Pranjal Rawat’s Post

🚀 Just wrapped up a React.js Interview — Key Takeaways! Today I had an interesting discussion in a React.js developer interview, and it reminded me how important strong fundamentals are — especially for frontend roles. Here are some key topics that came up 👇 🔹 JavaScript Fundamentals Closures and real-time use cases Event loop behavior (setTimeout + var vs let) Output-based questions like: JavaScript for (var i = 0; i < 3; i++) { setTimeout(() => console.log(i), 100); } 👉 Output: 3 3 3 (due to closure + function scope) 🔹 React Concepts Custom hooks (like useLocalStorage) Redux vs Context API Error handling in enterprise apps Latest React features (React 19 insights) 🔹 System Design & Architecture Microfrontend architecture Communication between multiple applications/plugins Data flow strategies in scalable systems 🔹 Frontend Tools & Practices Tailwind CSS setup & benefits Form handling (React Hook Form / Formik) TypeScript advantages in frontend & Node.js 💡 One thing I realized again: Strong understanding of core JavaScript + real-world implementation experience is what makes the difference in interviews. 🔥 Tip for fellow developers: Don’t just memorize concepts — understand why things behave the way they do. Let’s grow together 🚀 #ReactJS #FrontendDeveloper #JavaScript #ProductBasedCompanies #SystemDesign #Microfrontend #TypeScript #InterviewExperience #TechCareers

🚀 My Interview Experience with FanCode (Frontend Focus) Recently went through a multi-round interview process at FanCode. Thought of sharing the experience, especially for developers preparing for strong frontend roles. There was total 5 rounds. Pre-Assessment (HackerRank OA) This round was focused on core JavaScript depth, not surface-level knowledge. JavaScript circular dependency Polyfill for Promise.all Polyfill for setTimeout & clearTimeout If you can’t build JS internals, you don’t truly understand JS. 1. Round 1 (Core JavaScript Deep Dive) This was intense. Mostly focused on async behavior and fundamentals: What is a Promise Event Loop (Microtasks vs Macrotasks) Polyfill for fetch Fetch with caching Handling in-flight request caching Output-based questions Example: JavaScript console.log('A') setTimeout(()=> { console.log('B') },0) Promise.resolve(1).then(() => { console.log('C') }) async function run(){ console.log('D') await Promise.resolve(2) console.log('E') } run() console.log('F') 2. Round 2 (Machine Coding and React / React Native) Problem: Build N progress bars Only one runs at a time (sequential execution) Button to dynamically add progress bars Follow-up: Run progress bars in batches of 3 After completion, trigger next batch Discussion: Performance optimizations Avoid unnecessary re-renders Efficient state management Handling timers properly Cleanup & memory considerations This round tests how you think while building, not just code. Round 3 (System Design) Design a LinkedIn-like notification system Focus on scalability, real-time updates, and architecture. It was a quite long discussion around 1.5 hour about the system and different trade offs. (I couldn’t clear this round but learned a lot.) Key Learnings JavaScript fundamentals > frameworks Polyfills are underrated but powerful Async flow clarity is a must Machine coding = structured thinking under pressure System design is a different game altogether If you’re preparing for frontend roles: Don’t just “use” features. understand how they work internally. Happy to help anyone preparing for similar interviews. #Frontend #JavaScript #React #InterviewExperience #WebDevelopment #SystemDesign

Frontend interviews aren’t really about React… Here’s a round-wise breakdown with some of the most asked questions 👇 🔹 JavaScript (Most Important Round) This is where most candidates struggle. 1. What is closure? Where have you used it? 2. Explain event loop with execution order 3. Implement debounce/throttle in JavaScript 4. How does "this" behave in different contexts? 5. Promise chaining vs async/await 🔹 Round 2: React Deep Dive 1. Why do components re-render? 2. useMemo vs useCallback vs React.memo 3. How does useEffect lifecycle work? 4. How do you prevent unnecessary renders? 5. Real-world state management approach 🔹 Round 3: Machine Coding 1. Build a debounced search / autocomplete 2. Handle API calls with proper states 3. Focus on clean architecture & reusability 4. Edge cases + performance considerations 🔹 Round 4: Frontend System Design 1. Design a scalable UI (dashboard/feed) 2. Folder structure & code organization 3. API handling and caching 4. Performance optimization techniques 🔹 Round 5: Hiring Manager Round 1. Deep dive into your project 2. Why did you choose certain approaches 3. Challenges and trade-offs 4. Ownership and decision making 💡 Biggest takeaway: Frameworks change, but strong fundamentals stay. Don't forget to like this post and follow Revanth Sai 🚀 for more :) #Frontend #JavaScript #React #InterviewExperience #WebDevelopment #SDE

Frontend interviews are evolving… and honestly, I’ve started noticing it too.👀 Earlier, most discussions were around frameworks - React basics, hooks, lifecycle, etc. But now, the focus is clearly shifting towards something more practical: real-world performance. It’s no longer just about how you build - it’s about how fast and efficiently it runs for users. Questions like:👇 ()=> What impacts LCP or CLS? ()=> How do you improve loading performance? ()=> What’s actually blocking rendering? ()=> What should load first vs what can wait? These are becoming more common - and it makes sense. Because at the end of the day, users don’t care how clean your code is if the app feels slow. One thing I’ve realized while working on real projects is: 👇 ()=> Performance is not a separate task - it’s part of how you think while building. Things like: ()=> Reducing unnecessary renders ()=> Lazy loading where it actually matters ()=> Structuring components efficiently ()=> Optimizing API calls These decisions directly impact user experience. I’ve started paying more attention to: “What is the user seeing first?” “What can be optimized or deferred?” “What is slowing this down?” Still learning and improving in this area, but one thing is clear - Performance is no longer optional for frontend developers. Curious to know - are you also seeing this shift in interviews or projects?🤔 #frontend #reactjs #frontendInterviews

Most frontend developers fail interviews… not because they can’t code 😶 But because they don’t know the right concepts. I analyzed 30+ commonly asked frontend interview questions… and here’s what actually matters 👇 🔹 HTML (Basics but powerful) – Semantic tags (header, footer, article) – Difference between div and section – Importance of alt & meta tags 🔹 CSS (Where most people struggle) – Box Model (VERY IMPORTANT) – Positioning (relative vs absolute vs fixed) – Inline vs block vs inline-block – Media queries (responsiveness is a MUST) 🔹 JavaScript (Game changer) – var vs let vs const – Closures (an interview favorite) – DOM & event delegation – Arrow functions 🔹 Advanced JavaScript – Sync vs async – Promises + async/await – Hoisting – Higher-order functions 🔹 React / Frontend system design – Virtual DOM – One-way vs two-way binding – Hooks (useState, useEffect) – Component lifecycle 🔹 Performance optimization (🔥 underrated) – Lazy loading – CDN – Critical CSS – Handling large datasets 💡 Truth: You don’t need to know EVERYTHING. You need to understand the RIGHT things deeply. I’m currently preparing for full-stack (MERN) roles, focusing on frontend + backend concepts, and sharing what I learn along the way. If you're also preparing, let’s grow together 🚀 #mern #fullstack #javascript #reactjs #nodejs #webdevelopment #coding #developers #softwareengineer #jobsearch #interviewprep

Frontend interviews are no longer just about React. They’re about how deeply you understand JavaScript and the web. Here’s what modern frontend interviews actually cover 👇 🔹 JavaScript Core & Advanced • First-class functions • Execution context & call stack • Hoisting & Temporal Dead Zone (TDZ) • this (regular vs arrow functions) • Currying & pure vs impure functions • Debounce vs throttle • Shallow vs deep copy • undefined vs null, optional chaining, nullish coalescing • Garbage collection & memory management • Event loop, streams & backpressure • Performance pitfalls (e.g. object de-optimization) 🔹 Async & Architecture • Promises & async/await flow • Concurrency handling • Preventing starvation • Task scheduling & execution order 🔹 React & Frontend Fundamentals • JSX & reconciliation • Component lifecycle (actual phases) • Controlled vs uncontrolled components • Error boundaries • Event handling patterns • useEffect behavior & optimization 🔹 Next.js & Backend Awareness • Server-side handling • API methods (GET, POST, PUT, DELETE) • REST structure & optimization thinking 🔹 Problem Solving • Breaking problems step-by-step • Optimization thinking before coding • Handling edge cases 💡 The shift is clear: Frontend interviews are moving from “Can you build UI?” → “Do you understand systems?” If you’re preparing, don’t just focus on frameworks. Focus on how things work under the hood. Which area do you think is the hardest — JavaScript, React, or System Design? 👇 #Frontend #JavaScript #React #NextJS #CodingInterview #SoftwareEngineering

Frontend interviews are no longer just about React. They’re about how deeply you understand JavaScript and the web. Here’s what modern frontend interviews actually cover 👇 🔹 JavaScript Core & Advanced • First-class functions • Execution context & call stack • Hoisting & Temporal Dead Zone (TDZ) • this (regular vs arrow functions) • Currying & pure vs impure functions • Debounce vs throttle • Shallow vs deep copy • undefined vs null, optional chaining, nullish coalescing • Garbage collection & memory management • Event loop, streams & backpressure • Performance pitfalls (e.g. object de-optimization) 🔹 Async & Architecture • Promises & async/await flow • Concurrency handling • Preventing starvation • Task scheduling & execution order 🔹 React & Frontend Fundamentals • JSX & reconciliation • Component lifecycle (actual phases) • Controlled vs uncontrolled components • Error boundaries • Event handling patterns • useEffect behavior & optimization 🔹 Next.js & Backend Awareness • Server-side handling • API methods (GET, POST, PUT, DELETE) • REST structure & optimization thinking 🔹 Problem Solving • Breaking problems step-by-step • Optimization thinking before coding • Handling edge cases 💡 The shift is clear: Frontend interviews are moving from “Can you build UI?” → “Do you understand systems?” If you’re preparing, don’t just focus on frameworks. Focus on how things work under the hood. Which area do you think is the hardest — JavaScript, React, or System Design? 👇 #Frontend #JavaScript #React #NextJS #CodingInterview #SoftwareEngineering

🚀 “When you know the answer… but say it wrong under pressure 😅” Today’s React.js interview was a rollercoaster. 💻 Everything was going smooth — ✔ JavaScript concepts (event loop, closures) ✔ React topics (code splitting, lazy loading) ✔ Problem-solving discussions Then came the live coding + screen share round 👇 I had to build a small React app and explain what happens on state update — like mount, re-render, unmount. 👉 And that’s where things got funny (and real). I knew the concepts… but under pressure, I kept calling re-render as unmount 🤦♂️ For a few moments, even the interviewer smiled… and then I realized — I was just mixing terms, not lacking knowledge. 💡 That moment taught me something important: Interviews don’t just test what you know… they test how clearly you can express it under pressure. 👉 I corrected myself later, but yeah — that slip stayed with me. Still, I’m taking this as a win: ✔ I didn’t panic ✔ I stayed honest ✔ I learned exactly where I need improvement Now I’ll focus more on: ✔ Clear communication of concepts ✔ Practicing under real interview pressure Because growth comes from these exact moments. 🚀 --- Reference (for preparation): - Webpack Bundle Optimization - Handling pressure in live coding rounds --- #ReactJS #FrontendDeveloper #JavaScript #InterviewExperience #ReactDeveloper #CodingInterview #DevelopersLife #LearningJourney #Frontend #WebDevelopment #JobSearch #InterviewPrep #SoftwareEngineer #KeepLearning #CodeDaily #ReactInterview #JS #WebDev #CareerGrowth 😅

❌ Why Frontend Interviews Feel So Tough Everyone thinks frontend is “just UI”… but interviews tell a different story. 👉 You’re expected to know: • Deep JavaScript (closures, prototypes, async) • React internals (rendering, hooks, optimization) • System design (scalable frontend architecture) • Performance (lazy loading, memoization, caching) • Browser concepts (event loop, DOM, reflow/repaint) 👉 And that’s not all: • Write clean, scalable code • Handle edge cases on the spot • Explain decisions clearly Reality: Frontend is no longer about buttons and colors. It’s about building fast, scalable, production-grade systems. 💡 The difference between rejection and selection? Strong fundamentals + real project experience. If you're preparing: Stop just watching tutorials. Start building. Follow Hrithik Garg 🚀 for more :) #Frontend #WebDevelopment #JavaScript #ReactJS #InterviewPrep #SoftwareEngineering #CareerGrowth

🚀 Day 9/90 — Becoming a Job-Ready Frontend Engineer Today I went deeper into Advanced Array Methods in JavaScript — the kind of concepts that are used daily in React applications and frequently asked in interviews. Focused on: 🔹 sort() — and why it can be dangerous if you don’t use a compare function 🔹 find() — returning the first matching item 🔹 some() — checking if at least one condition passes 🔹 every() — verifying if all elements satisfy a condition One important realization: By default, sort() converts elements to strings before comparing — which can lead to unexpected results. Example: [10, 2, 5].sort() → ❌ Incorrect order Correct approach: array.sort((a, b) => a - b) Another key learning: Understanding the difference between: • find() → returns a single item • filter() → returns a new array • some() → returns boolean (stops early) • every() → returns boolean (stops early) These methods are essential for: ✔ Rendering filtered lists in React ✔ Handling API data ✔ Validating form conditions ✔ Writing clean, functional JavaScript The more I practice arrays, the more I realize frontend engineering is about thinking functionally and avoiding unnecessary mutations. Next: Deep dive into Objects — destructuring, spread operator & immutability. #FrontendDevelopment #JavaScript #WebDevelopment #ReactJS #NextJS #SoftwareEngineering #ProgrammingJourney #100DaysOfCode #RemoteDeveloper #TechCareer