60 non-standard Node.js interview questions for Node.js system developers

This is the second part of the interesting set of non-standard Node.js interview questions for Node.js developers which were created by Timur Shemsedinov (CTO at QOTEQ, Salucyber, Metatech; Architect at Metarhia and Metactos; Lecturer at KPI, KSE). This 60 questions are for system Node.js developers only. But from my point of view you can use these questions during the interview and for preparation for the interview for backend developers for checking the deep knowledge of the Node.js of each developer.

Today I am publishing the second part - 60 questions for Node.js system developers.

1. What is the lack in ESM but it exists (support) in CJS?
2. Why do we use new Error.captureStackTrace?
3. Why is Node.js single-threaded? Prove Node.js has never been single-threaded.
4. Relationship between node:asynk_hooks and AsynkLocalStorage.
5. What tools inside Node.js do you know for binary serialization (the same as JSON)?
6. How can you watch for changing files or folders on a disk, and what problems can we have?
7. What will you use instead of deprecated fs.exists and why does the Node.js community want to delete it from Node.js?
8. What is a back pressure for a stream, and what problem will we have without one?
9. How can you protect SharedArrayBuffer from writing from different worker_threads?
10. Prove that any Node.js module during the loading becomes a function and creates a closure.
11. Where do we use the pattern Revealing constructor in Node.js?
12. How can you override write for Writable instance without creating a subclass?
13. What is the reason for the slow calls from JavaScript code to C, C++ addons or which are connected via N-API?
14. What is MessagePort and BroadcastChannel?
15. What is the difference between fs.stat, fs.fstat, fs.lstat?
16. Why is it important to use the rule eslint: consistent-return considering v8 optimization?
17. Why does WASI exist in Node.js and which opportunities does it give?
18. What can be done with help node:vm (any examples)?
19. Which deprecated API do you know and what is the strategy to phase them out?
20. Which problems, bugs, bottlenecks in Node.js do you know?
21. Explain how we can realize (or realize) async adapters promisify and callbackify?
22. Why does the event loop have phases? Why is it not enough to have only one queue?
23. What is the difference between macro and micro tasks?
24. What's special about the processing of uncaught exceptions in Node.js?
25. Why timers, sockets, servers and other similar classes have ref() and unref()?
26. What is the difference between nextTick, setImmediate and setTimeout?
27. Why is the server.connections deprecated and how can we get a connection without using one?
28. Tell the most common cases for memory leak and how to prevent them.
29. What is the difference between node:cluster and node:child_process? In which cases using the node:cluster is a bottleneck?
30. In which cases we need to shut out running garbage collection automatically and run one manually?
31. Which ways of debugging the Node.js applications do you know and when do you use one?
32. How can we clear require cache for a certain library? What do we do with ESM?
33. Where do the identifiers __dirname, __filename, require, import, fetch and Array exist?
34. Why do we need not to use the node:url library?
35. Which of the strategies of the scaling Node.js applications do you know? Can you compare them?
36. Which are the differences between cpu-intensive, ram-intensive and io-intensive tasks? Take some examples.
37. Why do we need no to use process.on(‘multipleResolvers’, handler)?
38. Tell, please, why does onDelay option need for the servers and the method setNoDelay for request and sockets?
39. How does the keep-alive work in HTTP protocol and how can we manage one from Node.js?
40. Why do we need the node:perf_hooks module? Can it work with workers?
41. What do you think about the experimental API for iteration methods (filter, map, reduce...) for streams?
42. Which ways for internationalizing Node.js applications do you know?
43. Do you use the built-in test runner and the node:assert library?
44. Which keys do you use when running node.js applications?
45. How can you create a dump of the V8 Heap and what will you do with one?
46. How can we create the flame graph?
47. Tell me about ALPN and SNI and their support in Node.js.
48. How can you realize a process reload automatically by native Node.js ways during code changing?
49. Why do we need a node:module?
50. How can we work with self-signed SSL certificates? Can you tell what the restrictions are for it?
51. Why do we have Web Crypto API in Node.js and which are the differences with node:crypto?
52. Why do we have Web Streams API in Node.js and which are the differences with node:stream?
53. Why do we have Blob and File classes from node:buffer?
54. What are the differences of the models of the access rights of the module:based and process-based?
55. What and why were deprecated in node:async_hooks?
56. Why do we need the AsyncResource class and how to use one?
57. How can you find all calls of the deprecated API in a Node.js application?
58. How can you work with dependencies in a single executable?
59. Do you know about problems with native test runner in Node.js?
60. Which have the new JavaScript features appeared in Node.js when you updated Node.js version to 18 or 20?