let lastGroups=txtGroupName.split("");
      if(lastGroups[lastGroups.length-1]==","){
        lastGroups.length=lastGroups.length-1;
      }
      lastGroups=lastGroups.join("");
      lastGroup.innerText=lastGroups;
    }
  }
}