npm & package.json
📌 Covered in this chapter:
npm init · npm install · Dependencies vs devDependencies · Semantic Versioning · npm scripts · npx
Master npm — Node's package manager — including installing dependencies, semantic versioning, npm scripts, and npx.
1npm & package.json — What You'll Learn
Master npm — Node's package manager — including installing dependencies, semantic versioning, npm scripts, and npx.
Here's everything this chapter covers, in the order you'll learn it:
- What npm is
- Creating package.json with npm init
- Installing packages
- Uninstalling packages
- Development dependencies vs production dependencies
- Package versioning
- Semantic versioning (major.minor.patch)
- package-lock.json's role
- npm scripts for common tasks
- npx to run packages without installing globally
- Updating and auditing packages
- Publishing packages (overview)
2Working Example
💻 Example: npm & package.json
Terminal
▶ Run in Compiler
npm init -y
npm install express
npm install --save-dev nodemon
npm run dev💻 Continued Example
JSON
▶ Run in Compiler
{
"scripts": {
"start": "node src/server.js",
"dev": "node --watch src/server.js"
}
}3Best Practices & Common Pitfalls
💡 Key things to remember:
- Dependencies (--save, default) are needed to run your app in production; devDependencies (--save-dev) are only needed while developing (like testing tools).
- Semantic versioning: MAJOR.MINOR.PATCH — a bump in MAJOR usually means breaking changes.
❓ Frequently Asked Questions (FAQ)
Q What's the most important thing to understand about npm & package.json?
Focus on: npm init · npm install · Dependencies vs devDependencies · Semantic Versioning · npm scripts · npx. These are the core building blocks this chapter's examples are built around, and they show up repeatedly in later chapters of this course.
Q Do I need external npm packages for npm & package.json?
Only where explicitly shown in the code examples above (like Express, Zod, or Socket.IO) — otherwise, this chapter relies entirely on Node.js's own built-in capabilities.