Getting Started with Node.js

Back to Node.js
Arjit Sharma
01 Min

Creating Your First Node.js Project

Step 1: Initialize a Node Project

mkdir node-app
cd node-app
npm init -y # This creates a package.json file, which stores project metadata and dependencies.

Note - When you install packages, they are stored in the node_modules folder.

Step 2: Create Entry File

// index.js
console.log("Hello, Node.js!");

Run with:

node index.js

Note - Each file in Node.js is treated as a module with its own scope (not global like in browsers).

How Node Executes your Code

  1. Node.js starts its runtime (V8 engine + libuv).
  2. Loads your JavaScript file.
  3. Parses and compiles it.
  4. Executes it inside the event loop.
  5. Exits when no more work remains.

If you create a server or set timers, the event loop stays active, keeping your program running.

Creating a Basic HTTP Server

Node has a built-in http module to create web servers:

const http = require("http"); // loads Node’s built-in HTTP module

const server = http.createServer((req, res) => { // (req, res) represents the incoming request and outgoing response
  res.writeHead(200, { "Content-Type": "text/plain" }); // sets the status code and headers
  res.end("Welcome to Node.js!"); // sends the response
});

// starts listening for connections
server.listen(3000, () => {
  console.log("Server running at http://localhost:3000");
});
  • require() is used to import modules in Node.js (CommonJS module system).
  • The callback passed to createServer runs every time a request is received.
  • Port 3000 is where the server listens.
  • The server keeps running because it keeps the event loop active.

Built-in Modules

Node.js comes with useful built-in modules:

  • fs → File system operations
  • path → File path utilities
  • os → System info
  • http → Web servers
const fs = require("fs");
fs.writeFileSync("hello.txt", "Hello World!");

We will learn more about these built-in modules in next article.

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