Update app.js with optimized code structure

backend/app.js

@@ -1,53 +1,54 @@
-import dotenv from "dotenv";
+import dotenv from 'dotenv';
+import express from 'express';
+import cookieParser from 'cookie-parser';
+import cors from 'cors';
 
-import express from "express";
-import cookieParser from "cookie-parser";
-import { errorHandler } from "./src/utilis/ApiError.js";
-import cors from "cors";
+import { errorHandler } from './src/utilis/ApiError.js'; // Custom error handler
 
-const app = express();
+// Import all routes
+import userRouter from './src/routes/user.routes.js';
+import contactUsRouter from './src/routes/contactus.routes.js';
+import appointmentRouter from './src/routes/appointment.routes.js';
+import medicineRouter from './src/routes/medicine.routes.js';
+import CartRouter from './src/routes/UserCart.routes.js';
+import PaymentRouter from './src/routes/payment.routes.js';
+import TestimonialRouter from './src/routes/testimonial.routes.js';
 
-// dotenv configuration
-dotenv.config({
-  path: "./.env",
-});
+// Load environment variables
+dotenv.config({ path: './.env' });
+
+const app = express();
 
-// cors middleware configuration connects frontend to backend
+// Middleware configurations
+// Setup CORS to allow requests from trusted origins, including credentials support
 app.use(
   cors({
     origin: [process.env.FRONTEND_URL, process.env.DASHBOARD_URL],
-    method: ["GET", "POST", "DELETE", "PUT"],
+    methods: ['GET', 'POST', 'DELETE', 'PUT'],
     credentials: true,
-  }),
+  })
 );
+
+// Middleware for parsing cookies and request bodies
 app.use(cookieParser());
-app.use(express.json());
-app.use(express.urlencoded({ extended: true }));
-
-// import routes
-import userRouter from "./src/routes/user.routes.js";
-import contactUsRouter from "./src/routes/contactus.routes.js";
-import appointmentRouter from "./src/routes/appointment.routes.js";
-import medicineRouter from "./src/routes/medicine.routes.js";
-import CartRouter from "./src/routes/UserCart.routes.js";
-import PaymentRouter from "./src/routes/payment.routes.js";
-import TestimonialRouter from "./src/routes/testimonial.routes.js";
-
-// Define the root route
-// app.get('/', (req, res) => {
-//   res.send('Welcome to the homepage!');
-// });
-
-// routes declaration
-app.use("/api/v1/user", userRouter);
-app.use("/api/v1/message", contactUsRouter);
-app.use("/api/v1/appointment", appointmentRouter);
-app.use("/api/v1/medicines", medicineRouter);
-app.use("/api/v1/medicines-cart", CartRouter)
-app.use("/api/v1/payment", PaymentRouter)
-app.use("/api/v1/testimonial", TestimonialRouter)
-
-
-// error middleware
+app.use(express.json()); // Automatically parse JSON payloads
+app.use(express.urlencoded({ extended: true })); // Parse URL-encoded data
+
+// API route handlers
+app.use('/api/v1/user', userRouter);
+app.use('/api/v1/message', contactUsRouter);
+app.use('/api/v1/appointment', appointmentRouter);
+app.use('/api/v1/medicines', medicineRouter);
+app.use('/api/v1/medicines-cart', CartRouter);
+app.use('/api/v1/payment', PaymentRouter);
+app.use('/api/v1/testimonial', TestimonialRouter);
+
+// Default route (optional for base-level check)
+app.get('/', (req, res) => {
+  res.send('API is running successfully.');
+});
+
+// Error handling middleware for unified API error responses
 app.use(errorHandler);
+
 export default app;