npm & Package Management

🌿 Node.js Lesson 7 Beginner

npm (Node Package Manager) is the world's largest software registry. It manages project dependencies, scripts, and versioning through the package.json configuration file.

1 Essential npm Commands

Terminal — npm Commands

# Initialize a new project (creates package.json)
npm init -y

# Install a production dependency
npm install express

# Install a dev dependency (only needed during development)
npm install --save-dev nodemon jest

# Install packages globally
npm install -g typescript

# Update all packages to latest compatible versions
npm update

# Remove a package
npm uninstall lodash

# List installed packages (top level)
npm list --depth=0

# Audit for security vulnerabilities
npm audit
npm audit fix

# Run a script defined in package.json
npm run dev
npm test

2 package.json Deep Dive

JSON — package.json

{
  "name": "my-node-api",
  "version": "1.0.0",
  "description": "A RESTful API built with Node.js",
  "main": "src/index.js",
  "scripts": {
    "start":   "node src/index.js",
    "dev":     "nodemon src/index.js",
    "test":    "jest --coverage",
    "lint":    "eslint src/"
  },
  "dependencies": {
    "express":  "^4.18.2",
    "mongoose": "^8.1.0",
    "dotenv":   "^16.4.1"
  },
  "devDependencies": {
    "nodemon":  "^3.0.2",
    "jest":     "^29.7.0",
    "eslint":   "^8.56.0"
  },
  "engines": {
    "node": ">=18.0.0"
  }
}

3 Code Challenge

Challenge: Initialize a new Node.js project, install lodash as a dependency, and write a script that uses _.groupBy() to group an array of user objects by their role property.