JavaScript interview questions

1. What is ES6?
2. Features of ES6?
3. Difference between var, let & const
4. What is object in JavaScript?
5. What is literals in JavaScript?
6. Difference ways to create object in JavaScript?
7. What is ‘this’ object in JavaScript?
8. What is prototype?
9. Do you know inheritance? Do we have inheritance in JavaScript? How to use it?
10. What is closure? Give an example?
11. What is callback? Give an example?
12. Do you know callback hell? Please explain?
13. What is apply, bind & call?
14. What is filter & map?
15. What is map & set?
16. List the array functions(methods)
17. What is deep & shallow copy? Difference between both?
18. What is RxJS?
19. How many operators are there in RxJS?
20. What is forkjoin?
21. What is an observable?
22. What is subject behaviour?
23. What is promise?
24. What is async & wait? Explain with example?
25. Difference between promise & async-await?
26. How do you handle nested promise call?
27. What is difference between setTimeout & setInterval?
28. What is constructor?
29. Explain me types of access modifier?
30. What is singleton class?