Setting Up Your First Node.js Application Step-by-Step
Installing Node.js
Node.js must first be installed before running JavaScript outside the browser.
Installing Node.js also installs:
Node runtime
npm package manager
After installation, JavaScript files can be executed directly from the terminal.
Checking Installation Using Terminal
After installation, verify Node.js using:
node -v
This displays the installed Node.js version.
Check npm version:
npm -v
Understanding Node REPL
REPL stands for:
Read
Evaluate
Print
Loop
It is an interactive Node.js environment where JavaScript code can be tested directly.
Start REPL using:
node
Example:
> 2 + 2
4
Exit REPL using:
.exit
Creating First JS File
Create a JavaScript file:
index.js
Add code:
console.log("hello world");
Running Script Using node Command
Run JavaScript files using:
node index.js
Output:
hello world
Node.js executes the file using the V8 engine.
Writing Hello World Server
Node.js can also create servers.
Example:
const http = require("http");
const server = http.createServer((req, res) => {
res.end("Hello World");
});
server.listen(3000, () => {
console.log("server running");
});
Now visiting:
http://localhost:3000
shows:
Hello World
Initializing a Project
Most Node.js projects start using:
npm init -y
or:
pnpm init
This creates:
package.json
which stores project configuration and dependencies.
Initializing TypeScript
For TypeScript projects:
tsc --init
This creates:
tsconfig.json
which contains TypeScript configuration.
Installing Express
Express is one of the most popular Node.js frameworks.
Install using:
npm install express
or:
pnpm add express
Basic Express Server Snippet
const express = require("express");
const app = express();
app.get("/", (req, res) => {
res.send("Hello from Express");
});
app.listen(3000, () => {
console.log("server running");
});
This creates a simple Express server running on port 3000.
Common Daily Starter Setup
A common backend setup flow:
mkdir project-name
cd project-name
npm init -y
npm install express
tsc --init