1. Explain the difference between var, let, and const in JavaScript.

2. What is a closure in JavaScript? Provide an example.

3. Explain the concept of prototypal inheritance in JavaScript.

4. How do you handle asynchronous operations using Promise in JavaScript?

5. What are the differences between callbacks and Promises in JavaScript?

6. How do you create and use generators in JavaScript?

7. Explain the concept of event bubbling and capturing in JavaScript.

8. How does the this keyword work in JavaScript? Provide examples.

9. What are JavaScript modules? How do you export and import modules?

10. What are higher-order functions in JavaScript? Provide examples.

11. Explain the concept of currying in JavaScript.

12. What are anonymous functions? Provide examples of their usage.

13. How do you use bind, call, and apply methods in JavaScript?

14. How do you handle errors and exceptions in asynchronous JavaScript code?

15. Explain the concept of event loop in JavaScript.

16. How does async and await improve asynchronous code readability in JavaScript?

17. What are the different ways to iterate over objects in JavaScript?

18. How do you implement inheritance using classes in JavaScript?

19. Explain the differences between Object.keys(), Object.values(), and Object.entries() methods in JavaScript.

20. How do you use Array.map() and Array.reduce() methods in JavaScript?

21. Explain the concept of memoization in JavaScript.

22. How do you implement a singleton pattern in JavaScript?

23. What are the differences between function declarations and function expressions in JavaScript?

24. How do you handle CORS (Cross-Origin Resource Sharing) in JavaScript?

25. What are Web Workers in JavaScript? How do you use them?

26. Explain the differences between synchronous and asynchronous JavaScript code execution.

27. How do you manipulate the DOM (Document Object Model) using JavaScript?

28. What are the differences between null, undefined, and NaN in JavaScript?

29. How do you implement a debounce function in JavaScript?

30. How do you implement a throttle function in JavaScript?

31. Explain the concept of lazy loading in JavaScript.

32. What are the differences between localStorage and sessionStorage in JavaScript?

33. How do you detect and handle memory leaks in JavaScript?

34. Explain the differences between == and === operators in JavaScript.

35. How do you implement data validation in JavaScript forms?

36. What are JavaScript design patterns? Provide examples.

37. How do you use fetch() API to make HTTP requests in JavaScript?

38. How do you handle cross-browser compatibility issues in JavaScript?

39. Explain the concept of hoisting in JavaScript functions and variables.

40. How do you use Regular Expressions (RegEx) in JavaScript?

41. What are the differences between ECMAScript and JavaScript?

42. How do you implement a queue data structure in JavaScript?

43. How do you implement a stack data structure in JavaScript?

44. What are the differences between Array.slice() and Array.splice() methods in JavaScript?

45. How do you implement memoization in JavaScript?

46. Explain the differences between strict mode and non-strict mode in JavaScript.

47. How do you handle date and time in JavaScript?

48. How do you implement deep cloning of objects in JavaScript?

49. Explain the concept of the Event Loop in JavaScript.

50. How do you use Object.assign() in JavaScript?