Important Node JS interview questions to prepare for interview

chitaranjan biswal

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Sep 22, 2024

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Advanced Node.js Interview Questions:

1. Explain the event loop in Node.js and how asynchronous operations are handled.
2. What are streams in Node.js? Explain the different types of streams.
3. What is a buffer in Node.js, and how does it differ from a JavaScript string?
4. How does the cluster module improve performance in Node.js?
5. How do you use child processes in Node.js?
6. What are worker threads in Node.js? How do they differ from child processes?
7. How do you handle errors in Node.js, especially in asynchronous code?
8. How does garbage collection work in Node.js, and what are memory leaks?

Advanced Express.js Interview Questions:

1. Explain how middleware works in Express.js and the types available.
2. How does Express handle routing, and how can you use route parameters effectively?
3. How do you create custom error-handling middleware in Express.js?
4. How do you manage user sessions in Express?
5. How do you implement rate limiting in an Express.js application?
6. What strategies can you use for API versioning in Express.js?
7. How do you handle file uploads in Express.js?
8. How do you use a template engine with Express.js?
9. How do you integrate WebSockets (using Socket.IO) with an Express.js server?
10. How do you test an Express.js application, and which libraries do you use?
11. What is CORS, and how do you handle it in Express.js?

General Node.js and Express.js Interview Questions:

1. What is Node.js, and how does it differ from traditional web server technologies?
2. Explain the difference between synchronous and asynchronous functions in Node.js.
3. How can you avoid callback hell in Node.js?
4. How does Node.js handle file I/O operations?
5. What is the purpose of the package.json file?
6. What are Promises and async/await in Node.js?
7. Explain the concept of middleware in Node.js applications.
8. How is Express.js different from other Node.js frameworks?
9. How do you structure a large Express.js application?
10. Explain the difference between res.send() and res.json() in Express.js.
11. How do you handle errors in Express.js?
12. What are the differences between GET, POST, PUT, and DELETE requests in RESTful APIs?

Additional Advanced Node.js Questions:

1. What is the libuv library and how does it support Node.js?
2. What is the role of the V8 engine in Node.js?
3. How do you debug a Node.js application?
4. What are Event Emitters in Node.js, and how do they work?
5. What are the differences between process.nextTick() and setImmediate()?
6. Explain the role of the REPL (Read-Eval-Print Loop) in Node.js.
7. What is the use of the npm (Node Package Manager), and how do you manage dependencies in a Node.js project?
8. Explain how you would handle database interactions in Node.js.
9. How do you handle concurrency in Node.js?
10. What are Web Workers, and when would you use them in Node.js?
11. How would you manage long-running processes in Node.js?
12. What are the benefits and drawbacks of using WebSockets in a Node.js application?
13. What is the difference between app.use() and app.get() in Express.js?
14. How do you handle request and response timeouts in Express.js?
15. What is the difference between res.redirect() and res.forward() in Express?
16. How do you serve static files in Express.js?
17. How would you implement authentication and authorization in an Express.js application?
18. What is the purpose of using helmet in an Express.js application?
19. How would you implement logging in an Express.js application (e.g., using morgan)?
20. How do you scale an Express.js application to handle heavy traffic?
21. How do you implement file download functionality in Express.js?
22. How do you handle multipart form data in Express.js?
23. What are some best practices for optimizing the performance of an Express.js application?
24. What is the difference between using body-parser and express.json() for parsing request bodies?