Prevent Unnecessary React Rerenders with React.memo

💡 𝗧𝗶𝗽 𝗼𝗳 𝘁𝗵𝗲 𝗗𝗮𝘆 — 𝗥𝗲𝗮𝗰𝘁 𝗗𝗶𝗱 𝘆𝗼𝘂 𝗸𝗻𝗼𝘄? In React, 𝗳𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝘀 𝗱𝗲𝗳𝗶𝗻𝗲𝗱 𝗶𝗻𝘀𝗶𝗱𝗲 𝗰𝗼𝗺𝗽𝗼𝗻𝗲𝗻𝘁𝘀 𝗮𝗿𝗲 𝗿𝗲𝗰𝗿𝗲𝗮𝘁𝗲𝗱 𝗼𝗻 𝗲𝘃𝗲𝗿𝘆 𝗿𝗲𝗻𝗱𝗲𝗿. This means passing them as props can trigger unnecessary re-renders in child components. 🔧 𝗕𝗲𝘀𝘁 𝗽𝗿𝗮𝗰𝘁𝗶𝗰𝗲: - Use "useCallback" to memoize functions when passing them down - Only do this when necessary (e.g., with "React.memo" or dependency arrays) Not every function needs memoization—but knowing when it matters is key. #React #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #PerformanceOptimization #SoftwareEngineering #CodingTips #FullstackDeveloper

📌 Part 8 of 10: A lot of React bugs make more sense once you realize state behaves more like a snapshot than a live variable. That idea sounds small. But once it clicks, a lot of confusing behavior starts making more sense. Why logs can feel misleading. Why updates don’t look immediate. Why handlers sometimes “see” older values than people expect. Once I really understood that, I stopped fighting React as much. I started designing with it instead. What React concept took longer to click for you than expected? #React #ReactJS #StateManagement #JavaScript #FrontendDevelopment #Debugging #TypeScript

Why does React say: "Don't call hooks conditionally"? 🤔 Let’s break it down simply. React doesn’t track hooks by name. It tracks them by order. Every render, React just walks through hooks like this: 1st hook → 2nd hook → 3rd hook That’s it. No labels. No IDs. Just position. Now imagine this 👇 if (condition) { useEffect(() => { // do something }); } 👉 First render: Hook1 → Hook2 → Hook3 👉 Next render (condition = false): Hook1 → Hook3 Now React gets confused 😵 It expects Hook2… but suddenly sees Hook3. This breaks the internal hook mapping — and boom 💥 unexpected bugs or crashes. 👉 The rule exists because hooks must run in the same order on every render. That’s why: ❌ No hooks inside conditions ❌ No hooks inside loops ❌ No hooks inside nested functions 👉 Always call hooks at the top level. Once you understand this, React hooks feel much less “magical” and more predictable. #ReactJS #JavaScript #FrontendDevelopment #WebDevelopment #LearnInPublic

🚨 Small React mistake… big headache 👇 I used to write code like this without even thinking: if (condition) return null; useEffect(() => { // logic }, []); It looks completely fine, right? I thought the same ❌ Then suddenly this error shows up: 👉 "Rendered fewer hooks than expected" Took me some time to realize what was actually wrong. React expects hooks to run in the same order every single render. But in this case: • First render → component returns early → useEffect doesn’t run • Next render → useEffect runs And boom 💥 React gets confused because the order changed. The fix is simple (but easy to forget): useEffect(() => { // logic }, []); if (condition) return null; Now hooks always run first, no matter what 👍 💡 Lesson learned: Never put hooks after a condition or inside it. Always keep them at the top. Have you ever hit this error? It’s one of those bugs that looks small but wastes a lot of time 😅 #react #nextjs #javascript #frontend #webdev

If your React component has isLoading, isError, isEmpty and isSuccess as separate props, you have a problem. I have written this exact code. More than once. It starts small. You add isLoading to show a spinner. Then isError for the error state. Then isEmpty because the empty state needs its own UI. Then isSuccess for the confirmation screen. Now you have four boolean props. And they fight each other. What happens when isLoading and isError are both true? Which one wins? Nobody knows. The component does not know either. You just hope the parent passes the right combination. This is Boolean Prop Hell. And it is sitting in most React codebases right now. Booleans feel simple but they hide impossible states. 4 boolean props = 16 possible combinations. Your component can only handle maybe 4 of them. The other 12 are bugs waiting to happen. Replace all of them with a single status prop. One value. One source of truth. No impossible combinations. The component always knows exactly what to render. This is how every serious component library handles it. There is a reason for that. When you find yourself adding another boolean prop, stop for a second. Ask: is this a new state or just a variation of an existing one? Most of the time you do not need a new prop. You need a better status model. Before and after in the screenshot below 👇 #ReactJS #Frontend #WebDev #JavaScript

⚛️🚀Building reusable components is one of the best ways to write cleaner, scalable React code. In my latest blog, I break down how I created a dynamic, beginner‑friendly button component that adapts based on props—no more repeating the same markup. From conditional rendering to flexible class handling, this approach keeps your UI consistent and efficient. A great starting point for anyone improving their React workflow! https://lnkd.in/djJWMbZj #ReactJS #WebDevelopment #FrontendDev #ReusableComponents #JavaScript #CleanCode #ReactTips #TailwindCSS #CodingJourney #SoftwareEngineering

Unpopular opinion: you don't need to learn every JavaScript framework. I spent months anxious that I wasn't learning fast enough. React came out with something new. A new framework dropped. Everyone was talking about it. Here's what I wish someone told me earlier: > Pick one thing. Get genuinely good at it. Then expand. > I focused on React and CSS fundamentals for my first year. That decision paid off more than chasing every trend. > The frontend ecosystem moves fast. That's exciting — but it's also a trap if you're not careful. What's the one thing you wish you'd focused on earlier? #JavaScript #React #Frontend #WebDevelopment #LessonsLearned

Why does React feel so fast? ⚛️🚀 It’s not just about the Virtual DOM 👇 • Calculates minimal changes • Updates only what’s needed • Batches multiple updates • Avoids unnecessary re-renders 👉 Result: Faster and smoother UI In simple terms: React updates only the changed part, not the whole page. #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #MERNStack #SoftwareEngineering

One small React habit that improved my code a lot: Stop putting everything in one component. Earlier, I used to write large components with too much logic. It worked… but became messy very quickly. Now I try to: • Break UI into smaller components • Keep logic separate • Reuse components wherever possible This makes the code cleaner and easier to scale. If you're learning React, start thinking in components, not pages. #reactjs #frontend #webdevelopment #javascript

most developers don't know the difference between null , undefined and "" and it's breaking their React forms silently. - always initialise string state with ' ' not undefined - always initialise array state with [ ] not undefined - always initialise object state with { } not undefined here's why it matters beyond the warning: - undefined means "this was never set" - null means "this was intentionally set to nothing" - ' ' means "this exists but is currently empty" React treats these three things completely differently when rendering. your form works locally because you fill it in immediately. it breaks in production because someone submits without touching a field. initialise your state properly. #reactjs #typescript #webdevelopment #buildinpublic #javascript