vue3中实现异步组件的方法实例

<template>
  <div class="A">
    <A></A>
  </div>
  <div class="B">
    <B></B>
  </div>
  <div>
    <C></C>
  </div>
</template>
 
<script setup>
import A from './components/A.vue'
import B from './components/B.vue'
import C from './components/C.vue'
 
</script>

<template>
  <div class="A">
    <A></A>
  </div>
  <div class="B">
    <B></B>
  </div>
  <div ref="target">
    <C v-if="targetIsVisible"></C>
  </div>
</template>
 
<script setup>
import A from './components/A.vue'
import B from './components/B.vue'
import { defineAsyncComponent, ref } from 'vue';
import { useIntersectionObserver } from '@vueuse/core'
 
const C = defineAsyncComponent(() =>           //异步引入组件
  import('./components/C.vue')
)
const target = ref(null)              //获取需要操作的dom元素
const targetIsVisible = ref(false)   //定义一个dom元素显示与隐藏开关
 
const { stop } = useIntersectionObserver(       //定义一个函数用于控制
  target,
  ([{ isIntersecting }]) => {                 //这里的isIntersecting表示的是dom元素是否进入视窗，值为true或flase
    console.log(isIntersecting);
    if (isIntersecting) {
      targetIsVisible.value = isIntersecting     //将isIntersecting赋值给开关，即表示进入视窗就显示该dom元素
    }
  },
)
 
</script>