1-1 $nextTick
1-1 $nextTick底层源码是使用定时器+Promise实现的1-2 $nextTick里面的代码会在DOM更新后执行1-3 $nextTick会在所有的子组件加载完毕之后再执行
<div id="app"><div ref="test">test</div></div><script>new Vue({el:"#app",created() {console.log(this.$refs)this.$nextTick(()=>{console.log(this.$refs)})},mounted() {console.log(this.$refs)},})</script>
