动态组件和 keep-alive 如何工作？

<script setup>
import { ref, shallowRef } from "vue";
import TabHome from "./TabHome.vue";
import TabProfile from "./TabProfile.vue";

const tabs = { home: TabHome, profile: TabProfile };
const current = shallowRef(TabHome); // which component to show
</script>

<template>
  <button @click="current = tabs.home">Home</button>
  <button @click="current = tabs.profile">Profile</button>

  <component :is="current" />   <!-- renders whichever component `current` holds -->
</template>