Split app.js in to smaller chunks

public/js/utils.js

@@ -0,0 +1,16 @@
+export const idb = {
+    openDB(name, version, { upgrade }) {
+        return new Promise((resolve, reject) => {
+            const request = indexedDB.open(name, version);
+            request.onupgradeneeded = (event) => {
+                upgrade(request.result, event.oldVersion, event.newVersion, request.transaction);
+            };
+            request.onsuccess = () => {
+                resolve(request.result);
+            };
+            request.onerror = () => {
+                reject(request.error);
+            };
+        });
+    }
+};