add findCafePosts function

src/utilities/firebase.js

@@ -21,6 +21,7 @@ const firebaseConfig = {
 const app = initializeApp(firebaseConfig);
 const auth = getAuth(app);
 const provider = new GoogleAuthProvider();
+const database = getDatabase(app);
 
 
 export const signInWithGoogle = () => {
@@ -76,4 +77,6 @@ export const useDbUpdate = (path) => {
     );
 
     return [updateData, result];
-};
+};
+
+export {database};

src/utilities/posts.js

@@ -0,0 +1,33 @@
+import { useState, useEffect } from 'react';
+import { onValue, query, orderByChild, equalTo, ref } from 'firebase/database';
+import { database } from './firebase';
+
+export const findCafePosts = (cafeId) => {
+    const [data, setData] = useState(null);
+    const [error, setError] = useState(null);
+
+    useEffect(() => {
+        if (!cafeId) return
+
+        const postsRef = ref(database, `/posts`);
+        const postsQuery = query(postsRef, orderByChild('cafeId'), equalTo(cafeId));
+
+        const unsubscribe = onValue(
+            postsQuery,
+            (snapshot) => {
+                if (snapshot.exists()) {
+                    setData(snapshot.val());
+                } else {
+                    setData([]);
+                }
+            },
+            (error) => {
+                setError(error);
+            }
+        );
+
+        return () => unsubscribe();
+    }, [cafeId]);
+
+    return [data, error];
+};