JavaScript Interview Questions

This is a very important guide for Beginner to Advanced JavaScript Interview QNA. These all questions are asked in real interviews via companies.

1. What is hoisting in JS?
2. How does JavaScript work?
3. What is the difference between let, var, and const?
4. What is an event loop?
5. Difference between Local Storage, Session Storage, and Cookies?
6. What are generator functions? to control the flow of execution and create iterable sequences of values? 
7. What is the difference between setTimeout and setInterval?
8. What do you mean by "rest and spread operator"?
9. What is meant by Shallow Copy and Deep Copy?
10. What are closures?
11. What is the difference between a promise and a callback?
12. What are arrow functions in JavaScript?
13. Explain About ES6 features?
14. What is the difference between the ES6 and ES5 standards?
15. What is currying in JavaScript?
16. What is a temporal dead zone?
17. What are Event bubbling and Event Capturing in JavaScript?
18. What is a mutation observer?
19. Falsy values in JavaScript?
20. Object.seal vs Object.freeze?
21. Explain Call, Bind, and Apply in JavaScript with examples.
22. Explain Higher Order Functions in JavaScript.
23. Explain Scope and Scope Chain in JavaScript.
24. What are Object Prototypes?
25. What are Callbacks?
26. What is the difference between PUT, POST, and PATCH?

27. What is IIFE in JS explain with an example.