npm Package Manager

Comprehensive npm (Node Package Manager) commands and workflows for JavaScript and Node.js development.

Installation & Setup

Install Node.js and npm

# Using Node Version Manager (recommended)
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.0/install.sh | bash
nvm install node
nvm use node

# Direct download from nodejs.org
# Or using package managers:
# macOS: brew install node
# Ubuntu: sudo apt install nodejs npm
# Windows: choco install nodejs

Basic Package Operations

Command	Description
npm install package_name	Install package locally
npm install -g package_name	Install package globally
npm uninstall package_name	Uninstall package
npm update	Update all packages
npm update package_name	Update specific package
npm list	List installed packages
npm list -g	List global packages

Project Management

Project Initialization

Command	Description
npm init	Initialize new project
npm init -y	Initialize with defaults
npm init @scope	Initialize with scoped template
npm create package_name	Create project with template

Dependency Management

Command	Description
npm install	Install all dependencies
npm install --save package	Install and save to dependencies
npm install --save-dev package	Install and save to devDependencies
npm install --save-optional package	Install as optional dependency
npm install --no-save package	Install without saving

Package Information

Command	Description
npm search keyword	Search for packages
npm info package_name	Show package information
npm view package_name	View package details
npm outdated	Show outdated packages
npm audit	Check for vulnerabilities
npm audit fix	Fix vulnerabilities

Scripts and Execution

Script Management

Command	Description
npm run script_name	Run custom script
npm start	Run start script
npm test	Run test script
npm run build	Run build script
npm run dev	Run development script

Example package.json Scripts

{
  "scripts": {
    "start": "node server.js",
    "dev": "nodemon server.js",
    "build": "webpack --mode production",
    "test": "jest",
    "lint": "eslint src/",
    "format": "prettier --write src/"
  }
}

Version Management

Semantic Versioning

Command	Description
npm version patch	Increment patch version
npm version minor	Increment minor version
npm version major	Increment major version
npm version prerelease	Create prerelease version

Package Installation by Version

Command	Description
npm install package@1.2.3	Install specific version
npm install package@latest	Install latest version
npm install package@next	Install next/beta version
npm install package@^1.2.0	Install compatible version

Configuration

npm Configuration

Command	Description
npm config list	Show configuration
npm config get key	Get configuration value
npm config set key value	Set configuration value
npm config delete key	Delete configuration

Common Configuration

Setting	Description
npm config set registry https://registry.npmjs.org/	Set registry
npm config set init-author-name "Your Name"	Set default author
npm config set init-license "MIT"	Set default license
npm config set save-exact true	Save exact versions

.npmrc File

# Project .npmrc
registry=https://registry.npmjs.org/
save-exact=true
engine-strict=true
fund=false
audit-level=moderate

# Global .npmrc (~/.npmrc)
init-author-name=Your Name
init-author-email=your.email@example.com
init-license=MIT

Publishing

Package Publishing

Command	Description
npm login	Login to npm registry
npm whoami	Check logged in user
npm publish	Publish package
npm publish --access public	Publish scoped package publicly
npm unpublish package@version	Unpublish specific version

Publishing Workflow

# 1. Update version
npm version patch

# 2. Build package
npm run build

# 3. Test package
npm test

# 4. Publish
npm publish

# 5. Tag release
git tag v1.0.0
git push origin v1.0.0

Advanced Usage

Workspaces (npm 7+)

{
  "name": "my-monorepo",
  "workspaces": [
    "packages/*",
    "apps/*"
  ]
}

Command	Description
npm install --workspaces	Install all workspace dependencies
npm run test --workspaces	Run tests in all workspaces
npm run build --workspace=package-a	Run command in specific workspace

Package Linking

Command	Description
npm link	Create global link
npm link package_name	Link to global package
npm unlink package_name	Unlink package

Cache Management

Command	Description
npm cache verify	Verify cache integrity
npm cache clean --force	Clear cache
npm cache ls	List cached packages

Security

Security Auditing

Command	Description
npm audit	Check for vulnerabilities
npm audit --audit-level high	Check high severity only
npm audit fix	Fix vulnerabilities automatically
npm audit fix --force	Force fix (may break changes)

Package Verification

Command	Description
npm pack	Create tarball
npm pack --dry-run	Show what would be packed
npm install package.tgz	Install from tarball

Performance Optimization

Faster Installation

# Use npm ci for CI/CD
npm ci

# Parallel installation
npm install --prefer-offline

# Skip optional dependencies
npm install --no-optional

# Production only
npm install --production

Alternative Package Managers

Manager	Installation	Benefits
Yarn	npm install -g yarn	Faster, deterministic
pnpm	npm install -g pnpm	Disk space efficient
Bun	curl -fsSL https://bun.sh/install | bash	Extremely fast

Troubleshooting

Common Issues

Problem	Solution
Permission errors	Use nvm or fix permissions
Package conflicts	Delete node_modules and reinstall
Outdated npm	npm install -g npm@latest
Registry issues	npm config set registry https://registry.npmjs.org/

Debugging

Command	Description
npm doctor	Check npm environment
npm ls	Check dependency tree
npm ls --depth=0	Show top-level dependencies
npm why package_name	Show why package is installed

Reset and Clean Install

# Clean install
rm -rf node_modules package-lock.json
npm install

# Clear npm cache
npm cache clean --force

# Reset npm configuration
npm config edit

Best Practices

Package.json Management

{
  "name": "my-project",
  "version": "1.0.0",
  "description": "Project description",
  "main": "index.js",
  "engines": {
    "node": ">=16.0.0",
    "npm": ">=8.0.0"
  },
  "dependencies": {
    "express": "^4.18.0"
  },
  "devDependencies": {
    "jest": "^29.0.0",
    "eslint": "^8.0.0"
  },
  "peerDependencies": {
    "react": ">=16.0.0"
  }
}

Development Workflow

1. Version Pinning: Use exact versions for critical dependencies
2. Lock Files: Commit package-lock.json to version control
3. Security: Regular security audits with npm audit
4. Testing: Test before publishing with npm pack
5. Documentation: Maintain comprehensive README

Performance

1. CI/CD: Use npm ci in continuous integration
2. Caching: Leverage npm cache in CI environments
3. Selective Installation: Use --production for production builds
4. Alternative Managers: Consider yarn or pnpm for large projects
5. Registry: Use private registry for internal packages