获取您的自己的 Vue 服务器
App.vue
CompOne.vue
main.js
 
<template>
  <h1>The 'beforeUnmount' Lifecycle Hook</h1>
  <p>As we can see in the alert box, the text inside the p-tag is still accessible in the 'beforeUnmount' hook, right before the 'unmount' hook.</p>
  <button @click="this.activeComp = !this.activeComp">{{ btnText }}</button>
  <div>
    <comp-one v-if="activeComp"></comp-one>
  </div>
</template>

<script>
export default {
  data() {
    return {
      activeComp: true
    }
  },
  computed: {
    btnText() {
      if(this.activeComp) {
        return 'Remove component'
      }
      else {
        return 'Add component'
      }
    }
  }
}
</script>

<style scoped>
  div {
    border: dashed black 1px;
    border-radius: 10px;
    padding: 20px;
    margin: 10px;
    width: 400px;
    background-color: lightgreen;
  }
</style>                  
<template>
  <h2>Component</h2>
  <p ref="pEl">Strawberries!</p>
</template>
  
<script>
export default {
  beforeUnmount() {
    alert("beforeUnmount: The text inside the p-tag is: " + this.$refs.pEl.innerHTML);
  }
}
</script>                  
import { createApp } from 'vue'

import App from './App.vue'
import CompOne from './components/CompOne.vue'

const app = createApp(App)
app.component('comp-one', CompOne)
app.mount('#app')
                  
https://127.0.0.1:5173/