UPDATE

src/App.vue

 <script setup>
 import parent from './page/ziChuanFuVal/parent.vue';
 import watchEffect from './page/watchEffect/watchEffect.vue';
+import erzi from './page/fuChuanZiVal/erzi.vue';
 </script>
 
 <template>
   <!-- <parent></parent> -->
-  <watchEffect></watchEffect>
+  <!-- <watchEffect></watchEffect> -->
+  <erzi></erzi>
 </template>
 
 <style scoped>

src/page/fuChuanZiVal/baba.vue

+<script setup>
+import {ref} from 'vue';
+import erzi from './erzi.vue';
+
+const babaMsg = ref("我来自父组件");
+</script>
+
+<template>
+    <erzi :chuanBaba="babaMsg"></erzi>
+</template>
+
+<style scoped>
+
+</style>
\ No newline at end of file

src/page/fuChuanZiVal/erzi.vue

+<script setup>
+import {ref, toRefs, defineProps } from "vue";
+const getVal = defineProps({
+    chuanBaba: String,
+});
+
+const sss = toRefs(getVal);
+</script>
+    
+<template>
+    <div>
+        获取来自父组件的值：{{ sss }}
+    </div>
+</template>
+
+<style scoped>
+
+</style>
\ No newline at end of file