UPDATE

src/page/fuChuanZiVal/baba.vue

 <script setup>
-import baVal = ref(0);
 import erzi from './erzi.vue';
 
-const fuValJia = () => {
-    baVal++;
-}
+let baVal = "我是来自父组件的值";
 </script>
-
 <template>
-    <button @click="fuValJia">父组件的值加一</button>
     <erzi :title="baVal"></erzi>
 </template>
-
 <style scoped>
 
 </style>
\ No newline at end of file

src/page/fuChuanZiVal/erzi.vue

 <script setup>
 const props = defineProps({
-    title: {
-        type:String,
-        default: "默认值"
-    }
+    title: String,
 });
 
-console.log(props.title);
 </script>
     
 <template>