Do a quick search for 'Javascript Interview Questions' on Google, you'll get to know the reality. You'll get thousands of relevant results. Actually, not really relevant.

Fancy, Attention Grabbing:

"Top 100 Javascript interview questions"

"Commonly asked Javascript interview questions"

It might seem that you'll go through these 100 questions and you'll be ready for your interview. However, it won't take you much time to realise that you are just wasting your time.

Trust me I've been there many times, to find out that just a couple of them are good. Others are just useless. Many of these results just list down the most basic Javascript questions you would never be asked in your interviews.

"What is Javascript?"

"What are the features of Javascript"?

"What are the variable naming conventions in Javascript?"

"What is the difference between Java and Javascript?"

Do you think you'll be asked such questions in an interview? Nobody's going to waste the limited time they have to judge you on such questions. Not even in the screening rounds.

And personally if I am asked such questions in an interview, I would never join such a place. And I advice you should do the same. You would be wasting precious years of your career working on school grade projects at such places.

So most of these posts with attractive titles are nothing but attention and traffic grabbing posts. You'll end up going through 100s of these questions, just to realise you didn't learn anything new here.  This is very not just valid for the folks interviewing for senior positions, but also valid for junior developers.

You'll agree with me on how much limited time a candidate preparing for an interview has, especially with a job.

Rejections Made Me a Better Developer

I faced many rejections during the initial years of my career.

Believe me rejections are great. Rejections should never demotivate you. Every rejection moves you one step closer to your goal.

I've interviewed at many top Tech companies. I faced many rejections during the initial years of my career.

Now, I conduct interviews for top Tech companies.

I was not aware. My work did not give me an opportunity to work on bleeding edge Javascript, on libraries, on performance. I definitely lacked a lot.

And I did not know the interview expectations of top tech companies from a candidate. So I started interviewing for every company I got an interview call for. And know what?

I got rejected in about 10 of them, before I finally got an offer.

I did not join. But now I knew what different Tech companies want. Now I knew how to prepare for a Javascript interview. The following year I was able to crack a well know Travel Tech company at a single shot.

And you know what? Preparing for interviews made me a better Javascript developer, not my jobs.

Many of us have a similar stories. The work you do in your daily job might be different from expectations in an interview. But that should not stop you. You should not be dependent on it.

I've learnt that hard way, you don't have to.

What should I focus on for a Javascript Interview?

Here are a few things that you should focus on, for you Javascript interviews. I guarantee, you won't just crack the interviews, you'll become a better developer as well.

  • Vanilla JS: Focus on plain Vanilla Javascript. Knowledge of a framework - React/Angular is always secondary.
  • Core Concepts: Practice problems around core Javascript concepts - Hoisting, closures, functions, arrays, object, event loops, timers. Learn how to apply them.
  • Patterns: Have a knowledge of Javascript patterns.
  • Practice plugin development:  How can you create your own Javascript library - modals, accordions etc.
  • Know the ecosystem: Environment where Javascript runs - browser/server. How browsers work? How they render pages?
  • Javascript Tooling: Webpack, bower, rollup ... what they exactly do, why do we need them.
  • Testing in Javascript: Most ignored but one of the most important topics.
  • Performance: Making websites fast, making your code production ready, techniques like debouncing/throttling, lazy loading, virtualisation etc.
  • Utility functions: Ever used lodash or underscore? Practice implementing those utility functions.

Definitely not a complete list, but good enough to give you an idea what you need to focus on and what to ignore.

It hard to find a single source for good content on these different topics. The Javascript ecosystem is just too vast.

This website aims to solve that problem. We want to make quality Javascript interview preparation material available right here at a single place. So that you don't have to waste time reading a lot of books, going through multiple online sources and videos. At the same time, help you become at better Javascript developer.

I hope that was helpful. Don't forget to subscribe and share. We promise quality Javascript interview content delivered to your inbox.