Tips for a Successful ReactJS Interview 🎉

Many of you may feel nervous and anxious when preparing for an upcoming ReactJS interview, right? Understanding this, I've written down a few notes. Hopefully, this will help you grasp the format of a ReactJS interview, what topics are commonly discussed, and boost your confidence. 🙂

AGENDA:

1. General reminders
2. Review JS/ReactJS knowledge
3. Practice algorithms
4. Research the company you’re applying to

Note:

• Each company has its own interview style, so use this as a reference, not a rule. 😉
• This guide is applicable to all levels: from junior to senior. The questions may vary in difficulty or scope based on your level.

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General reminders

A typical interview usually consists of the following parts:

• Introductions and greetings.
• Discussing your work experience, focusing on your most recent project.
• Problem-solving exercises:
  • Handling real-life work scenarios.
  • Coding exercises involving algorithms.
• Learning about your aspirations and expectations.
• Asking questions about the company or the projects you'll work on if hired.

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Reminders before and during the interview:

• Attire: Dress neatly, but there’s no need to overdo it. IT folks don’t need to look glamorous 😄. A simple outfit like jeans and a t-shirt works fine. No need for formal shirts. 😉
• Timing: Arrive 10-15 minutes early—not right on time. This gives you a moment to relax before starting. 😜 But don’t arrive too early either, like 30 minutes, as that might be awkward. 😅
• Contact: Ask for a phone number in advance so you can inquire about parking, elevators, the correct floor, etc., if needed.
• Attitude: Show a willingness to learn and explore new things. Avoid being rigid or saying, "I only know this; I don't want to explore new technologies." Such attitudes may not fare well.
• Stay calm and natural: This depends on individual mindset and isn’t easy to achieve. Take a deep breath, exhale, and try to stay calm. Be as natural as possible. If you need water, politely ask for a glass instead of staying thirsty and struggling to speak.
• Be honest: It’s impossible to know everything. If you don’t know the answer, be honest and say you’ll look into it. For example: "I find this very interesting, and if given the opportunity, I’ll definitely study and learn more about it." 😉
• Understand your own aspirations:
  • What do you want to do at this company?
  • Which technologies do you want to learn?
  • Are you aiming for a technical or management career path?
  • Do you have a personal plan to achieve your goals? If you don’t know what you want, how will you determine if the company is right for you?

1. Review JS/ReactJS knowledge

This is to prepare for questions about your most recent project. Depending on what you mention as your expertise, you’ll be asked related questions.

TIP: Don’t overstate your knowledge. If you’re asked follow-up questions, it may backfire. 😉

HTML/CSS

• Layout with flexbox or grid.
• Questions about UI libraries you’ve used: Bootstrap, Material Design, Ant Design.
• Layout design strategies.
• Given a UI design, explain how you’d implement it (conceptual, not coding).
• How do you organize styles in your project?
• What is BEM? How do you apply it?
• SCSS: What features have you used?
• CSS specificity.
• How to customize the styles of a UI library.
• Reset CSS vs Normalize CSS.
• ...

JAVASCRIPT

• "use strict".
• Differences between var, const, and let.
• Block scope vs Function scope.
• What is hoisting? This might involve explaining a code snippet.
• Closure.
• Value type vs reference type.
• Asynchronous JavaScript.
• setTimeout(), setInterval().
• Callback.
• Promise.
• Modules in JavaScript: import, export, etc.
• ES6 features: arrow functions, for...of, async/await, etc.
• Problem-solving scenarios using JavaScript knowledge.
• ...

REACTJS

• Component vs PureComponent.
• Lifecycle methods: which one to use for what purpose (check my YouTube channel for more on this 😉).
• Differentiate between component state, Context API, and Redux: when and why to use each.
• Refs in ReactJS: Have you used them? If so, for what purpose? If not, you might be asked to solve a problem using refs.
• Nested routing: What is it, and when is it needed?
• Setting up routing for pages requiring login.
• Which form management library do you use: Formik, Redux-Form, React-Hook-Form? Each has its own set of questions.
• Authentication: How do you handle authentication in an app? Token management, refresh tokens, expired tokens? (advanced topic).
• React hooks: Which hooks do you use, and for what purpose?
• Custom hooks: Have you written any? If yes, explain its purpose.
• Redux Toolkit: What is it?
• Facebook’s state management library Recoil: Have you heard about it? What are your thoughts? 🤣
• Common libraries you use in ReactJS projects.
• ...

2. Practice algorithms

This can vary widely, so it’s hard to predict the exact questions. Prepare thoroughly. Usually, the interviewer provides a problem, and you analyze it to find a solution.

• Basic search and sorting.
• Longest or shortest substring variations.
• Recursion.
• Finding a "mystery number" in an array meeting specific conditions.
• Graphs (rarely asked).
• Design patterns (e.g., Singleton, Observer).
• Code snippets: determine the output and explain.
• Dynamic programming (advanced, rarely asked unless the company specializes in algorithms).
• ... It depends on your logical skills.

3. Research the company you’re applying to

Learn about the company:

• What field does the company operate in?
• Company size?
• When was it established?
• Projects the company has worked on.
• Reviews about the company.
• ...

Ask about the project you’ll work on if hired:

• What is the project about?
• Technologies and tech stack used.
• Team size and who you’ll work with.
• Is the team friendly and collaborative?
• ... Ask anything you care about regarding your future team.

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I hope you find this guide helpful!
Wishing you a successful interview! 🎉