Quick introduction to NodeJS

This article introduces NodeJS, one of the most popular and powerful Javascript server frameworks. Hopefully after reading/following this, you will decide to explore further into its capabilities. Happy coding!

1. What is Node.js?

Node.js is a JavaScript runtime built on Chrome’s V8 engine that allows you to run JavaScript on the server side. It is great for building scalable, event-driven applications, such as web servers, APIs, and real-time applications.

2. Install Node.js

• Visit the Node.js website and download the LTS (Long Term Support) version.
• After installation, verify by running:

node -v
npm -v

npm is Node’s package manager, which helps install libraries and dependencies.

3. Create a Simple Web Server

1. Create a new folder for your project:

mkdir node-tutorial
cd node-tutorial

2. Initialize a new Node.js project:

npm init -y

This will create a package.json file that stores project settings and dependencies.

3. Create a simple web server:

• Create a file called server.js:

// server.js
const http = require('http');

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello World\n');
});

const PORT = 3000;
server.listen(PORT, () => {
  console.log(`Server running at http://localhost:${PORT}/`);
});

4. Run the server:

node server.js

Visit http://localhost:3000 in your browser to see the “Hello World” message.

4. Using NPM Packages

• Let’s use a package called express, a popular web framework for Node.js.

1. Install express:

npm install express   

2. Update server.js:

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

app.get('/', (req, res) => {
 res.send('Hello from Express!');
});

const PORT = 3000;
app.listen(PORT, () => {
 console.log(`Server running at http://localhost:${PORT}/`);
});    

3. Run the server again:

node server.js

You should now see “Hello from Express!” at http://localhost:3000.

5. File Structure Best Practices

Organise your project like this for larger applications:

node-tutorial/
│
├── package.json
├── server.js
└── routes/
    └── index.js
└── controllers/
    └── userController.js

6. Nodemon for Auto-Restarting

To automatically restart the server when you change files, use nodemon:

1. Install globally:

npm install -g nodemon    

2. Run the server with nodemon:

nodemon server.js

7. Conclusion

You’ve set up a simple Node.js project with a web server and Express. From here, you can explore more advanced features like working with databases (MongoDB, MySQL), middleware, and deploying applications.