vue之nextTick

<ul id="demo">
   <li v-for="item in list">{{item}}</div>
</ul>
  
 new Vue({
    el:'#demo',
    data:{
      list=[0,1,2,3,4,5,6,7,8,9,10]
    },
    methods:{
      push:function(){
          this.list.push(11);
          this.nextTick(function(){
             alert('数据已经更新')
          });

         this.$nextTick(function(){
             alert('v-for渲染已经完成')
         })
     }
}})

* `Vue.nextTick(callback)`，当数据发生变化，更新后执行回调。
* `Vue.$nextTick(callback)`，当dom发生变化，更新后执行的回调。