npm

npm is the default package manager. Install deps, run scripts, use npx to run binaries.

4 min read Level 1/5 #nodejs#npm#npx

What you'll learn

Install runtime + dev dependencies
Run scripts and binaries
Know the alternatives (pnpm, yarn, bun)

npm ships with Node. It’s how you pull in the vast library ecosystem (~3M packages and counting).

Installing Deps

npm install express              # runtime dep
npm install --save-dev vitest    # dev-only dep
npm install                       # install everything in package.json

This:

Creates node_modules/ if missing
Updates package.json (adds to deps)
Updates package-lock.json (locks exact versions)

npm install and npm i are the same. So are --save-dev and -D.

Removing

npm uninstall express

Updating

npm outdated      # show what's behind
npm update        # update within the semver range in package.json

To bump major versions, edit package.json manually or use npm-check-updates.

Running Scripts

npm run dev        # runs scripts.dev from package.json
npm test           # alias — works for "test" and "start"

`npx` — Run a Package Without Installing

npx create-vite my-app    # downloads & runs once
npx tsx script.ts          # if tsx isn't installed globally

npx is part of npm. It checks node_modules/.bin, then downloads.

`node_modules/`

The flat folder where deps live. Never commit it — add to .gitignore. With the lock file, anyone can npm install and get the same tree.

Alternatives

Tool	Pitch
npm	Default. Ships with Node.
pnpm	Faster, disk-efficient (hard links). Strict about deps.
yarn	Older alternative. Yarn 4 (Berry) does PnP.
bun	All-in-one (runtime + pkg mgr). Fast installs.

All read the same package.json and produce a node_modules/. Lock files differ:

package-lock.json (npm)
pnpm-lock.yaml (pnpm)
yarn.lock (yarn)
bun.lockb (bun)

Pick one per project — don’t mix.

End of Chapter

That wraps the basics. Next chapter: Node’s standard library — the parts of Node that aren’t on window.

The File System →