React Handwritten Notes for Placements (Free PDF)

Most React interviews for freshers circle the same ten ideas: state vs props, the useEffect dependency array, keys, the virtual DOM, re-renders and memoization, Context vs Redux, and how you would speed up a slow page. These notes give each of them one page, with a small example and the trap that catches people.

What makes these React notes different?

• Built around interview questions. Pink boxes hold the questions that come up again and again, with answers you can say out loud.
• The traps that cost marks. Why setCount(count + 1) three times only adds one, why {items.length && <List />} prints a 0, and why your effect runs twice in development.
• Modern React. Function components and hooks throughout, React 18 and 19 features, and how Next.js fits in with SSR and Server Components.
• Hinglish where it helps. Reconciliation, context and lifting state get a short Hinglish explanation next to the English definition.

How should you use these React notes?

Create a small Vite app and run each snippet as you read. Try the output-based questions before looking at the answers, then use the last page as a one-page revision sheet before the interview.

This is Part 3 of the series. Start with the JavaScript handwritten notes if you want to revise closures, promises and the event loop first.

Ready to test yourself? Try the Top 50 React interview questions with answers, a free PDF with a short answer to say and a detailed explanation for every question.