对双向绑定的值进行数据类型转化

//html
<Select v-model="adddata.designee">
</Select>

//js
addPost(){ 
  let data = { };
  data.designee = this.adddata.designee //这里对designee进行数组转string类型处理，以“，”隔开
  this.$Modal.confirm({ 
  onOk: () => { 
    this.axios
        .request({ 
           url:"/tlm/ToolExpection/SetToolExpection"//接口SetToolExpection传了2个参数state，designee
           data,
           method:"post"
        })
    }
  })
}