geohash and message query stuff

src/lib/Firebase/messages.js

@@ -0,0 +1,16 @@
+import { collection, query, where, getDocs } from 'firebase/firestore'; // tools for building and running db queries
+import { db } from './config'; // database connection
+import { getQueryPrefix } from '$lib/utils/geohash'; // convert coordinates into geohash string 
+
+export async function getNearbyMessages(lat, lng) {
+    const prefix = getQueryPrefix(lat, lng);
+
+    const q = query(
+        collection(db, 'messages'),
+        where('geohash', '>=', prefix),
+        where('geohash', '<', prefix + 'z')
+    );
+
+    const snapshot = await getDocs(q);
+    return snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
+}