**Course Title:** Modern JavaScript Programming: From Fundamentals to Full-Stack Development **Section Title:** Back-End Development with Node.js and Express **Topic:** Build a RESTful API using Node.js, Express, and a database of your choice.(Lab topic) **Objective:** In this lab, you will build a RESTful API using Node.js, Express, and a database of your choice. You will learn how to design and implement API endpoints, handle requests and responses, and interact with a database. **Prerequisites:** * Knowledge of Node.js, Express, and database concepts * Familiarity with JavaScript fundamentals, including data types, functions, and object-oriented programming * Understanding of RESTful API principles and HTTP methods (GET, POST, PUT, DELETE) **Choosing a Database:** For this lab, you can choose any database management system (DBMS) you are comfortable with. Popular choices include: * MongoDB (NoSQL, document-based database) * PostgreSQL (Relational database management system) * MySQL (Relational database management system) Each database has its strengths and weaknesses. MongoDB is a popular choice for Node.js applications due to its flexible schema and scalability. PostgreSQL and MySQL are well-established relational databases suitable for complex data relationships. **Setting up the Project:** Create a new Node.js project using `npm init` and install the required dependencies: ```bash npm install express mongoose body-parser ``` Replace `mongoose` with a database driver of your choice (e.g., `pg` for PostgreSQL or `mysql2` for MySQL). **Designing the API:** Define the API endpoints and their corresponding HTTP methods: * `GET /users`: Retrieve all users * `GET /users/:id`: Retrieve a user by ID * `POST /users`: Create a new user * `PUT /users/:id`: Update a user * `DELETE /users/:id`: Delete a user **Implementing API Endpoints:** Create a new file `api.js` and import the required dependencies: ```javascript const express = require('express'); const router = express.Router(); const User = require('./models/User'); // Import the User model // Retrieve all users router.get('/users', async (req, res) => { try { const users = await User.find(); res.json(users); } catch (err) { res.status(500).json({ message: 'Error fetching users' }); } }); // Retrieve a user by ID router.get('/users/:id', async (req, res) => { try { const user = await User.findById(req.params.id); if (!user) { res.status(404).json({ message: 'User not found' }); } else { res.json(user); } } catch (err) { res.status(500).json({ message: 'Error fetching user' }); } }); // Create a new user router.post('/users', async (req, res) => { try { const user = new User(req.body); await user.save(); res.json(user); } catch (err) { res.status(400).json({ message: 'Error creating user' }); } }); // Update a user router.put('/users/:id', async (req, res) => { try { const user = await User.findByIdAndUpdate(req.params.id, req.body, { new: true }); if (!user) { res.status(404).json({ message: 'User not found' }); } else { res.json(user); } } catch (err) { res.status(500).json({ message: 'Error updating user' }); } }); // Delete a user router.delete('/users/:id', async (req, res) => { try { await User.findByIdAndRemove(req.params.id); res.json({ message: 'User deleted' }); } catch (err) { res.status(500).json({ message: 'Error deleting user' }); } }); ``` **Connecting to the Database:** Create a new file `database.js` and import the database driver: ```javascript const mongoose = require('mongoose'); // Connect to MongoDB mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true }); // Define the User model const userSchema = new mongoose.Schema({ name: String, email: String }); const User = mongoose.model('User', userSchema); module.exports = User; ``` Replace the database connection string with your own. **Starting the Server:** Create a new file `server.js` and import the API router: ```javascript const express = require('express'); const app = express(); const apiRouter = require('./api'); app.use(express.json()); app.use('/api', apiRouter); app.listen(3000, () => { console.log('Server started on port 3000'); }); ``` **Testing the API:** Use a tool like `curl` or a REST client (e.g., Postman) to test the API endpoints: ```bash curl http://localhost:3000/api/users curl http://localhost:3000/api/users/123 curl -X POST -H "Content-Type: application/json" -d '{"name":"John Doe","email":"john.doe@example.com"}' http://localhost:3000/api/users curl -X PUT -H "Content-Type: application/json" -d '{"name":"Jane Doe"}' http://localhost:3000/api/users/123 curl -X DELETE http://localhost:3000/api/users/123 ``` **Conclusion:** In this lab, you built a RESTful API using Node.js, Express, and a database of your choice. You designed and implemented API endpoints, handled requests and responses, and interacted with a database. **What's Next?** In the next topic, we will discuss the importance of testing in modern JavaScript applications. You will learn how to write unit tests, integration tests, and end-to-end tests for your JavaScript code. **Leave a Comment or Ask for Help:** If you have any questions or need help with this lab, please leave a comment below. We will be happy to assist you. **External Resources:** * Express.js Documentation: <https://expressjs.com/en/api.html> * Mongoose Documentation: <https://mongoosejs.com/docs/api.html> * MongoDB Documentation: <https://docs.mongodb.com/manual/> * PostgreSQL Documentation: <https://www.postgresql.org/docs/>