Javascript Interview Questions(Divided into levels)
Tags: webdev, javascript, interview, codenewbie
Published: 2022-02-15 14:00:05

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> Today no code time to look for a job
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Ever went to apply for a Javascript job and got stuck on some of the areas to prepare for the interview? Boom Roy got you covered.  Check out. I just screened some of the common asked questions. Open to more on the comment section. Cheer!!! All the best
**Junior Dev Interview**

1. Explain Null and Undefined in JavaScript  

2. What does use strict do?  

3.  What is the strict mode?  

4.  Explain arrays in JavaScript.

5.  Explain Values and Types in JavaScript. 

6. What is Scope in JavaScript?  

7. What is difference between == and === ?
8. What is let keyword in JavaScript?  

9. What is the difference between var, let, and const. 

10. What are the JavaScript data types?

11. Explain the .pop() and .push() methods

12. Name all JavaScript’s Boolean logical operators

13. What is JSON

14. What are the .slice() and .splice() methods

15. What is the DOM? And what does it do?

16. What is a Polyfill?  

17. What are operators?

18. Explain .then keyword

19. Explain equality in JavaScript

20. What is typeof operator?  

21. Explain how Bubble Sort works
22. Given a string, reverse each word in the sentence
  
23. How to empty an array in JavaScript?
  
24. Explain what is a callback function?

25. Write a function that takes an array of integers and returns the sum of the integers after adding 1 to each

**All the best to Junior JS devs applying for new roles**


  
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Mid-Level Javascript Dev. Interview
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26. What is the definition of a Higher-Order Function?
  
27. Describe Closure concept in JavaScript 

28.  What are the advantages and disadvantages of using use strict?
  
29. What is the purpose of setTimeout function?
 
30. What is the new keyword in JavaScript?

31. 31. What advantages are using arrow functions?

32. What object.freeze() does? 
  
32. Explain the difference between Object.freeze() vs const

33. What is generator in JS?
  
34. How to remove duplicates from an array 

35. What is Currying?

36. What is IIFEs

37. 37. What's the difference between .call and .apply?
  
38. What is Coercion in JavaScript?
  
39. Explain what is Hoisting in Javascript? 

40. Write a program for Recursive Binary Search1210


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> Well we are done now its time for Big Boys Now

   

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  Senior Javascript Devs "BigBoy's"
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41. Write a program that checks if a given string is a palindrome and case sensitivity should be taken into account.

42. Write a program that Merges two sorted linked lists
43. Given an integer, determine if it is a power of 2. If so, return that number, else return -1
  
44. When would you use the bind function?
  
45. Write a recursive function that performs a binary search

46. Why is this operator inconsistent?
46. Explain how async and await work. 

47. Can you describe the main difference between a .forEach  and a .map()?

48. Explain what is Fibonacci Search technique?

49. Explain how QuickSort works

50. Implement a queue using a linked list

Cheers to your interview tests. 

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