Interview questions for JS
Published: 2021-11-26 05:32:10

![Javascript Interview Questions](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/n8jr92rc5beq630cclcv.png)




## Javascipt is a great language and i believe every web developer in todays world should definitely learn it.

Not is it just awesome but also by just learning and understanding javascript you will be able to learn and use so many great frameworks that are buzzing in current job market 
like  **React** , **Angular** , **Next JS**  etc.

> So this is a gist of some of the questions and concepts that i have came across in my interview for some product based startups.

**Basics**

Basics of javascript should be clear very much , Things like arrays , objects , variables etc should be very clear before even you think of applying at any job as a js dev.

**Arrays**

Arrays are very important and since you will be using them so much in your day to day use case as being a web dev you should definitely learn all the things that can be done in js for arrays like 
     * Push
     * pop
     * shift
     * unshift
also you should learn how we iterate over arrays 

> Also learn these :-
      * Slice
      * Splice

**Objects**

Every developer in his day to day life will definitely come across objects while working on a javascript project .
So every interviewer expects you know the basics of Objects.
 
Try to understand them and apply them in any of your projects.

Objects will also be used while you work on things like json all that is is a big blob of object so you have to work with them .

So try to understand all related topics to objects 
Things like how we add an item to an object
  * How to iterate through an object
  * How can we delete an item from an object

> Try to also learn things like object.keys , object.freeze etc.

**More Good Topics**

> Every interviewer will ask you questions related to these questions so its very necessary that you know these concepts and can explain them in detail 

1. Whats Execution context in js.
2. Whats a promise and how to create one .
3. What are callbacks 
4. whats async/await used for 
5. Difference between == and ===
6. whats call , apply and bind .
7. Difference between simple functions and arrow functions
8. Whats 'this' in javascript
9. What are closures 
10. whats memoization
11. what is an IIFE(Immediately Invoked Function Expression).
12. Difference between let and Var.
13. Different stages of a promise.
14. Difference between setTimeout and setInterval

> There are other topics also which you should give a good go before going for the interview , not everyone will ask you these but its good to know them 

  1. Whats prototype and prototypal inheritance
  2. what are anonymous functions
  3. Event bubbling and how do you prevent that.
  4. Whats promise.all
  5. whats a polyfill.

There are many many topics in javascript that you would to know but for a fresher js or even for 1+ year of experience these are the most asked questions .
You can also checkout the greats series by [Akshay Saini](https://youtu.be/pN6jk0uUrD8) which explains all the javascript concepts in great detail.

All right , i guess this will be hopefully helpful for any one out there .

*Feel free to reach out to me for any thing over email*
[junaid shah](https://linktr.ee/jshahcodes)