下面这个是父组件中请求数据的例子，父组件的代码如下：

<template>
  <ChildDemo v-if="user" :user="user" />
  <div v-else>
    <p>loading...</p>
  </div>
</template>
<script setup lang="ts">
import { ref, onMounted } from "vue";
import ChildDemo from "./Child.vue";
const user = ref(null);
async function fetchUser() {
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve({
        name: "张三",
        phone: "13800138000",
      });
    }, 2000);
  });
}
onMounted(async () => {
  user.value = await fetchUser();
});
</script>