50 topics and questions for front-end developer (react) interview in 2021

Hey guys,
Below is a list of questions & topics that any front-end developer should know in 2021 interviews.

1. Context api vs Redux
2. Explain how Redux works.
3. What is CORS?
4. Long polling vs Standard polling
5. Indexed db (storage)
6. Full duplex communication, Web sockets, Web socket handshake
7. Can I access state in redux action?
8. Class based vs functional components
9. What are the advantages of functional components?
10. Name a couple of hooks and what they are good for.
11. Explain useCallback
12. Lazy loading - explain and how to implement; name web pages as an example of lazy loading
13. What are the tools you use while developing web app.
14. Explain pagination, name web pages that uses pagination
15. package.log explain (.log vs package..)
16. Devdependencies vs dependencies
17. Minification uglification, mapping (source maps)
18. Monolith vs microservices
19. Advantage of micro services and microfrontends
20. Orchestration of micro services VS choreography of micro services
21. Oauth 2.0
22. Oauth (JSON webtoken)
23. Distributed tracing (time and correlationId)
24. How to customise 3rd party component?
25. How to implement component will unmount in a functional component?
26. What is an example for using component will unmount?
27. How to handle errors in React?
28. HOC (higher order component) - explain, how/why to use
29. React DOM - explain, how/why to use
30. Api interceptor/middleware - example
31. How to achieve responsiveness.
32. PWA - Progressive Web Application - explain
33. What is the library you use for unit testing?
34. How to troubleshoot web applications?
35. If the story is not clear how do you approach that?
36. How do you get familiar with a new code base?
37. What is SPA, and why is it important/good?
38. Difference between localstorage and cookie.
39. Can you create ErrorBoundary as functional component?
40. CSS variables
41. CSS display style
42. Responsive layout vs Adaptive layout (mobile)
43. What is PropTypes?
44. What is web pack?
45. What to test by unit tests on react component
46. What is render blocking code?
47. How to mock functions calls while testing with jest?
48. What is Prototype (in JS)?
49. Three different ways to check that the object is undefined.
50. How rest/spread operators works internally?

This list of questions was created with help of global technology platform.

Say in a comment what question should be added for .net developer interviews.