Favorite Front-end/UI developer interview questions?

coffeecraftcode profile image Christina Gorton ・1 min read

Hey Dev community! Hit me with your favorite front-end/UI developer interview questions.

HTML, CSS, JavaScript, Accessibility etc.

Helping a student today prep for a final interview 🙏


markdown guide
  • How does a browser request for resources; what are verbs and the fundamental headers (content-type, cors & origin issues)?
  • What is hoisting? How does it impact code execution?
  • What are closures? Common applications?
  • What's the reason behind the infamous behaviour of this? Why we have to bind it?
  • Arrow functions vs function expressions, what's the practical difference other than the syntax?
  • Why do we call functions 1st class in JavaScript?
  • How do you listen for events in JavaScript, and how do you deal with bubbling and unwanted side effects?
  • == vs ===. Why we want to avoid == as possible?

  • Common issues with accessibility: nonsemantic HTML, handling focus, contrast ratios and color blindness

  • "Controlled" vs "uncontrolled" HTML elements

  • Semantic tags?


A lot of these are great but come from a line of 'traditional' / 'booksmart' thinking..
which is great for probing and making sure candidates have the knowledge behind knowing how to answer the question... but for a lot of these i'd accept an "i don't know, but i'd look at the API docs for this method/class and learn how to manipulate the js object or function to my need"

yakno? js evolves so quick; knowing the fundamentals of OOP + quick absorption of docs + knowing how to quickly iterate = a winner


I was mostly pointing out the common ones for front enders.

The memorable ones from my last interview were also:

  • how do you approach this one project, where do you start, what's your thought project

  • how do you deal with a colleague that won't give up an idea that you find very wrong

  • will you trust your boss decisions even if you won't always get the entire picture

I don't know if you can "study" these

Sloan, the sloth mascot Comment marked as low quality/non-constructive by the community View code of conduct

The boss one is a red flag to me. Will you be a good slave?

Spoiler alert: yes it's a red flag

But also I'm always kinda stupid and overwork myself


OOP is mostly a disservice to producing quality code


Oh wow, I realized that I know the answer to ALL these questions!! That's amazing!

  • Please estimate how long it would take to build this webapp based on these requirements?
  • What if you only have half an hour?
  • Let's build it. Now. Together.

This gives us insight in how you handle challenges and if you can prioritise the features that bring value.


Assuming they'd be expected to know about the "virtual DOM", popularized by React and others, asking why the virtual DOM is needed and how it generally works high level.


"Do you agree that React is massively overused and is basically like using a sledgehammer to crack a nut in most cases?"


😛 Certainly, but how they respond would reveal a lot


What is the difference between the focus and the caret ?
(Actually I use that question when I am grilled by people who know a js framework very well, have very limited frontend knowledge and try to establish a position of dominance. )


I was given an object and asked to create a copy.
I happily said Object.assign...
So these there the follow ups that screwed me over-

  1. What if it has nested objects, then Object.assign wont deep clone it. (where i answered with a loop to resolve this issue)
  2. What if there is a cyclic dependency? (I was stuck, but the interviewer insinuated to the tortoise-hare algo of two pointer solution to crack the cyclic dependency, although i still dont think that will help).

Note- I was to answer in VanillaJS, so answers like Lodash deep clone wouldnt work.
Anyways, I went back and learnt a lot while exploring this concept.


How would you make a basic grid?


Unless you were using it to display tabular data I wouldn't use


Also if somebody was asked a UI design question- please put that up as well! Christina, can you ask for this in your post as well? Some companies give you a days time to design a mock website. Such questions would help too!

  1. The famous setTimeout question.(event loop)
  2. Variable and function hoisting.

Do you think that tools like Webpack, SASS or jQuery made us to use them even for a single landing page? And what would you do to avoid it?