Node.js is a JavaScript runtime built on Chrome's V8 engine that allows you to run JavaScript on the server-side, enabling development of scalable network applications.

npm (Node Package Manager) is the default package manager for Node.js, allowing developers to install, manage, and publish JavaScript packages and dependencies.

What is middleware in Express?

Middleware functions in Express are functions that have access to request and response objects, can modify them, end the request-response cycle, or pass control to next middleware.

Node.js Interview Questions

41. What tools help profile memory usage in Node.js?

42. What is heap memory versus stack memory?

43. What are closures and how can they cause memory leaks?

44. What are timers in Node.js?

45. How do setTimeout and setInterval work internally?

46. What are common timer-related pitfalls?

47. What are modules in Node.js?

48. What is the difference between CommonJS and ES Modules?

49. How does module caching work in Node.js?

50. What are circular dependencies in modules?