🔧 refactor: Move MongoDB connection logic to a separate module and make database name optional

api/lib/db/connect.js

@@ -0,0 +1,53 @@
+require('dotenv').config();
+const mongoose = require('mongoose');
+const MONGO_URI = process.env.MONGO_URI;
+const MONGO_DB_NAME = process.env.MONGO_DB_NAME;
+
+if (!MONGO_URI) {
+  throw new Error('Please define the MONGO_URI environment variable');
+}
+
+/**
+ * Global is used here to maintain a cached connection across hot reloads
+ * in development. This prevents connections growing exponentially
+ * during API Route usage.
+ */
+let cached = global.mongoose;
+
+if (!cached) {
+  cached = global.mongoose = { conn: null, promise: null };
+}
+
+async function connectDb() {
+  if (cached.conn && cached.conn?._readyState === 1) {
+    return cached.conn;
+  }
+
+  const disconnected = cached.conn && cached.conn?._readyState !== 1;
+  if (!cached.promise || disconnected) {
+    const opts = {
+      bufferCommands: false,
+      // useNewUrlParser: true,
+      // useUnifiedTopology: true,
+      // bufferMaxEntries: 0,
+      // useFindAndModify: true,
+      // useCreateIndex: true
+    };
+
+    if (MONGO_DB_NAME) {
+      opts.dbName = MONGO_DB_NAME;
+    }
+
+    mongoose.set('strictQuery', true);
+    cached.promise = mongoose.connect(MONGO_URI, opts).then((mongoose) => {
+      return mongoose;
+    });
+  }
+  cached.conn = await cached.promise;
+
+  return cached.conn;
+}
+
+module.exports = {
+  connectDb,
+};

api/lib/db/connectDb.js

@@ -1,7 +1,6 @@
 require('dotenv').config();
 const mongoose = require('mongoose');
 const MONGO_URI = process.env.MONGO_URI;
-const MONGO_DB_NAME = process.env.MONGO_DB_NAME;
 
 if (!MONGO_URI) {
   throw new Error('Please define the MONGO_URI environment variable');
@@ -34,10 +33,6 @@ async function connectDb() {
       // useCreateIndex: true
     };
 
-    if (MONGO_DB_NAME) {
-      opts.dbName = MONGO_DB_NAME;
-    }
-
     mongoose.set('strictQuery', true);
     cached.promise = mongoose.connect(MONGO_URI, opts).then((mongoose) => {
       return mongoose;