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Kristiyan Velkov
Kristiyan Velkov

Posted on • Originally published at kristiyanvelkov.substack.com

My new book: Mastering React.js Interviews - From Zero to Hero

This book is your complete roadmap to acing React.js 19 interviews - from junior-level questions to mid-level mastery.

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Whether you're just starting out or preparing for your next big opportunity, this guide is built for you.

🎁 Launch Discount (Limited Time) 🎁
Get it now for just $20 (original price $30)

 👉 https://leanpub.com/masteringreactjsinterviews/c/Z1nOuw9zLGj8


Based on 350+ real-world front-end interviews, it delivers the most relevant technical questions asked by top companies - along with clear, practical answers that help you build confidence, deepen your React.js knowledge, and prove your skills where it matters most.

🔍 What's Inside?

  • Core React Concepts - JSX, Virtual DOM, props, state, and component structure (React.js v19)
  • Hooks Deep Dive - useState, useEffect, useReducer, useRef, useMemo, and more (React.js v19)
  • Performance Optimization - Avoid re-renders, lazy loading, memoization, and profiling (React.js v19)
  • Component Design & Reusability - HOCs, render props, children, and Fragments (React.js v19)
  • Forms & Event Handling - Controlled/uncontrolled components, validation, synthetic events (React.js v19)
  • Styling Techniques - CSS Modules, Tailwind CSS (v4.0), clsx (v2.1), and scalable styling strategies
  • Routing - Nested routes, useParams, useSearchParams, and route protection ** (React Router v7.4)**
  • Error Handling - Error boundaries, debugging practices, graceful fallbacks (React.js v19)
  • Global State Management - Context API (React 19), Redux Toolkit (v2.6), Zustand (v5.0), and best practices

Who This Book Is For

  • Junior Developers - Build a strong foundation and get interview-ready
  • Intermediate Developers - Deepen your skills and prepare for more challenging interviews -** Mentors** - Help your mentees go further, faster

Why I Wrote This

I've personally conducted 350+ React.js interviews as a front-end technical lead. I've seen where developers struggle and what separates successful candidates from the rest.
This book is built from that real experience, with no fluff, no copy-paste from docs, and no outdated patterns.
Just practical, clear, and modern content - designed to help you stand out.


🎁 Get it now for just $20 (was $30)🎁
 👉 https://leanpub.com/masteringreactjsinterviews/c/Z1nOuw9zLGj8


If you've ever felt overwhelmed by vague interview questions or unsure of how to explain core React concepts - you're not alone. This book is for you.

Thank you to everyone who supported me during this process. Your feedback, encouragement, and belief made this possible. 🙏

Let me know what you think of the book, and feel free to share it with someone who's preparing for their next React.js role!


© 2025 Kristiyan Velkov. All rights reserved.

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