Gaurav Tiwari’s Post

🚀 React Revision Notes for Interviews (PDF) After sharing my JavaScript notes, I created a React revision PDF to quickly revise important concepts before interviews. 📌 Topics Covered: ✔️ JSX & Components ✔️ Props vs State ✔️ Hooks (useState, useEffect, useMemo, useCallback) ✔️ React Router (Link, NavLink, useNavigate, Protected Routes) ✔️ Performance Optimization ✔️ Lifecycle & Virtual DOM 💡 Designed for quick revision (especially before interviews) 📄 Comment “REACT” and I’ll share the PDF OR Download here: https://lnkd.in/ddURrNSQ #reactjs #javascript #frontenddeveloper #webdevelopment #interviewprep #coding

🚀 React Interview Question: How do you optimize React Context to reduce unnecessary re-renders? 💡 React Context is a common way to share data across components But if it’s not handled carefully, it can lead to extra re-renders, whenever the context value changes, all the components using it re-render. 🔹 1. Split your Context Don’t put everything in one place - keep contexts small and focused for better performance 🔹 2. Memoize the value Context updates are based on reference changes. - use useMemo to keep the value stable 🔹 3. Avoid inline functions New function creates a new reference, which causes a re-render - use useCallback 🔹 4. Use selector pattern Don’t consume the entire context if you only need one value 🔹 5. Keep state local when possible Not everything needs to live in Context 🔹 6. Use React.memo Helps prevent unnecessary child re-renders 🔹 Key Insight: React Context doesn’t check deep changes It only checks if the reference has changed So to optimize: - keep values stable - split contexts smartly - avoid unnecessary updates Connect/Follow Tarun Kumar for more tech content and interview prep #React #FrontendDevelopment #JavaScript #WebDev #SoftwareEngineering #CodingInterview

One thing that confused me a lot when I started with React - Why does useEffect behave differently each time? 🤔 It all makes sense once you map it to class lifecycle methods. Whether you're learning React or prepping for interviews - this one's for you 👇 🔖 Save this for later. Follow for more. #React #ReactHooks #useEffect #FrontendDevelopment #JavaScript #WebDevelopment #ReactInterview #SoftwareEngineering

Frontend Interview Series: useState Sync vs Async? ⚛️ Today, I revised another important topic that often confuses developers in interviews: Is useState synchronous or asynchronous? The Reality: useState is not strictly asynchronous, but it behaves like it. When you update the state, React doesn't change the value immediately. Instead, it schedules an update to re-render the component. Why does this happen? It’s because of Batching. React groups multiple state updates together into a single re-render to keep the performance high. The Solution: To handle this, we can use the Functional Updater setCount(prev => prev + 1) for correct calculations, or useEffect to perform actions after the state has successfully updated. Mastering these core concepts is what makes a difference in technical rounds! #FrontendDevelopment #ReactJS #JavaScript #WebDevelopment #InterviewPrep #LearningInPublic #SoftwareEngineering

Top 10 React Hooks Interview Questions 1. What are the benefits of using Hooks in React? 2. What are the rules of React Hooks? 3. What is the difference between useEffect and useLayoutEffect in React? 4. What does the dependency array of useEffect affect? 5. What is the useRef hook and when should you use it? 6. What is useCallback? 7. What is the useMemo hook in React and when should it be used? 8. What is the useReducer hook in React and when should it be used? 9. What is the useId hook in React and when should it be used? 10. How to create and use Custom Hooks in React? Connect/Follow Tarun Kumar for more tech content and interview prep #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #ReactHooks #CodingInterview

🚀 Top 50 React Interview Questions – Must Prepare! 🔹 Preparing for a React interview? Focus on the fundamentals + real-world concepts: • What is React & how it works (Virtual DOM) • Functional vs Class components • Hooks (useState, useEffect, useContext) • Props vs State • Controlled vs Uncontrolled components • Lifecycle methods • Conditional rendering & lists • Forms & event handling 🔹 Level up with advanced topics recruiters love: • useMemo, useCallback & performance optimization • Context API vs Redux • Code splitting & lazy loading • Custom hooks • Error boundaries • React Router & navigation • API handling (fetch/axios) • Testing basics (Jest) 🔹 Pro tip: Don’t just memorize—build projects! • Create real apps • Explain your decisions • Be confident with debugging 💡 Master these, and you’re interview-ready! Source:- Respected owner ✨ Learn more from w3schools.com ✨ #ReactJS #WebDevelopment #FrontendDeveloper #CodingInterview #JavaScript

When I see such great posts on my timeline, I can't help but share them. If you are interested in React, you should definitely check it out. Even if you've already mastered React, it's good to revise and achieve next levels of your React Mastery.

🚨 Most Developers Get This Wrong in React Interviews 👉 Why does a component re-render even when nothing changed? If you can’t confidently answer this… You’re not ready for product-based interviews yet. 💡 React is not just about writing components. It’s about understanding: ⚡ How rendering works ⚡ Why performance issues happen ⚡ How to control re-renders 🔥 Real interview scenarios companies ask: • Why does a child re-render when parent updates? • Why do inline functions cause re-renders? • When does React.memo fail? • useMemo vs useCallback — real difference? • Why does useEffect run twice in React 18? ❌ Most people memorize hooks ✅ Top candidates understand behavior 📄 So I created: 👉 React Re-render & Performance – 30 Scenario-Based Questions This is NOT theory. These are the actual patterns interviewers test. 💬 Comment REACT and I’ll share the PDF #reactjs #frontenddeveloper #javascript #codinginterview #webdevelopment #softwareengineer #reactperformance #learnincode #techcareer #developers #react18 #programming 🚀

💡 React Interview Questions I Prepared as a Developer While preparing for interviews, I compiled a list of important React questions into a PDF 📄 Instead of keeping it to myself, I thought of sharing a quick summary here 👇 🔹 What is React? A JavaScript library for building UI using reusable components. 🔹 What is Virtual DOM? React creates a virtual copy of the DOM and updates only the changed parts → faster performance. 🔹 What are Hooks? Functions like "useState", "useEffect" that let you use state and lifecycle features in functional components. 🔹 What is State vs Props? State → managed inside component Props → passed from parent to child 🔹 What is useEffect? Used for side effects like API calls, subscriptions, timers. 🔹 What is conditional rendering? Displaying UI based on conditions (if/else, ternary). 🔹 What is key in React? Unique identifier for list items → helps React optimize rendering. 🔹 What is lifting state up? Sharing state between components by moving it to a common parent. --- 📄 I’ve attached my full PDF with more questions and explanations. Feel free to check it out! #ReactJS #FrontendDevelopment #WebDevelopment #MERNStack #InterviewPrep #LearnToCode

🚀 React Interview Question: What is the useRef hook and when should you use it? 💡In React, useRef is a hook that lets you store values that persist across renders — without triggering a re-render. 🔹 Key Idea: useRef returns a mutable object with a .current property that you can update anytime. 🔹 Use cases: Access DOM Elements - perfect for focusing inputs, scrolling, or measuring elements. Store Mutable Values - keep values like counters, timers, or flags without re-rendering. Persist Previous Values - track previous state or props easily. 💡 Interview Tip: useRef is used to persist values across renders without triggering re-renders and is commonly used for DOM access and storing mutable values. Follow Tarun Kumar for tech content, coding tips, and interview prep #React #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #CodingInterview #InterviewPreparation #SoftwareEngineering #TechLearning #Programming