Your Dev Environment: Terminal, Node & npm

Your Dev Environment: Terminal, Node & npm

Before you write a single route or query, you need the environment every full-stack module runs in: the terminal, the Node.js runtime, and the npm package manager. Master these and you can create a project, pull in libraries, and run your code — the loop you''ll repeat thousands of times.

The terminal: your control centre

Full-stack work happens at the command line. A handful of commands cover the basics:

pwd                 # where am I?
ls                  # list files
cd my-project       # change directory
mkdir api           # make a folder
node index.js       # run a JavaScript file

You''ll start servers, run scripts, and install packages here — not by clicking.

Node.js: JavaScript beyond the browser

Node.js is a runtime that runs JavaScript outside the browser — on your machine and on servers. It''s why one language can cover your whole stack: the same JavaScript you''d run in a browser also powers your backend. Run a file with node index.js, or type node for an interactive REPL.

npm: the package manager

You rarely build from scratch — you stand on libraries. npm installs and manages them, driven by one file:

• package.json — your project''s manifest: its name, its scripts, and its dependencies.
• npm install express adds a package (and records it in package.json).
• Installed code lands in node_modules/ — huge, regenerable, and never committed (it goes in .gitignore).
• npm run <name> runs a script defined in package.json (e.g. npm start).

dependencies vs devDependencies. Packages your app needs at runtime (like express) are dependencies; tools you only need while developing (test runners, linters, nodemon) are devDependencies (npm install --save-dev). Keeping them separate makes production installs lean.

The everyday workflow

mkdir my-api && cd my-api      # new folder
npm init -y                    # create package.json
npm install express            # add a dependency
node index.js                  # run it

Clone someone else''s project and the first thing you do is npm install — it reads package.json and rebuilds node_modules/ locally.

Common pitfalls

• Committing node_modules/. It''s enormous and machine-specific — .gitignore it and let npm install rebuild it.
• "Cannot find module ..." after cloning. You forgot npm install; the dependencies aren''t downloaded yet.
• Version drift. The package-lock.json pins exact versions so everyone installs the same tree — commit it.
• Global vs local installs. npm install -g installs system-wide; prefer local project installs so each project controls its own versions.

Why this is your on-ramp

Every later module — Backend Foundations, Databases, APIs, Deployment — starts with npm install and npm run. Being fluent in the terminal, Node, and npm means you spend your energy on the actual code, not fighting your tools.