Your First “Hello World” in Node.js

Node.js allows us to create web servers using its built-in HTTP module. Let’s see how to set this up step by step.

Step 1: Create a New File

Create a new file called app.js (or any name you prefer) in your project folder.

Step 2: Write the Code

Here’s how to write your first “Hello World” program in Node.js:

Using CommonJS (Default Syntax)

// Import the HTTP module
const http = require('http');

// Create an HTTP server
const server = http.createServer((req, res) => {
  // Set the response header
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  // Send the response body
  res.end('Hello World\n');
});

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

Using ES Modules (Modern Syntax)

If you prefer ES Modules, supported in the latest Node.js versions, the code looks like this:

// Import the HTTP module
import http from 'http';

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

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

Step 3: Run the Program

1. Open a terminal in your project directory.
2. Run the script using the Node.js command:

node app.js

Open your browser to visit:

http://localhost:3000/

You should see the message “Hello World” displayed.