Node.js

An Open Source, cross-platform JavaScript runtime environment

• event driven and asynchronous
• can be used to develop server-side applications
• also useful for webdev toolchains, transpiling, dev server, etc.

Intall options

• download installer from https://nodejs.org/en
• use package manager (e.g. HomeBrew on MacOS)
• use nvm (Node Version Manager)

npm

• Installed with Node.js
• A library / registry for JavaSript software packages
  • name comes from “Node Package Manager”, but does more now
• Command-line tools to:
  • install packages
  • manage dependencies
  • manage development environment by running scripts

Install a package from the npm library / registry

npm install <package>

• install options
  • --save-dev: package is for development only
  • -g: install package globally (i.e. in your system)

Listed installed packages

npm list # or npm list -g . to list global packages

Initialize Node project

npm init # npm create (for Vite)

Run script

npm run <script-name>

Execute package

npm exec <package>

Update a package

npm update <package> # or npm up <package>

Node project files

package.json

• list of all packages installed in project
• every npm install adds to this file, often with many dependent packages as well
• has information to re-create installed packages
  • node init: if package.json exists, installs all packages
• add to your repo

package-lock.json

• information to more precisely reproduce /node_modules
• add to your repo

node_modules/

• quickly becomes very large, 1000s of small files
• 🔥 important to ignore node_modles/ (must be in .gitignore)
• avoid synching with Dropbox, GDrive, etc.
• can just delete it, then run npm install to re-install all packages

npx

Execute an arbitrary command from an npm package (either one installed locally, or fetched remotely), in a similar context as running it via npm exec

npx some-package

• If some-package is in your path (i.e. it was installed using npm), then it runs the local version of the package
• If some-package is not in your path (i.e. not installed), then it downloads the latest version of the package and runs it