React Elements vs Components: Understanding the Basics

🔥 Frontend Interview Questions You MUST Know 1️⃣ What are the component lifecycle methods in class components and how are they handled in functional components? 2️⃣ Walk me through controlled vs uncontrolled components in React. 3️⃣ Can you explain event delegation in JavaScript with an example? 4️⃣ What are closures in JavaScript? What are their advantages and disadvantages? 5️⃣ How do memory leaks happen in frontend applications? How can you prevent them? 6️⃣ What is garbage collection in JavaScript? Can you explain the Mark and Sweep algorithm? Comment your answers below or save this post to revise later before your next interview! Let’s learn together 🚀 #FrontendDeveloper #JavaScript #ReactJS #InterviewPreparation #FrontendInterview #WebDevelopment #Frontend #ReactDeveloper

In almost every React interview I’ve attended, one question always shows up… “Explain React lifecycle methods.” React components go through three phases: → Mounting (component is created and inserted into the DOM) Important methods: • constructor() → initialize state • render() → returns the UI • componentDidMount() → best place for API calls or data fetching → Updating (when props or state change) Important methods: • shouldComponentUpdate() → control re-renders for performance • render() → updates the UI • componentDidUpdate() → run logic after updates → Unmounting (component is removed from the DOM) Important method: • componentWillUnmount() → cleanup tasks like removing event listeners or cancelling timers Understanding lifecycle methods tells interviewers one important thing: You don’t just use React… You understand how it behaves behind the scenes. #React #FrontendDevelopment #JavaScript #TechInterviews #WebDevelopment

Frontend Interview Experience – A Small but Interesting Redux Debate Recently attended a frontend interview where the discussion covered HTML, CSS, JavaScript, React, GraphQL, and Microfrontends. During the React round, I was asked about the core pillars of Redux. I explained: • Store – holds the application state • Actions – plain JavaScript objects describing what happened • Reducers – pure functions that return the new state • Dispatch – sends actions to the store • Selectors – used to read data from the store Then came an interesting moment The interviewer mentioned that "Actions are functions, not objects." I respectfully shared my understanding that: In Redux, an Action is a plain JavaScript object with a mandatory type field. After the interview, I double-checked — and yes, Redux defines actions as plain objects. The likely confusion: What the interviewer referred to was Action Creators, which are functions that return action objects. Example: const addTodo = (text) => ({ type: "ADD_TODO", payload: text }); Key takeaway: • Action = Object • Action Creator = Function 🎯 Interviews are not just about right or wrong — they’re about clarity of concepts and communication. Curious to know — have you ever faced a situation where both perspectives were technically correct but misunderstood in interviews? #Frontend #React #Redux #JavaScript #InterviewExperience #Learning

❓ React Interview Question: What is useEffect? ✅ Answer: useEffect is a React Hook used to handle side effects in functional components. Side effects include operations like API calls, subscriptions, timers, and DOM updates. It runs after the component renders and can be controlled using a dependency array to decide when it should execute. 💡 Why we use useEffect? React components are meant to be pure, but real-world applications need to: --> fetch data from APIs --> set up event listeners --> work with timers useEffect allows us to perform these operations safely after rendering. #ReactJS #FrontendDevelopment #WebDevelopment #JavaScript #SoftwareEngineering #InterviewPreparation #CodingInterview

💡 Frontend Interview Questions I Found Interesting While preparing for frontend interviews, I came across some questions that really test your understanding beyond basics: JavaScript: 1️⃣ What is the output and why? console.log([] == ![]); 2️⃣ Explain how the event loop works in JavaScript. 3️⃣ What’s the difference between == and ===? When can == be tricky? 4️⃣ How do closures work in real-world scenarios? React: 5️⃣ What causes unnecessary re-renders in React? How do you optimize them? 6️⃣ Difference between useEffect and useLayoutEffect? 7️⃣ How does React’s reconciliation algorithm work? 8️⃣ How would you design state management for a large-scale application? 💭 These questions made me realize: Knowing syntax is not enough — understanding behavior and thinking deeply is what matters in interviews. Still learning and improving every day 🚀 #javascript #reactjs #frontenddevelopment #interviewprep #webdevelopment

🚀 React Interview Question Breakdown – Can You Spot the Issues? Recently, I came across some interesting React interview questions focused on debugging and code optimization. Sharing them here 👇 🔍 Question 1: Find the issues and fix them const items = useSelector(state => state.items); const [filtered, setFiltered] = useState(items); useEffect(() => { setFiltered(items.filter(i => i.name.includes(search))); }, []); 🔍 Question 2: Find the issues and fix them const handleLike = async () => { const newCount = likes + 1; setLikes(newCount); await api.updateLikes(newCount); if (condition) { setLikes(likes + 1); // Review point } }; #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #InterviewQuestions #ReactHooks

🚀 Day 8 of Frontend Developer Interview Preparation Today I dived deeper into how JavaScript actually works behind the scenes ⚙️ 📌 Topics I learned: Event Loop Microtask Queue Callback Queue JavaScript Engine Understanding these concepts changed the way I look at async code. Now I know: 👉 JavaScript doesn’t “wait” — it manages everything using queues and the event loop 👉 Promises (microtasks) always execute before setTimeout (callback queue) 👉 The JS engine executes code using the call stack while Web APIs handle async tasks This is one of those topics that looks simple, but the deeper you go, the more interesting it becomes 🔥 Next step: I’ll practice tricky output-based questions on these concepts to strengthen my understanding 💪 If you’re preparing for frontend interviews, make sure you understand this topic well — it’s a game changer 🚀 #Day8 #FrontendDeveloper #JavaScript #EventLoop #WebDevelopment #InterviewPreparation

🚀 3 Tricky React Interview Questions Asked in Top Companies These are NOT your typical “what is useState?” questions. These are the ones that actually test your real understanding of React 👇 ⸻ 1️⃣ Why does a component re-render even with React.memo? You wrapped a child with React.memo. Props look the same… but it still re-renders. 👉 Reason: React.memo does shallow comparison 👉 Objects, arrays, and functions create new references every render 💡 Fix: Use useMemo / useCallback to stabilize references ⸻ 2️⃣ Why is useEffect running twice in development? You used an empty dependency array, still it runs twice 🤯 👉 This is NOT a bug 👉 It’s React Strict Mode (React 18+) 💡 React intentionally mounts → unmounts → mounts again to detect side effects & bugs early ✅ Happens only in development, not in production ⸻ 3️⃣ Why is state not updating inside async functions? You update state, but inside setTimeout or async code it still shows the old value 😵 👉 Reason: Stale closures (JavaScript behavior) 💡 Fix: ✔️ Use functional updates → setState(prev => prev + 1) ✔️ Or useRef for latest value ⸻ 🎯 Interview Tip: Use these keywords to stand out: ✔️ Shallow comparison ✔️ Reference equality ✔️ Strict Mode behavior ✔️ Stale closures #ReactJS #FrontendDeveloper #WebDevelopment #JavaScript #InterviewPrep #ReactInterview #Coding #interview #prepration #Developer

💼 Top 5 Frontend Interview Questions I Got Here are some questions I recently came across as a Frontend Developer 👇 1️⃣ What is the difference between == and === in JavaScript? 2️⃣ How does Angular change detection work? 3️⃣ What is trackBy in ngFor and why is it important? 4️⃣ Difference between Promises and Observables? 5️⃣ How do you improve performance in a frontend application? These questions made me realize how important fundamentals are 👀 Still learning and improving every day 🚀 What’s a question you’ve been asked in interviews? #FrontendDeveloper #Angular #JavaScript #InterviewPrep #WebDevelopment

🚀 Day 13 of My Frontend Developer Interview Preparation Today I focused on understanding the “this” keyword in JavaScript along with revising some core basics. 🔹 Learned how this behaves differently based on context: In global scope Inside objects Inside regular functions vs arrow functions In event handlers 🔹 Understood that this is not fixed — it depends on how a function is called, which makes it a very important (and sometimes tricky) concept in interviews. 🔹 Also revised key JavaScript fundamentals: Arrays & Objects Shallow vs Deep Copy Destructuring Spread & Rest Operators 💡 The more I learn, the more I realize that strong fundamentals are the real game changer for cracking interviews. Tomorrow’s plan: Practice tricky questions on these topics and strengthen my problem-solving 🚀 #JavaScript #FrontendDevelopment #WebDevelopment #CodingJourney #InterviewPreparation #LearningEveryday