Coding3 - 📘 Connecting to MongoDB

🧠 What You’ll Learn

In this lesson, you’ll:

• Set up MongoDB for your project
• Create a reusable connection file using Mongoose
• Load the connection string from the .env file

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✅ Step 1: Install Mongoose

In your terminal, run:

npm install mongoose
npm install --save-dev @types/mongoose

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✅ Step 2: Add Your MongoDB URI to .env

Update your .env file:

SERVER_PORT=5000
MONGODB_URI=mongodb://localhost:27017/my-api

💡 Replace my-api with your preferred database name.

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✅ Step 3: Create MongoDB Connection File

File: src/dbconnect.ts

import mongoose from "mongoose";

const connectDB = async (mongoURI: string) => {
    try {
        await mongoose.connect(mongoURI);
        console.log('✅ MongoDB Connected: ', mongoURI);
    } catch (error) {
        console.error('❌ MongoDB connection failed:', error);
        process.exit(1); // exit app if connection fails
    }
}

export default connectDB;

✅ This file handles the connection to your MongoDB database and shows a helpful log message.

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✅ Step 4: Use connectDB() in app.ts

Update your src/app.ts to use the connection:

import 'dotenv/config';
import express from 'express';
import connectDB from './dbconnect';

const app = express();
const PORT = process.env.SERVER_PORT || 5000;

// 🧠 Connect to MongoDB
connectDB(process.env.MONGODB_URI || '');

// Middleware
app.use(express.json());

// Test Route
app.get('/health', (_req, res) => {
  res.json({ message: 'Ok' });
});

// Start Server
app.listen(PORT, () => {
  console.log(`🚀 Server running at http://localhost:${PORT}`);
});

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🧪 Step 5: Run and Verify

Run your project:

npm start

✅ You should see something like:

✅ MongoDB Connected:  mongodb://localhost:27017/my-api
🚀 Server running at http://localhost:5000

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📦 Folder Structure So Far

REST-API/
├── src/
│   ├── app.ts
│   └── dbconnect.ts
├── .env
├── nodemon.json
├── package.json
├── tsconfig.json

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✅ What’s Next?

In Lesson 4, you’ll create your User model and build a user authentication system using signup, login, and logout routes.