JavaScript Concepts for Seamless User Experience

🪝: Our app was slow. Users were complaining. Here's the 5 things that fixed it (and the 1 thing that almost made it worse). Performance optimisation is one of those things that sounds abstract until you have actual users complaining. Here's what I've done in real projects that actually moved the needle: 1. CODE SPLITTING with React.lazy() → Don't load the whole app on first visit → Lazy load routes and heavy components → Real impact: cut initial load time by ~40% on a large project 2. MEMOISATION — but only where it matters → React.memo() for components that receive the same props often → useMemo() for expensive calculations → useCallback() for functions passed as props → WARNING: Over-memoising adds overhead. Profile first, optimise second. 3. OPTIMISED RENDER CYCLES → Identify what's causing unnecessary re-renders (React DevTools Profiler is your best friend) → Move state as close to where it's used as possible → Avoid storing derived data in state — calculate it 4. IMAGE OPTIMISATION → Lazy load images below the fold → Use appropriate formats (WebP where possible) → Set explicit width/height to avoid layout shifts 5. BUNDLE ANALYSIS → Use webpack-bundle-analyzer or Vite's rollup-plugin-visualizer → You'll be shocked what's in your bundle sometimes The thing that almost made it worse? Premature memoisation everywhere. We wrapped every component in React.memo before profiling. It actually slowed things down. MEASURE. THEN OPTIMISE. What's your go-to performance trick? #ReactJS #PerformanceOptimisation #FrontendDev #JavaScript #WebPerformance #CodeSplitting #ReactHooks

🚀 Day 24/30 – Error Boundaries (Handle Crashes Gracefully) Everything works fine… until ONE component crashes your entire app 💥 And suddenly 👇 👉 White screen 👉 Angry users 👉 Debugging nightmare 😵 Today I learned how real-world React apps handle this ⚡ 👉 Error Boundaries --- 💻 The Problem: In React, if a component crashes ❌ 👉 The whole app can crash --- 💻 The Solution: 👉 Error Boundaries = Safety Net 🛡️ They catch errors and show fallback UI instead of breaking everything. --- 💻 Example: class ErrorBoundary extends React.Component { constructor(props) { super(props); this.state = { hasError: false }; } static getDerivedStateFromError() { return { hasError: true }; } componentDidCatch(error, info) { console.log(error, info); } render() { if (this.state.hasError) { return <h2>Something went wrong 😢</h2>; } return this.props.children; } } --- 💻 Usage: <ErrorBoundary> <Dashboard /> </ErrorBoundary>--- 🔥 What actually happens: ❌ Without Error Boundary → Whole app crashes ✅ With Error Boundary → Only broken component fails → Rest of app works smoothly --- 💡 Why this matters: - Better user experience - Prevents full app crash - Essential for production apps --- ⚡ Advanced Insight (Most people don’t know): Error Boundaries do NOT catch: ❌ API errors ❌ setTimeout errors ❌ Event handler errors 👉 You still need proper error handling there --- 🔥 Key Takeaway: Good developers fix bugs… 👉 Great developers prevent crashes --- Be honest 👇 If your app crashes today… will users see a fallback UI or a blank screen? 👀 #React #ErrorHandling #FrontendDevelopment #JavaScript #CleanCode

I shipped an improved version of my Budget Sharing app after reflecting on feedback from my last post. Initially, the app was doing the calculations correctly but something felt off. The problem wasn’t the logic. It was the clarity. Users had to look through balances and mentally figure out who pays who. So I changed the focus of the app: Introduced a clear “Who pays who” section at the top Made settlement instructions immediately visible Kept currency formatting clean and consistent (.toFixed(2)) Now instead of: “Here’s the math” The app tells you: “Here’s exactly what to do” That shift made a bigger difference than any UI tweak. Still improving: Better visual hierarchy (making key info stand out more) Cleaner layout for totals vs actions This project is helping me understand that frontend isn’t just about building components it’s about reducing thinking for the user. Tech stack: React + Tailwind + LocalStorage Live demo: https://lnkd.in/dTzrDHgc Code: https://lnkd.in/drybpSAw Would appreciate any feedback hashtag#frontend hashtag#reactjs hashtag#webdevelopment hashtag#buildinpublic hashtag#portfolio

🚨 Your React app might be re-rendering 10x more than it should — and you don’t even know it. I learned this the hard way while building a shopping app. I had a child component inside a parent. Every time the parent’s state changed — even for something unrelated — the child re-rendered completely. The UI started feeling sluggish… and I couldn’t figure out why. Sound familiar? So what is a re-render? In React, a re-render means a component function runs again and updates the UI. Some re-renders are necessary. But unnecessary ones? They quietly kill performance. React doesn’t compare values — it compares references. That means even if two objects look the same, React treats them as different if they don’t share the same reference in memory. ⚠️ Common causes of unnecessary re-renders ❌ Passing new objects/arrays as props on every render ❌ Recreating functions inside components without memoisation ❌ Storing values in state that don’t affect UI ❌ Component identity changing between renders 🛠️ What actually fixed it for me 1. Stabilise component structure If a component’s identity changes between renders, React treats it as new and remounts it. Keep component definitions stable. 2. Use React.memo (when it matters) It prevents re-renders only if props haven’t changed. Not magic—but very useful. 3. Memoise functions and values useCallback for functions useMemo for computed values Especially when passing them as props. 4. Be intentional with state Every state update triggers a re-render. If it doesn’t affect UI → it probably shouldn’t be state. 💡 The shift Re-rendering isn’t the problem. Uncontrolled re-rendering is. Once I understood this, debugging became way easier—and my app got noticeably faster. If you’re building with React right now, take a second look at your components. You might find a silent performance bug hiding in plain sight 👀 💬 What’s the trickiest React bug you’ve run into? #React #Frontend #WebDevelopment #JavaScript #ReactDeveloper #Programming #100DaysOfCode

Your React app feels slow, and you have no idea why. The truth is, it is probably re-rendering 10x more than it should be. React core philosophy is that UI is a function of state. When state changes, React re-evaluates the component tree. But if you are not careful, a single state change at the top of your tree can trigger a massive wave of unnecessary re-renders all the way down to the bottom. Here are the 3 most common reasons your React app is re-rendering too much: 1. Passing new object references in props. If you pass an inline object or function like style={{ color: 'red' }} or onClick={() => doSomething()}, React sees a brand new reference on every single render. Even if the contents are identical, React thinks the prop changed. 2. State lifted too high. If you have a form input that updates on every keystroke, and its state lives in a parent component alongside heavy data tables, typing one letter re-renders the entire table. 3. Missing memoization. Complex calculations or heavy child components that do not depend on the changed state will still re-render by default. React is fast, but it is not magic. Example: Instead of passing inline functions like this: <Button onClick={() => handleSubmit()} /> Use useCallback to keep the reference stable: const handleSubmit = useCallback(() => { ... }, []); <Button onClick={handleSubmit} /> Key takeaways: - Keep state as close to where it is used as possible. - Use memo for expensive child components. - Use useMemo and useCallback to preserve reference equality for objects and functions passed as props. #reactjs #webdevelopment #frontend #javascript #performance #softwareengineering #coding #webdev #reactdeveloper #programming

🚀 𝗗𝗲𝗰𝗼𝗱𝗲 𝗠𝗘𝗥𝗡 𝘄𝗶𝘁𝗵 𝗠𝗲 – 𝗗𝗮𝘆 𝟳 Today’s focus wasn’t just UI… It was about writing smarter React code. I explored 𝗖𝘂𝘀𝘁𝗼𝗺 𝗛𝗼𝗼𝗸𝘀— a concept that changes how you structure your applications. Instead of repeating logic in multiple components, I learned how to extract it into a reusable function. So I built a simple project to apply it 👇 📌 𝗣𝗿𝗼𝗷𝗲𝗰𝘁: Notes App with Auto Save A minimal app, but with a strong concept behind it. ✔ Notes are saved automatically ✔ Data persists even after refresh ✔ No backend used — everything handled in the browser ✔ Clean and simple UI with Tailwind CSS ⚙️ 𝗪𝗵𝗮𝘁 𝗺𝗮𝗱𝗲 𝗶𝘁 𝗶𝗻𝘁𝗲𝗿𝗲𝘀𝘁𝗶𝗻𝗴? I created a custom hook: useLocalStorage This hook handles: • State management • Data storage • Sync between UI and localStorage One hook → reusable logic → cleaner components 🧠 𝗞𝗲𝘆 𝗧𝗮𝗸𝗲𝗮𝘄𝗮𝘆: When your logic is reusable, your code becomes scalable. And that’s where React starts to feel powerful. 🔗 𝗖𝗼𝗱𝗲: https://lnkd.in/gBuMk4TG Learning one concept at a time. Building one project at a time. #MERN #ReactJS #CustomHooks #WebDevelopment #LearningInPublic #100DaysOfCode

🚀React Bundle Analysis & Optimization Your React app might look fine… But if your bundle is heavy, users will feel the slowdown ⚠️ Let’s break this down simply 👇 🧩 What is a Bundle? 👉 When you build a React app, all your code + libraries are combined into JavaScript files (bundles) 💡 Example: • React • UI libraries • Utility functions ➡️ All packed into one or multiple JS files ⚠️ Why Large Bundles Are a Problem ❌ Slow initial load ❌ More JavaScript to execute ❌ Poor performance on low-end devices 👉 Bigger bundle = Slower app 🔍 What is Bundle Analysis? 👉 It helps you understand: • Which library is heavy • What is increasing bundle size • Where optimization is needed 📊 Tools give a visual breakdown of your bundle 🛠️ Tools You Can Use ✔ webpack-bundle-analyzer ✔ source-map-explorer 👉 Shows which dependency is taking the most space ⚡ How to Optimize Bundle 🧩 1. Code Splitting → Break bundle into smaller chunks ⚡ 2. Lazy Loading → Load components only when needed 🌳 3. Tree Shaking → Remove unused code automatically 📦 4. Dynamic Imports → Load heavy modules on demand 🧹 5. Remove Heavy Libraries → Replace with lighter alternatives 🔥 Real Impact ✔ Faster load time ✔ Better performance ✔ Improved user experience ✔ Smaller bundle size 🧠 Simple Way to Understand • Without Optimization → Big bundle → Slow app ❌ • With Optimization → Small chunks → Fast app ✅ 💬 Have you ever checked what’s inside your bundle? #React #WebPerformance #Frontend #JavaScript #WebDevelopment #Optimization #Coding #SoftwareEngineering

I got tired of rewriting the same scroll logic… so I built a reusable React hook 👇 In one of my projects, I had multiple places where I needed: → Detect when a user is near the bottom → Trigger API calls (pagination / infinite scroll) → Handle different containers (not just window scroll) Initially, I was repeating this logic everywhere. So I extracted it into a custom hook: 👉 useTableScrollPagination What it does: • Works with both containers and tables (AG Grid in my case) • Lets me control when to trigger (75%, 90%, etc.) • Prevents duplicate API calls while loading • Keeps scroll position intact after data updates The biggest win? 👉 I no longer think about scroll logic — I just reuse it. I know there are libraries for infinite scroll, but in real-world apps: → Custom containers → Complex UI structures → Different trigger behaviors …often need a more flexible approach. Curious — how are you handling infinite scroll in your apps? Library or custom solution? #ReactJS #FrontendDevelopment #TypeScript #DeveloperExperience

Built a simple yet powerful **To-Do List Web App** from scratch 🗒️ Focused on making it not just functional, but also intuitive and visually clean. From handling dynamic DOM manipulation to managing state with localStorage, this project helped me understand how real-world apps maintain consistency even after refresh. ✨ Key Features: • Data persists even after page reload using localStorage as you can see in the demo video. * Add & delete tasks dynamically * Checkbox-based task completion * Persistent data using localStorage * Clean UI with color variations * Real-time updates without reload One interesting challenge was syncing checkbox state with stored data — learned a lot about how DOM properties and HTML attributes behave differently under the hood. Projects like this may look simple, but they build the foundation for scalable applications and better frontend thinking. Excited to keep improving and adding more features 🔥 #webdevelopment #frontenddeveloper #javascript #coding #programming #100daysofcode #buildinpublic #learningbydoing #studentdeveloper #btech #devjourney #softwaredevelopment #uiux #localstorage #dommanipulation #beginnersproject #tech #innovation #productivity #webdev #githubprojects #codinglife #engineer #learning #growth #career

Improving logic in web apps, one small build at a time 👇 Instead of jumping straight into big projects, I’m going through a playlist of 30 micro projects — but with a twist: not just building them, but understanding how to make them scalable, clean, and future-proof. Day 1: Digital Clock ⏰ (built in 3 different ways) Same output, different approaches — and that’s where the real learning happens. The goal isn’t just to “complete projects” It’s to train thinking like a developer who can design systems. I’ll be sharing everything I build here: 🔗 GitHub: https://lnkd.in/dVdN4rsW⁠� 📸 Daily updates: https://lnkd.in/dGfyveGh⁠� Let’s see where 30 days of consistency leads 🚀 #WebDevelopment #BuildInPublic #LearningInPublic #JavaScript #FrontendDevelopment #DeveloperJourney #CodingLife #100DaysOfCode