Node.js — Installation Guide

Option 1: nvm (Recommended)

Installing Node directly (a single installer) works, but locks you to whatever version you installed. Real projects frequently require different Node versions — nvm (Node Version Manager) lets you install and switch between multiple Node versions on the same machine, which is genuinely how most professional Node development is done, not just a nice-to-have.

bash

# macOS / Linux — install nvm itself
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.1/install.sh | bash
# restart your terminal, then verify:
nvm --version

# Install the current LTS (Long-Term Support) release of Node
nvm install --lts
nvm use --lts

# Or install a specific version
nvm install 20
nvm use 20

# List installed versions / switch between them
nvm list
nvm use 18

bash

# Windows — use nvm-windows (a separate, Windows-specific tool)
# Download the installer from: github.com/coreybutler/nvm-windows/releases
# Then, in a terminal:
nvm install lts
nvm use lts

(needs verification — exact current LTS version number changes on Node's own release schedule; check nodejs.org for the current LTS before treating any specific version number as current)

Option 2: Direct installer (simplest, least flexible)

bash

# Download from nodejs.org — choose the LTS version
# Run the installer (macOS .pkg, Windows .msi, or use your Linux
# distro's package manager)

# Ubuntu/Debian, via NodeSource (gets a current version, not the
# often-outdated version in default distro repos)
curl -fsSL https://deb.nodesource.com/setup_lts.x | sudo -E bash -
sudo apt install -y nodejs

This works fine for a single project on a single machine, but switching Node versions later means reinstalling — nvm is worth the small extra setup step for anyone doing ongoing Node work.

Verify the Install

bash

node -v     # e.g. v20.11.0
npm -v      # npm ships bundled with Node -- e.g. 10.2.4

If both commands print a version number, Node and npm are installed correctly.

Running JavaScript Two Ways

bash

# Way 1: run a file
echo 'console.log("Hello from a file");' > hello.js
node hello.js

# Way 2: the REPL (Read-Eval-Print Loop) -- an interactive shell
node
> const x = 2 + 2
> console.log(x)
4
> .exit

The REPL is genuinely useful for quickly testing a small snippet without creating a file — the same way you might use a browser console, but with Node's APIs (fs, process) available instead of DOM APIs.

Initializing a Project

bash

mkdir my-node-app && cd my-node-app
npm init -y
# creates package.json with sensible defaults -- drop -y to answer
# the setup questions (name, version, entry point) interactively instead

json

{
  "name": "my-node-app",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  }
}

package.json is the project's manifest — its dependencies, entry point, and scripts all live here. Every npm install updates this file automatically.

First "Hello World" HTTP Server

javascript

// index.js
const http = require("node:http");

const server = http.createServer((req, res) => {
  res.writeHead(200, { "Content-Type": "text/plain" });
  res.end("Hello, Node.js!\n");
});

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

bash

node index.js
# in another terminal, or a browser:
curl http://localhost:3000/

No npm install was needed for this — http is a built-in Node module, part of the runtime itself, not a package.

Next Steps

Node is installed and running a real HTTP server with zero external dependencies. Go to Fundamentals to learn the module system, the fs/path modules, and how process and environment variables work.