What are some of the most commonly used libraries in Node.js?

Q: What are some of the most commonly used libraries in Node.js?

**ExpressJS:** Express is a flexible Node.js web application framework that provides a wide set of features to develop web and mobile applications. **Mongoose:** Mongoose is also a Node.js web application framework that makes it easy to connect an application to a database. **JWT:** json web tokens for authentication and authorisation **Puppeteer:** For web scraping and crawling.

Difficulty: 4/10

HTTP frameworks, ORM/DB libraries, testing utilities

1
ExpressJS: Express is a flexible Node.js web application framework that provides a wide set of features to develop web and mobile applications.
2
Mongoose: Mongoose is also a Node.js web application framework that makes it easy to connect an application to a database.
3
JWT: json web tokens for authentication and authorisation
4
Puppeteer: For web scraping and crawling.

Scenario Questions

0-2 years experience

1We're building a simple CLI tool in Node.js that needs to parse command‑line arguments. Which library would you reach for, and how would you use it?
2If you need to make an HTTP request to an external API in a small script, which library would you choose and why?
3You need to write unit tests for a tiny module. Which testing library would you pick and how would you set it up?

Follow-up Questions

What steps would you take to add that library to an existing project?
How do you keep the library up to date without breaking production?
Can you give an example of a situation where you’d choose a less‑common alternative?