npm (Node Package Manager) is the default package manager for Node.js. It hosts over 2 million packages and manages project dependencies through package.json.
Every Node project starts with npm init which creates the package.json manifest file.
# Initialize a new project (interactive):
npm init
# Initialize with defaults (skips questions):
npm init -y
# Install a package and save to dependencies:
npm install express
# Install a dev-only package:
npm install --save-dev nodemon
# Install a specific version:
npm install lodash@4.17.21
# Install all dependencies from package.json:
npm install
# Uninstall a package:
npm uninstall express
# List installed packages:
npm list --depth=0
# package.json structure:
# {
# "name": "my-app",
# "version": "1.0.0",
# "main": "index.js",
# "scripts": {
# "start": "node index.js",
# "dev": "nodemon index.js",
# "test": "jest"
# },
# "dependencies": { "express": "^4.18.2" },
# "devDependencies": { "nodemon": "^3.0.1" }
# }