Don't Overuse useCallback for Performance Optimization

🔍 Your React app feels slow… where do you even start? Here’s the exact process I follow 👇 🧪 Step 1 — React DevTools Profiler Open it → hit record → reproduce the slow interaction Look for: • Long bars • Unexpected grey “did not render” gaps • Commits taking >16ms 🎨 Step 2 — "Highlight updates" toggle Turn it on. Now every re-render flashes on screen ✨ 👉 If your whole UI lights up when typing one character …you’ve found a problem. 🧰 Step 3 — why-did-you-render Install it: npm install @welldone-software/why-did-you-render It logs unnecessary re-renders + the reason behind them. Think of it as: 🧠 console.log for performance bugs 📊 Step 4 — Chrome DevTools Performance tab Use it for deeper analysis: • Paint • Layout • Scripting Look for: 🚨 Long tasks (red triangles) ⚠️ The order matters: Don’t jump to useMemo before running the Profiler. You’ll end up optimizing the wrong thing. 🧠 Better approach: Find the problem → Understand the cause → Fix it specifically #ReactJS #Performance #FrontendDevelopment #Debugging

I used to think I understood React… until I had to pass the same state through 3–4 components just to control one small thing 😅 It worked, but it didn’t feel right. So instead of jumping to another tutorial, I tried to actually "understand the problem" and that led me to the Context API. To keep things simple, I built a tiny “bulb toggle” app 💡 At first, everything was prop-based. Then I switched to Context… and the difference was obvious. Now: 1. I’m not passing props through unnecessary layers 2. Components feel more independent 3. The code is easier to read and reason about But I also learned something important while doing this: 👉 Context is helpful, but it’s not a replacement for everything If the state is simple and only needed in a few places, props are still totally fine. Context starts to make sense when multiple parts of your app need the same data. Still early in my journey, but this was one of those small moments where things started to click. If you’ve worked with Context before -> 👉 how do you decide between props, Context, or other state tools? #learninginpublic #reactjs #webdevelopment #javascript #frontenddevelopment

For a long time, I thought sprinkling useMemo and useCallback everywhere made my React apps faster. It didn't. It made them slower to read, harder to maintain, and in some cases measurably slower to run. What finally clicked: React.memo, useCallback, and useMemo aren't "optimization hooks." They're reference-equality tools. React.memo skips a re-render only if prop references are stable. If the parent passes a new object or arrow function each render, memo does nothing — except add comparison cost. useCallback and useMemo preserve reference identity. That matters only when a downstream consumer (a memoized child, a useEffect dep, a custom hook) is actually watching that reference. Without a consumer that cares, they're dead weight. But in the right places, these hooks are non-negotiable: → A table with 500 rows doing non-trivial work per row? React.memo is the difference between 60fps and visible jank. → A Context provider whose value is an object literal? Without useMemo, every consumer re-renders on every parent render. That one line can tank a whole app. → A function inside a useEffect dependency array? Without useCallback, you've written an infinite loop. → A custom hook returning a function for consumers to depend on? useCallback is how you don't silently break every caller. The rule I use now: Memoize when I can point to a specific thing that benefits. Otherwise, let React do its job. These hooks aren't reflexes. They're precision tools. Misuse them and you pay for machinery that does nothing. Place them right and the wins are massive — the kind that separate a smooth app from a laggy one. Learn them properly. They're worth it. #ReactJS #JavaScript #SoftwareEngineering

🧠 Why key Can Reset Your Entire Component State Most people think key is just for lists. It’s not. 👉 It can force React to destroy and recreate a component. 🔍 Example function App() { const [id, setId] = useState(1); return ( <> <button onClick={() => setId(id + 1)}>Next</button> <Profile key={id} /> </> ); } What happens? Every time id changes: 👉 React sees a new key 👉 It unmounts old component 👉 It creates a new one 💥 Result Inside Profile: const [count, setCount] = useState(0); 👉 count resets to 0 every time 🧠 Why? Because React thinks: “This is a completely new component” 🎯 Real use case You can use this intentionally: Reset form state Restart animations Clear component data 💥 Hidden danger Using unstable keys (like Math.random() or index) 👉 Can cause unexpected resets 👉 Leads to weird bugs 🧠 Final Insight key doesn’t just help React track elements It controls component identity #ReactJS #FrontendDevelopment #JavaScript #ReactTips #WebDevelopment #CleanCode #LearningInPublic

Today everything started to feel… more real. React Masterclass (Day 5). I began with: • Sharing state between components • Passing functions as props • Understanding how React handles state updates But instead of stopping there, I asked: How would this actually work in a real app? 💰 So I built a Budget Tracker: • Set initial balance • Add expenses that reduce it in real-time • Dynamic UI based on current state • Data persisted using localStorage • Clean updates using functional state 💡 Key concepts that clicked: • Lazy initialization (run logic only once) • Functional updates (state based on previous state) • Derived values (calculating remaining balance) Small concepts → Real product thinking. #React #Frontend #WebDevelopment #LearningInPublic #JavaScript

Ever wondered what actually happens inside React when your app updates? React does not directly change the browser UI every time something updates. Instead, it creates a Virtual DOM, which is a lightweight copy of the real DOM. When data changes, React builds a new Virtual DOM and compares it with the previous version. This process is known as reconciliation. • React checks what has changed between two versions • It updates only those specific parts in the real DOM • This makes updates faster and avoids unnecessary reloading React also follows a component-based structure. Each component manages its own state and logic, making the code easier to understand, reuse, and maintain. When state or props change, React decides when and how to re-render efficiently. This is why React applications stay fast even when they become large and complex. For more details, go to the link and see the full post: https://lnkd.in/eU-YtJw7 #React #ReactJS #JavaScript #FrontendDevelopment #WebDevelopment #Programming #SoftwareEngineering #MERNStack

Your React app is slower than it needs to be. Here's how to fix it. Most devs write React the way they learned it — and never revisit it. The result? Unnecessary re-renders, bloated bundles and lists that freeze on scroll. In this carousel I cover 5 patterns I apply to every React project: → useCallback & useMemo — when to use them (and when not to) → Why state lifting is silently killing your render tree → Code splitting: route-level is the highest ROI change you can make → Virtualisation for long lists — 10,000 rows in under 5ms → The performance checklist, in priority order Save this. Your users will notice the difference. If you found this useful, follow me for weekly React & full-stack tips. What's your go-to React performance trick? Drop it in the comments #ReactJS #ReactPerformance #FrontendDevelopment #WebDevelopment #JavaScript #TypeScript #SoftwareEngineering #Programming #WebPerformance #ReactNative #TechTips #FullStackDeveloper #CodeQuality #DeveloperTips #Frontend

🚀 Just launched: react-state-vitals A zero-config memory & render monitor for React apps. While working on production apps, I kept asking: 👉 Why is this component re-rendering so much? 👉 Which store is growing in memory? 👉 Where is my performance actually going? So I built a tool to make this visible — instantly. 🧠 react-state-vitals gives you a live floating panel in development: • 📊 Store size tracking (Zustand, Context, React Query) • 🔁 Re-render counts per component • 🧬 JS heap usage insights • ⚡ Zero setup — just install and see Think of it as: 👉 “Vitals for your React state & memory” 📦 Try it here: https://lnkd.in/gU692hyT 🔥 Next I’m planning: • DevTools-like overlay • Identify memory-heavy components in real time • Visual performance timeline Would love feedback from fellow devs 🙌 What would you want this to track next? #React #JavaScript #Frontend #WebPerformance #OpenSource #NextJS #Zustand

I noticed something small… that actually breaks user experience. Open the same app in two tabs. Change the language in one tab. The other tab stays the same. Now the user sees two different languages at the same time. That’s confusing. This happened in my React app. The feature worked perfectly… but only in a single tab. The problem wasn’t the backend. It was that tabs don’t share state by default. So I fixed it using the BroadcastChannel API. It lets tabs communicate with each other in real time. Now the flow is simple. • Change language in one tab • Send a message using BroadcastChannel • All other tabs receive it instantly • UI updates everywhere No refresh. No extra API calls. Everything stays in sync. For more advanced setups, this can also be combined with: • localStorage (for better browser support) • Service Workers (for more control) Final thought. Sometimes the issue isn’t the feature… It’s how it behaves in real-world usage. Would love to hear how others are solving multi-tab state problems. #React #JavaScript #Frontend #WebDevelopment #SoftwareEngineering #WebDev #FrontendDevelopment #Programming #Developers #Coding #BuildInPublic #DevCommunity #Tech #SoftwareDeveloper #ReactJS #JS #WebApps

Most developers try to optimize React apps… without knowing what’s actually slow. That’s the problem. Before you optimize… You need to measure. That’s where the React Profiler comes in 🔍 ⚡ What is React Profiler? A tool (inside React DevTools) that shows: • Which components are re-rendering • How long each render takes • Why a component re-rendered 🧠 What it helps you discover • Unnecessary re-renders • Slow components • Expensive computations • Props/state changes causing re-renders 🔍 Real example You click a button and suddenly the whole page re-renders. Profiler shows: 👉 A parent component updated 👉 All child components re-rendered 👉 Even the ones that didn’t need to 🚀 How to fix (after profiling) • Wrap components with React.memo • Use useMemo for heavy calculations • Use useCallback for stable functions • Avoid passing new object/array references 💡 Biggest mistake Optimizing blindly. Adding memoization everywhere… without knowing if it even helps. Measure → Identify → Optimize That’s the correct flow. 💡 React performance is not about writing more code. It’s about writing smarter code based on data. Have you ever used React Profiler to fix a real issue? 👇 #React #Frontend #WebPerformance #JavaScript #SoftwareEngineering #WebDevelopment