首先要明确:
Vue 实现响应式并不是数据发生变化之后 DOM 立即变化,而是按一定的策略进行 DOM 的更新。
$nextTick 是在下次 DOM 更新循环结束之后执行延迟回调,在修改数据之后使用 $nextTick,则可以在回调中获取更新后的 DOM
实例
<div class="app">
<div ref="msgDiv">{{msg}}</div>
<div v-if="msg1">Message got outside $nextTick: {{msg1}}</div>
<div v-if="msg2">Message got inside $nextTick: {{msg2}}</div>
<div v-if="msg3">Message got outside $nextTick: {{msg3}}</div>
<button @click="changeMsg">
Change the Message
</button>
</div>
new Vue({
el: '.app',
data: {
msg: 'Hello Vue.',
msg1: '',
msg2: '',
msg3: ''
},
methods: {
changeMsg() {
this.msg = "Hello world."
this.msg1 = this.$refs.msgDiv.innerhtml
this.$nextTick(() => {
this.msg2 = this.$refs.msgDiv.innerHTML
})
this.msg3 = this.$refs.msgDiv.innerHTML
}
}
})
//结果
Message got outside $nextTick:Hello Vue.
Message got inside $nextTick:Hello world.
Message got outside $nextTick: Hello Vue.
参考