Refactor code structure for improved readability and maintainability

lib/mongoose.ts

@@ -1,11 +1,5 @@
 import mongoose from "mongoose"
 
-const MONGODB_URI = process.env.MONGODB_URI
-
-if (!MONGODB_URI) {
-    throw new Error("Please define the MONGODB_URI environment variable inside .env.local")
-}
-
 let cached = (global as any).mongoose
 
 if (!cached) {
@@ -13,6 +7,11 @@ if (!cached) {
 }
 
 async function connectToMongoDB() {
+    const mongodbUri = process.env.MONGODB_URI
+    if (!mongodbUri) {
+        throw new Error("Please define the MONGODB_URI environment variable")
+    }
+
     if (cached.conn) {
         return cached.conn
     }
@@ -22,7 +21,7 @@ async function connectToMongoDB() {
             bufferCommands: false,
         }
 
-        cached.promise = mongoose.connect(MONGODB_URI!, opts).then((mongoose) => {
+        cached.promise = mongoose.connect(mongodbUri, opts).then((mongoose) => {
             return mongoose
         })
     }