Web Development
Node.js Questions Comprehensive collection of the most frequently asked Node.js interview questions covering fundamentals, asynchronous programming, streams, clustering, security, and advanced concepts. Each answer is concise, detailed, and interview-ready.
1. What is Node.js? Beginner 2. How does Node.js work? Beginner 4. Why is NodeJS single-threaded? Beginner 5. If NodeJS is single-threaded, then how does it handle concurrency? Intermediate 6. Why is NodeJS preferred over other backend technologies like Java and PHP? Beginner 7. What is the difference between Synchronous and Asynchronous functions? Intermediate 8. What are the modules in NodeJS? Beginner 9. What is the purpose of the 'require' keyword in NodeJS? Beginner 10. What is V8 engine in Node.js? Intermediate 11. How to handle environment variables in NodeJS? Beginner 12. What is control flow in NodeJS? Intermediate 13. What do you mean by event loop in NodeJS? Intermediate 14. What is the order in which control flow statements get executed? Advanced 15. What are the main disadvantages of NodeJS? Intermediate 16. What is REPL in NodeJS? Beginner 17. How to import a module in NodeJS? Beginner 18. What is the difference between NodeJS and Angular? Beginner 19. What is package.json in NodeJS? Beginner 20. How to create the simple HTTP server in NodeJS? Beginner 21. What are the most commonly used libraries in NodeJS? Beginner 22. What are promises in NodeJS? Intermediate 23. How do you install, update, and delete a dependency? Beginner 24. Which command used to import external libraries? Beginner 25. What is event-driven programming in NodeJS? Intermediate 26. What is a buffer in NodeJS? Intermediate 27. What are streams in NodeJS? Intermediate 28. Explain the crypto module in NodeJS. Advanced 29. What is callback hell? Intermediate 30. Explain the use of the timers module in NodeJS. Intermediate 31. Difference between setImmediate() and process.nextTick() methods Advanced 32. What are the different types of HTTP requests? Beginner 33. What is the difference between spawn() and fork() method? Advanced 34. Explain the use of the passport module in NodeJS Advanced 35. What is a fork in NodeJS? Intermediate 36. What are the three methods to avoid callback hell? Intermediate 37. What is a .body-parser in NodeJS? Intermediate 38. What is CORS in NodeJS? Intermediate 39. Explain the tls module in NodeJS. Advanced 40. Can you access DOM in Node? Beginner 41. How do you manage packages in your NodeJS project? Beginner 42. What is the purpose of NODE_ENV? Intermediate 43. What is a test pyramid in NodeJS? Advanced 44. What is piping in NodeJS? Intermediate 45. What is a cluster in NodeJS? Intermediate 46. Explain some of the cluster methods in NodeJS Intermediate 47. How to manage sessions in NodeJS? Intermediate 48. How many types of API functions are there in Node.js? Beginner 49. How can we implement authentication and authorization in NodeJS? Advanced 50. Explain the packages used for file uploading in NodeJS. Intermediate 51. Explain the difference between NodeJS and server-side scripting languages like Python Advanced 52. How to Connect NodeJS to a MongoDB Database? Intermediate 53. How to read command line arguments in NodeJS? Intermediate 54. Explain the NodeJS Redis module. Advanced 55. What is web socket? Advanced 56. Explain the util module in NodeJS Intermediate 57. Explain DNS module in NodeJS Intermediate 58. What is the difference between setImmediate() and setTimeout()? Advanced 59. What is an Event Emitter in Node.js? Intermediate 60. What is a callback function in Node.js? Beginner 61. What are the advantages of using promises instead of callbacks? Intermediate 62. What is the difference between frontend and backend development? Beginner 63. What is I/O in Node.js? Beginner 64. How is Node.js most frequently used? Beginner 65. What are some of the pros and cons of Node.js? Intermediate 66. What is Express.js? Beginner 67. What is the URL module in Node.js? Intermediate 68. How would you use a URL module in Node.js? Intermediate 69. How can we use async/await in Node.js? Intermediate 70. What is JWT, and how do you implement it in Node.js? Advanced 71. What is the difference between require and import in Node.js? Intermediate 72. What does 'non-blocking' mean in Node.js? Beginner 73. How does Node.js overcome the problem of blocking I/O operations? Intermediate 74. What is TLS/SSL in Node.js? Advanced 75. How does Node.js differ from other backend technologies? Intermediate 76. How would you scale a Node.js application? Advanced 77. What are the best practices for error handling in Node.js? Advanced 78. Why does Google use the V8 engine in Node.js? Advanced 79. Why are Java developers increasingly adopting Node.js? Intermediate 80. Does Node run on Windows? Beginner 81. Why should you separate the Express app and server? Intermediate 82. Explain the concept of stub in Node.js. Advanced 83. What is the framework that is used majorly in Node.js today? Beginner 84. What are the security implementations that are present in Node.js? Advanced 85. What is Libuv? Advanced 86. What are global objects in Node.js? Beginner 87. What is ExpressJS used for? Beginner 88. What is the use of the connect module in Node.js? Advanced 89. What are LTS releases of Node.js? Beginner 90. What do you understand about ESLint? Intermediate 91. How does Node.js handle the child threads? Advanced 92. How to Enhance Node.js Performance through Clustering? Advanced 93. What is a thread pool, and which library handles it in Node.js? Advanced 94. How are worker threads different from clusters? Advanced 95. How to measure the duration of async operations? Advanced 96. How to measure the performance of async operations? Advanced 97. What are the types of streams available in Node.js? Intermediate 98. What is meant by tracing in Node.js? Advanced 99. Where is package.json used in Node.js? Beginner 100. What is the difference between readFile and createReadStream in Node.js? Intermediate 101. What is the use of the crypto module in Node.js? Advanced 102. What is a passport in Node.js? Advanced 103. How to get information about a file in Node.js? Intermediate 104. How does the DNS lookup function work in Node.js? Intermediate 105. What is WASI, and why is it being introduced? Advanced 106. What is a first-class function in Javascript? Intermediate