Building a RESTful API with Express.js

When building a MERN stack application, the backend API is responsible for handling data interactions and serving the requested data to the frontend. In this section, we will focus on building a RESTful API using Express.js, a popular framework for Node.js.

Express.js is a minimal and flexible web application framework that provides a robust set of features for web and mobile applications. It simplifies the process of creating APIs by providing a clear and concise syntax.

To get started with building a RESTful API using Express.js, make sure you have Node.js and npm (Node Package Manager) installed on your system. Follow these steps:

1. Create a new directory for your API project.

2. Open a terminal or command prompt and navigate to the project directory.

3. Run the following command to create a new package.json file:

1npm init

4. Answer the prompts to configure your project. You can keep the default values for most of the prompts.

5. Install Express.js as a dependency by running the following command:

1npm install express

6. Create a new JavaScript file, for example, app.js, and open it in your preferred code editor.

7. Import the Express.js module and create an instance of the Express application:

1const express = require('express');
2const app = express();

8. Define routes for your API endpoints. For example, you can define a route to handle GET requests to the /api/users endpoint:

1app.get('/api/users', (req, res) => {
2  // Logic to retrieve users data from the database
3  // Send the users data as a response
4  res.json({
5    users: [
6      { id: 1, name: 'John Doe' },
7      { id: 2, name: 'Jane Smith' }
8    ]
9  });
10});

9. Start the Express application by listening on a specific port. For example:

1const port = 3000;
2app.listen(port, () => {
3  console.log(`Server is running on port ${port}`);
4});

By following these steps, you will have a basic RESTful API set up using Express.js. You can define additional routes and add more complex logic as needed to handle different HTTP methods and interact with your database.

Remember to install any additional dependencies you may need for your API, such as a database driver or an authentication library. Express.js has a rich ecosystem of middleware and extensions that can help you add functionality to your API.