先列出数据格式

 [{username: "1", content: "2", dataTime: 1534128070979},{username: "11", content: "22", dataTime: 1534128070979}]

从vuex中获取到的数据，然后循环渲染。dataTime是一个时间戳，然后处理的方法是_updateTimeString。再将这个方法用定时器处理。我发现只能接收到第一次的数据item的数据，其他的为空了。一开始以为是的前后顺序的问题，各种尝试没能结解决。现在我怀疑的方向是双括号模板中可能就渲染一次了，就会造成不再往下穿参了。也考虑在{{}}中直接返回一个变量，但是因为循环中在处理就比较麻烦了，求指点迷津

<template>
  <div class="comment-list" v-if="comments().length>0">
    <div class='comment' v-for="(item,index) in comments()" :key="index">
        <div class='comment-user'>
          <span class='comment-username'>
          {{item.username}}：
          </span>
        </div>
        <p>{{item.content}}</p>
        <span class='comment-createdtime'>
         {{_updateTimeString(item.dataTime)}}
        </span>
        <span class='comment-delete' @click="handleDeleteComment(index)">
          删除
        </span>
      </div>
  </div>
</template>

<script>

import { mapState, mapMutations, mapGetters } from "vuex";

export default {
  name: 'comment-list',
  data () {
    return {
      timer : Object,
      timeString:"123"
    }
  },
  created(){
    // this.timer = setInterval(this._updateTimeString,1000)
  },
  methods:{
    ...mapState({
      comments:state=>state.comments
    }),
    handleDeleteComment(index){
      console.log(this.comments())
      let newComment = this.comments().splice(index,1);
      localStorage.setItem("comments",JSON.stringify(this.comments()))
    },
    _updateTimeString:(item)=>{
      let duration = (+new Date() - item) / 1000;
      let timeString = duration > 60?`${Math.round(duration/60)}分钟前`:`${Math.round(duration)}秒前`;
      return timeString;
   }    
  },
  computed:{
   //  _updateTimeString:(item)=>{
   //  let thisItem = item;
   //  let duration = (+new Date() - item) / 1000;
   //  let timeString = duration > 60?`${Math.round(duration/60)}分钟前`:`${Math.round(duration)}秒前`;
   //  console.log(thisItem)
   //  return timeString;
   // }
  
  },
  mounted(){
    // this.timer = setInterval(this._updateTimeString,1000)
  }
}
</script>