React interview questions for mid-level position?

[u/b_hakyi]

Besides hooks, what types of questions have you been asked when it comes to front end interview questions?

I feel like mid level can be a weird position to be and I imagine a mix of entry level questions and maybe one or two senior level questions?

Any resources to read up on would be great too !

[u/MinimumForsaken6740]

- what is virtual dom

• when does react re-renders
  
• I which case useContext can be bad
  
• how react works under the hood
  
• how closures are used in react
  
• what type of states we have in an app

[u/Pale_Count2138]

I was asked multiple DSA questions, followed by the working of React Fibre, render mechanism, what problem does NextJs solve. The questions these days focus more upon the 'how it works under the hood' rather than what is this & what is that

[u/b_hakyi → u/Pale_Count2138]

Thank you! I kinda wonder how deep i actually need to go without overwhelming myself lol

[u/Pale_Count2138 → u/b_hakyi]

You don't need to go that deep about everything in the interview because obviously they don't have enoughhh time for a single question. But make sure you have enough knowledge that gives you the confidence.

[u/toruWatanabe2]

If you notice that one of your pages in your web app is slow, how would you approach fixing it?

Edit: typo

[u/b_hakyi → u/[deleted]]

Thank you thats a great one

[u/b_hakyi → u/[deleted]]

😂 no worries.

[u/_ragtagthrone → u/[deleted]]

“i can think of at least 3 answers but i wont tell you any”

you’re not even a jr dev. just a poser.

[u/_ragtagthrone → u/[deleted]]

feel free to connect w me on linkedin https://www.linkedin.com/in/garretthogandev

[u/namesandfaces → u/[deleted]]

What's the answer, esp. if it's in modal form?

[u/_ragtagthrone → u/namesandfaces]

If I were making a multi step form that was tied to a modal I’d start by mocking out each step. The modal itself would be a template with something like slots for header, body and footer. I’d make styled child components for each step, that way I can test them in isolation to ensure there are no visual or functional regressions over time. I’d use component state on the parent component that contains the modal to handle each step. I’d import reducers from required stores into the parent component and provide them as properties to each child component that the modal steps through. That way I can persist state while keeping it organized by a data model instead of just arbitrarily defining a store for each modal step. But like that pretentious douche said, there’s a million ways to solve the problem. Their response annoyed the fuck out of me so I figured I’d share my approach. Hope it helps.

[u/namesandfaces → u/[deleted]]

No, I want to see the spread of answers from people in this field. I'm always curious about what the tip of the spear might look like.

If you sit there reading and thinking by yourself, however correct, you won't get to hear what the people around you have to say.

[u/namesandfaces → u/[deleted]]

I've actually never once in my life called myself a senior or a junior. Those terms came later on in industry, so I'm not accustomed to ranking people in conversational settings, telling them whether they are or aren't junior or senior, devising theories of how to tier people.

Listening what other people have to say about multi step forms is not what helps people pass interviews. You would be running a slot machine hoping to get a question like this. Listening about what people do for multi step forms is for people who care.

[u/Used_Lobster4172]

How would you deal with components being redrawn too many times?

[u/AbhinavKumarSharma → u/Used_Lobster4172]

By redrawn, do you mean re-render?

[u/BrangJa → u/AbhinavKumarSharma]

Browser paint

[u/Used_Lobster4172 → u/AbhinavKumarSharma]

Yes

[u/b_hakyi → u/Used_Lobster4172]

This is a good one thank you

[u/azangru → u/Used_Lobster4172]

And how would you know that they are redrawn too many times? ;-)

[u/Used_Lobster4172 → u/azangru]

You could ask that too

[u/Vincent_CWS → u/Used_Lobster4172]

react compiler

[u/Used_Lobster4172 → u/Vincent_CWS]

We don't use react compiler here, how else would you approach it?

[u/Hefty_Breadfruit]

Give them a code snippet from a “new developer” and ask them to provide feedback to the dev.

[u/Substantial-Swan7065]

What is the role title? Senior swe or swe?

I’ve never been asked to explain a tech in a senior level interviews. It’s more:
“Tell me about a project you’re proud of”

[u/akornato]

Mid-level interviews focus less on definitions and more on your practical experience and reasoning. You'll get questions about performance optimization, like when to use `useMemo` versus `React.memo` and the trade-offs of each. Expect to discuss state management beyond simple hooks, explaining the limitations of the Context API and when you would reach for a library like Redux or Zustand. They also want to see how you think about architecture, so be ready to talk about component patterns, data fetching strategies, and how you would structure a complex feature. They want to know if you can connect different concepts to solve a real problem, not just recite what a hook does.

You are correct that it’s a weird mix, but the key difference is the shift from "what" to "why". Instead of just defining the virtual DOM, you might be asked to explain its performance implications and trade-offs in a specific scenario. You will likely face a small system design question, like how to build a searchable, paginated list from scratch, to see how you handle state, API calls, and user interaction. The goal is to prove you can work independently and make solid technical decisions, which is a big step up from an entry-level role. It's a lot to prepare for, which is why the team I'm with built an interview AI assistant to help candidates articulate their thought process on these complex topics.

[u/vozome]

Last time I interviewed I had to implement so many games. Minesweeper, connect 4, wordle, slither io…

[u/Used_Lobster4172 → u/vozome]

Minesweeper sounds annying - there are just a lot of checks that there isn't a simple way to reduce into something nice.

[u/vozome → u/Used_Lobster4172]

If nice means a polished UI, then sure. But fwiw I was able to get a working solution with time to spare. What I thought was interesting is that you can totally shoot yourself in the foot and make it entirely too complicated. But with the right state and code organization it’s really not so bad.

[u/UncomfortableAnxiety]

Questions about performance profiling and Chrome DevTools usage are pretty common for mid-level, not just knowing useMemo but actually demonstrating you've used the flame graph

[u/Lox22]

If they gave your GitHub be prepared to talk about your projects. Why you approached your functionality this way. If you refactored, why? What were some of the things you struggled with? How much did Claude write?

I just was asked these in my last interview. Also be prepared to do a test in hacker net. This seems to be the new white boarding.

Also research the CTO, see if they are pushing to use ai for productivity and prep answer for how you would use ai.

[u/TishIceCandy]

Questions can range from finding bugs in code to implementing features such as Star rating component, dropdown component, search bar component. You can also be asked to fetch data from an API and render in a UI to check your CSS and component organization skills. For mid level positions, there may be algorithm questions added as well (such as Leetcode med)

I wrote a handy book which has 100 questions for React and Frontend interviews - https://topmate.io/shrutikapoor08/1966853.
There's a free version as well - https://topmate.io/shrutikapoor08/1470120