React Frontend Concepts Checklist and Interview Prep

Important Frontend Concepts Checklist- 1. Pagination 2. Infinite Scrollbar 3. Debouncing 4. Websocket 5. REST vs GraphQl APIs 6. Local Storage vs Cookies 7. Authentication vs Authorization 8. Redux 9. Lazy Loading 10. Code Splitting 11. Bundle Size Optimization 12. Tree Shaking 13. Memoization (useMemo, useCallback) 14. Caching (Client + Server) 15. CSR vs SSR vs SSG vs ISR 16. Core Web Vitals (LCP, INP, CLS) 17. Cross Browser Compatibility 18. Optimistic UI Updates 19. Suspense (React) 20. Image Optimization (WebP, AVIF) 21. Accessibility (a11y) 22. Webpack 23. Micro-frontend Architecture 24. Testing- RTL, Jest, Playwright 25. Polyfills, Babel Get ebook with (detailed 232 ques = 50+ Reactjs Frequent Ques & Answers, 45+ Reactjs scenario based questions, 90+ frequently asked interview questions and answers, 50+ Output based ques & ans, 25+ Coding Questions & ans) 𝐄𝐛𝐨𝐨𝐤 𝐋𝐢𝐧𝐤: https://lnkd.in/gJMmH-PF Interview Guidance: https://lnkd.in/gr9PCuxd Follow on Instagram : https://lnkd.in/g-iSTsRd #javascript #javascriptdeveloper #reactjs #reactnative #vuejsdeveloper #angular #angulardeveloper

Important Frontend Concepts Checklist- 1. Pagination 2. Infinite Scrollbar 3. Debouncing 4. Websocket 5. REST vs GraphQl APIs 6. Local Storage vs Cookies 7. Authentication vs Authorization 8. Redux 9. Lazy Loading 10. Code Splitting 11. Bundle Size Optimization 12. Tree Shaking 13. Memoization (useMemo, useCallback) 14. Caching (Client + Server) 15. CSR vs SSR vs SSG vs ISR 16. Core Web Vitals (LCP, INP, CLS) 17. Cross Browser Compatibility 18. Optimistic UI Updates 19. Suspense (React) 20. Image Optimization (WebP, AVIF) 21. Accessibility (a11y) 22. Webpack 23. Micro-frontend Architecture 24. Testing- RTL, Jest, Playwright 25. Polyfills, Babel Get ebook with (detailed 232 ques = 50+ Reactjs Frequent Ques & Answers, 45+ Reactjs scenario based questions, 90+ frequently asked interview questions and answers, 50+ Output based ques & ans, 25+ Coding Questions & ans) 𝐄𝐛𝐨𝐨𝐤 𝐋𝐢𝐧𝐤: https://lnkd.in/gJMmH-PF Interview Guidance: https://lnkd.in/gr9PCuxd Follow on Instagram : https://lnkd.in/g-iSTsRd #javascript #javascriptdeveloper #reactjs #reactnative #vuejsdeveloper #angular #angulardeveloper

We often hear that JavaScript is single threaded. But at the same time, it handles API calls, timers, and UI updates smoothly. The reason is the Event Loop. Here is a simple way to understand it. Think in terms of 5 parts: 1. Call Stack This is where code runs right now. If something blocks here (like an infinite loop), everything else stops. 2. Web APIs The browser handles things like fetch, setTimeout, and events outside the main thread. When they are done, they send callbacks to queues. 3. Microtask Queue (high priority) This includes Promise callbacks and async/await. All microtasks run completely before anything else happens. -> If you keep adding microtasks (like recursive Promise.then), you can actually block rendering completely. 4. Macrotask Queue (low priority) This includes setTimeout, setInterval, and other tasks. Only one macrotask runs at a time. 5. Render After microtasks are done, the browser updates the UI (layout and paint). -> The browser decides when to paint — not strictly after every loop. Simple cycle: Run one macrotask → run all microtasks → update UI → repeat JavaScript isn’t non-blocking — the event loop just makes it feel that way. #javascript #frontend #reactjs #webdevelopment #softwareengineering #webperformance #systemdesign #Coding

Important Frontend Concepts Checklist- 1. Pagination 2. Infinite Scrollbar 3. Debouncing 4. Websocket 5. REST vs GraphQI APIs 6. Local Storage vs Cookies 7. Authentication vs Authorization 8. Redux ( Or any other state management library) 9. Lazy Loading 10. Code Splitting 11. Bundle Size Optimization 12. Tree Shaking 13. Memoization (useMemo, useCallback) 14. Caching (Client + Server) 15. CSR vs SSR vs SSG vs ISR 16. Core Web Vitals (LCP, INP, CLS) 17. Cross Browser Compatibility 18. Optimistic UI Updates 19. Suspense (React) 20. Image Optimization (WebP, AVIF) 21. Accessibility (a11y) 22. Webpack 23. Micro-Frontend Architecture 24. Unit Testing 25. Polyfills, Babel #ReactDeveloper #FrontEnd #FrontEndDeveloper #Javascript #Angular #AngularDeveloper #react #Typescript

The React pattern that has saved me the most time: custom hooks for shared logic. Not parts. Hooks. This is what kept happening to me: Several parts needed the same logic, like getting data, keeping track of the window size, and managing form state. I was copying and pasting useEffect and useState blocks all over the place. The solution is to put the logic into a custom hook. function useWindowWidth() { const [width, setWidth] = useState(window.innerWidth); useEffect(() => { const handler = () => setWidth(window.innerWidth); window.addEventListener('resize', handler); return () => window.removeEventListener('resize', handler); }, []); return width; } Now any component that needs the window width just calls: const width = useWindowWidth(); All of the cleanup logic, the event listener, and the state are taken care of in one place. What gets different: - Bugs are fixed once, not in five places. - Components are easier to read and understand. - It's easier and more isolated to test the logic. React becomes truly compositional when you utilize custom hooks. What is a custom hook you've made that you use all the time? #React #FrontendDeveloper #JavaScript #WebDev #ReactHooks

Important Frontend Concepts Checklist- 1. Pagination 2. Infinite Scrollbar 3. Debouncing 4. Websocket 5. REST vs GraphQl APIs 6. Local Storage vs Cookies 7. Authentication vs Authorization 8. Redux 9. Lazy Loading 10. Code Splitting 11. Bundle Size Optimization 12. Tree Shaking 13. Memoization (useMemo, useCallback) 14. Caching (Client + Server) 15. CSR vs SSR vs SSG vs ISR 16. Core Web Vitals (LCP, INP, CLS) 17. Cross Browser Compatibility 18. Optimistic UI Updates 19. Suspense (React) 20. Image Optimization (WebP, AVIF) 21. Accessibility (a11y) 22. Webpack 23. Micro-frontend Architecture 24. Testing- RTL, Jest, Playwright 25. Polyfills, Babel #javascript #javascriptdeveloper #reactjs #reactnative #vuejsdeveloper #angular #angulardeveloper

𝟵𝟵% 𝗼𝗳 𝗙𝗿𝗼𝗻𝘁𝗲𝗻𝗱 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿𝘀 𝘀𝘁𝗿𝘂𝗴𝗴𝗹𝗲 𝘄𝗶𝘁𝗵 𝘁𝗵𝗲𝘀𝗲 𝗳𝘂𝗻𝗱𝗮𝗺𝗲𝗻𝘁𝗮𝗹𝘀 👇 Not because they’re hard… But because we rarely revisit the “why” behind the tools we use daily. 1️⃣ Before Flexbox & Grid — how were responsive layouts actually built in CSS? 2️⃣ 𝗦𝗖𝗦𝗦 vs 𝗣𝗼𝘀𝘁𝗖𝗦𝗦 — what’s the real difference? And is SCSS still relevant in 𝟮𝟬𝟮𝟲? 3️⃣ Can you explain the 𝟳-𝗶𝗻-𝟭 SCSS architecture? What exactly are partials? 4️⃣ What does an async function return in JavaScript? Write the exact syntax. 5️⃣ Which asset formats are most optimal for modern HTML rendering (especially with srcset)? 6️⃣ What is a 𝗖𝗗𝗡 — and why are 𝗖𝗗𝗡 links usually placed inside <𝗵𝗲𝗮𝗱>. What breaks if you move them to <𝗯𝗼𝗱𝘆>? 7️⃣ Which CSS unit scales most effectively across different viewport sizes—and why? If you can confidently answer all of these, you’re already ahead of most developers in real-world frontend engineering. Curious — how many can you answer without Internet? 👀 ~ Aslam Mohammed #frontend #javascript #webdevelopment #css #reactjs #frontenddeveloper #webperf #programming #softwareengineering #devcommunity #100DaysOfCode #techcareers

Excited to share my latest project: a modern, responsive calculator built using HTML, CSS, and JavaScript! It’s fully functional, works on desktop and mobile, and is styled with a clean, modern UI. Check it out live here: https://lnkd.in/dGgZC_nx⁠� 💡 I’d love to hear your thoughts or suggestions! #WebDevelopment #Frontend #JavaScript #HTML #CSS #ResponsiveDesign #UI #UXDesign #Coding #Programming #Portfolio #WebDesign #Developer #TechProjects #SoftwareDevelopment #WebApp #CleanCode #ProjectShowcase #CodeNewbie #LearnToCode #100DaysOfCode

My list UI was behaving weirdly… items were changing unexpectedly 😅 Yes, seriously. At first, I thought it was a state issue. But the problem was something very simple. 💡 I was doing this: {items.map((item, index) => ( Seemed fine… right? ❌ ⚠️ This caused: • Wrong UI updates • Items swapping incorrectly • Hard-to-debug bugs 💡 Then I fixed it: 👉 Used a unique and stable key 🧠 Example: {items.map((item) => ( ✅ Result: • Correct UI updates • No unexpected behavior • Predictable rendering 🔥 What I learned: Keys are not just for React warnings 👉 they control how React updates the UI 💬 Curious: Do you still use index as key… or avoid it? #ReactJS #FrontendDeveloper #JavaScript #CodingTips #WebDevelopment