Medium JavaScript Interview Questions

This section contains intermediate-level JavaScript interview questions. Click on each question to see its detailed answer.

1. Explain slice() and splice() methods of an array. ✅
2. What is event bubbling in JavaScript? ✅
3. What is the value of the "this" keyword in arrow functions? ✅
4. What are closures in JavaScript? ✅
5. What is recursion in JavaScript? ✅
6. What are higher-order functions in JavaScript? ✅
7. What is a callback function in JavaScript? ✅
8. What is the difference between synchronous and asynchronous programming? ✅
9. What is the difference between querySelector and querySelectorAll? ✅
10. What is hoisting in JavaScript? ✅
11. What are JavaScript promises, and how do they work? ✅
12. What is the difference between function declaration and function expression? ✅
13. What are JavaScript modules, and why are they used? ✅
14. What is the difference between shallow copy and deep copy? ✅
15. What are the different ways to iterate over an array in JavaScript? ✅
16. How does destructuring assignment work in JavaScript? ✅
17. What are rest and spread operators in JavaScript? ✅
18. What is the difference between call, apply, and bind methods? ✅
19. How do you handle errors in JavaScript using try-catch? ✅
20. What is the purpose of the new keyword in JavaScript? ✅