Javascript Popular Interview Questions | Flashcards.js

A system to prepare for an interview

To get 80% of the results for 20% of the effort you must focus on the most popular interview questions. I've been a professional interviewer, and I went through 50+ interviews to figure out what is truly important for decision-makers. Every question became a little flashcard, and now I have 162 of them.

Most frequently asked questions

Focus on things that interviewers actually ask! Start with the first 50 high-frequency questions, and you will do better than most of other candidates. Save time and keep focused.

Check if you're ready

Are you sure that you know everything about asynchronous calls, closures, prototypes? I’ve split the cards into six groups covering all aspects of JavaScript. Checking your progress is much easier with physical cards, than with a book, app or website.

Support from an expert

The flashcards also come with access to a two-hour webinar, where I will also cover the non-technical and soft-skills related aspects, such as how to properly behave in the interview and how to answer some of the trickier personal questions.

Questions on the cards

The questions come from three sources: questions that interviewers look for on Google, questions that interviewers asked me during my interviews, and questions constantly reported by other developers.

Questions that interviewers search for in Google

8 out of 10 interviewers I asked confessed to have googled the phrase “frontend interview questions” or “js interview questions” and later asked the questions during the interview. I even did it myself when I was interviewing people for our company!

Questions that interviewers kept asking me

I went to about 50 interviews looking for the top interview questions. At some point, interviews became rather boring, because they all repeated themselves, I got a lot of questions that were EXACTLY the same.

Questions reported by other developers

I have a huge network of friends who got hired in solid companies, and they regularly provide me with the new questions. A lot of the stuff that the interviewer wants you to know is the same from company to company.

See in action
Question side of the Flashcards.js card
Answer side of the Flashcards.js card
Four Flashcards.js cards near red mug, notebook and laptop

Meet the author

Yuri Katkov, the creator of Flashcards.js

I am a JavaScript developer who loves teaching.

I was a Google Summer of Code mentor, taught students at universities, organized schools on web technologies and participated in Massive Open Online Courses. Born and raised in a small mining village in Russia, I moved to Switzerland to work for the most famous neuroscience project in the world and snatched a six-figure job because of my skills and my learning methods. I interviewed and hired many developers, so I know the ins and outs of the interviewing process. I teach programming courses and I understand your pain.

Anyone going to a job interview has experienced that terrible moment when they realize that the questions they are being asked do not match the things they had prepared for. This can be doubly painful because you know that you are the most qualified candidate for the job, yet you are unfortunately faced with questions that are simply not related to things you prepared for.

That's why I decided to look in other fields, like language learning, and came up with a simple method to prepare for an interview.

I tried to study popular books, but quickly realized that they're only useful when you want to be hired at Google and Facebook-like companies. Regular companies don't care about how good you are with algorithms; they ask entirely different questions.

Expert opinion

Daniel Gonik

Daniel Gonik

Senior Frontend Developer

"As a professional developer, you must know the answer to every question from this resource! I like the approach, instead of memorizing random facts, it provides a solid system for learning."

Evgenii Golubev, senior frontend developer

Evgenii Golubev

Senior Frontend Developer

"I've been working as an IT-recruiter for already two years. I tried the Essential pack and was surprised to find that the questions there are exactly the same that I usually ask the candidates. The questions are categorized and the learning experience is really fun.."

Andrew Shapel

Andrew Shapel

Works as Senior Developer

"I use this method to prepare junior and mid-level developers for technical interviews. It allows to concentrate on core abstractions of the language and the way the browser works. I also found it useful to use these cards as an interviewer."

Happy users

My method already helped people to get the jobs they had dreamed of.
Anastasia Kim

Anastasia Kim

Became a Mid-Level Developer

"Job interviews may be quite a lottery when you don’t know what they really expect from you. Yuri’s Flashcards system has actual questions and solid general answers on them, they showed me the vector of what the world needs and what I should study."

Eugene Gostyukhin

Eugene Gostyukhin

Got a senior developer position

"Awesome! This course saved me a lot of time. With flashcards.js I was able to focus only on topics which are truly important during the interview. And it led me to tremendous results: I got offers from all companies which interviewed me!"

What you will get

Essential deck

A deck of 50 most frequently asked interview questions:

  • Suitable for most interviews
  • 7 categories that cover the main areas of JS
  • An invitation to two-hours webinar on tactics and soft skills
Ultimate deck of Flashcards.js

Ultimate deck

A deck of 162 cards:

  • Includes all the cards of the Essential deck
  • Additionaly includes niche questions
  • Helps you to prepare for a wide range of interviews
  • Includes an invitation to two-hours webinar on tactics and soft skills
A man is preparing for Javascript job interview using Flashcards.js

A 20 hours course

A piece of my personal time spent entirely on you:

  • Cards are included
  • I will personally train you and share everything I know
  • Lots of practical tasks and drills on every lesson
  • Help with building your CV and GitHub account


  • Q: What's the difference between the Essential and the Ultimate deck?

    A: Essential deck consists of the most frequently asked interview questions. Ultimate deck has all the questions as the Essential one, plus more special questions that are still popular among interviewers.

  • Q: What don't you create a mobile app with these questions?

    A: The paper form has its own advantages. Mainly it's the fact that you can see more than one card at the same time. For example, you can put 50 cards on a table to quickly review your knowledge. The deck of cards is as portable as mobile app and can be a cool game to play with your geek buddies. Some of my clients use the cards during the interviews when they need to pick a good candidate in their teams.

  • Q: What kind of companies can I target after studying the questions from the cards?

    A: Regular American and European companies with decent salaries. I don't prepare you for Palantir, Twitter and Google interviews - these guys want too much knowledge about algorithms. The majority of regular companies don't ask algorithmic questions: if you know what's hash table and what's a tree, you're pretty much covered.

  • Q: Will it help me to prepare for Google/Facebook interview?

    A: Yes, but it will not be enough. In addition to the questions I have in the cards, companies from Silicon Valley love algorithmic questions, there's plenty of materials out there to prepare for interviews with these companies.

  • Q: What’s the webinar about?

    A: It's about teaching you how to demonstrate your soft skills: how you should behave, what should you answer if they ask you about your previous job or wage, how to describe your work experience to produce that much needed wow-effect.

  • Q: How long will it take to receive the cards?

    A: In Europe it will take from two days to a week if you use free shipping. For North America, it will take longer, consider using DHL if you need to prepare for an interview right away.

Flashcards.js A deck of Flashcards.js, the answer side is up