Debugging React Component Re-Renders with setState

𝐈 𝐬𝐩𝐞𝐧𝐭 𝐚𝐥𝐦𝐨𝐬𝐭 𝟑 𝐡𝐨𝐮𝐫𝐬 𝐝𝐞𝐛𝐮𝐠𝐠𝐢𝐧𝐠 𝐚 𝐑𝐞𝐚𝐜𝐭 𝐢𝐬𝐬𝐮𝐞. 𝐓𝐡𝐞 𝐟𝐢𝐱 𝐰𝐚𝐬 𝐨𝐧𝐞 𝐦𝐢𝐬𝐬𝐢𝐧𝐠 𝐝𝐞𝐩𝐞𝐧𝐝𝐞𝐧𝐜𝐲. The component looked correct. State was updating. The API call worked. But the UI refused to re-render. At first, I suspected the API response. Then I checked state updates. Everything seemed fine. The real problem was hiding in plain sight. My useEffect dependency array was incomplete. React wasn’t re-running the effect because the value it depended on wasn’t listed. One small detail. Hours of confusion. That moment reminded me of something simple about debugging: Most bugs aren’t complicated. They’re precise. The system is doing exactly what we told it to do — not what we expected. Curious how others approach this. 𝐖𝐡𝐚𝐭’𝐬 𝐭𝐡𝐞 𝐬𝐦𝐚𝐥𝐥𝐞𝐬𝐭 𝐦𝐢𝐬𝐭𝐚𝐤𝐞 𝐭𝐡𝐚𝐭 𝐜𝐚𝐮𝐬𝐞𝐝 𝐲𝐨𝐮 𝐭𝐡𝐞 𝐛𝐢𝐠𝐠𝐞𝐬𝐭 𝐝𝐞𝐛𝐮𝐠𝐠𝐢𝐧𝐠 𝐬𝐞𝐬𝐬𝐢𝐨𝐧? #ReactJS #Debugging #FrontendDevelopment

I built a feature that didn’t work the first 3 times. Here’s what it taught me 👇 While working on a React project, I faced repeated re-render issues that were killing performance. The fix wasn’t rewriting everything. It was: • Understanding component lifecycle • Fixing dependency arrays • Memoizing where necessary • Measuring before optimising Lesson: Debugging builds better engineers than tutorials ever will. What’s one bug that taught you the most? #WebDevelopment #FrontendDeveloper #FullStackDeveloper #ReactJS #MERNStack

𝗜 𝘂𝘀𝗲𝗱 𝘁𝗼 𝘁𝗵𝗶𝗻𝗸 𝗰𝗼𝗻𝘀𝗼𝗹𝗲.𝗹𝗼𝗴('𝗵𝗲𝗿𝗲') 𝘄𝗮𝘀 𝗮 𝗱𝗲𝗯𝘂𝗴𝗴𝗶𝗻𝗴 𝘀𝘁𝗿𝗮𝘁𝗲𝗴𝘆. 𝗜 𝘄𝗮𝘀 𝘄𝗿𝗼𝗻𝗴. When I first started with React Native, my code was littered with: console.log("111111") console.log("reached here") console.log("data", res) Fast forward to my time at development, and my perspective on "𝗱𝗲𝗯𝘂𝗴𝗴𝗶𝗻𝗴" has completely shifted. In a production-grade app, if you are relying solely on terminal logs, you aren't just slow—you’re likely missing the real bottleneck. 𝗧𝗵𝗲 𝗘𝘃𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝗼𝗳 𝗮 𝗥𝗲𝗮𝗰𝘁 𝗡𝗮𝘁𝗶𝘃𝗲 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿: 🔴 𝗧𝗵𝗲 𝗝𝘂𝗻𝗶𝗼𝗿 𝗣𝗵𝗮𝘀𝗲:  • Debugging by trial and error.  • c𝗼𝗻𝘀𝗼𝗹𝗲.𝗹𝗼𝗴 everywhere (and forgetting to remove them before the PR).  • Fixing the "symptom" instead of the "cause."  • Thinking a 60fps drop is just "the emulator lagging." 🟢 𝗧𝗵𝗲 𝗦𝗲𝗻𝗶𝗼𝗿 𝗣𝗵𝗮𝘀𝗲 (𝗧𝗵𝗲 𝗗𝗲𝘃𝘀𝗶𝗻𝗰 𝗦𝘁𝗮𝗻𝗱𝗮𝗿𝗱):  • Flipper & React DevTools: Inspecting the component tree and tracking unnecessary re-renders.  • Performance Monitor: Watching the JS thread vs. UI thread like a hawk to identify frame drops.  • Network Inspector: Not just seeing "if" the API worked, but checking the payload size and response time.  • Memory Leaks: Using the "Memory" tab to find why the app crashes after 10 minutes of usage. The difference between a Junior and a Senior dev isn't just about how many libraries you know; it’s about the tools you use to find the truth when things go wrong. 𝗤𝘂𝗲𝘀𝘁𝗶𝗼𝗻 𝗳𝗼𝗿 𝘁𝗵𝗲 𝗱𝗲𝘃𝘀: What is your "holy grail" debugging tool? Are you a Flipper fan, or do you still have a soft spot for the classic 𝗰𝗼𝗻𝘀𝗼𝗹𝗲.𝗹𝗼𝗴? #Devsinc #ReactNative #MobileDev #Debugging #SoftwareEngineering #PerformanceOptimization #Javascript #CodingLife

The most important skill for a developer is not coding. It's debugging. Because writing code is the easy part. Understanding why something broke is where real engineering begins. A good developer asks questions like: Why is this state not updating? Why is this API returning a 200 but the UI is empty? Why is this component re-rendering 50 times? Debugging turns you into a problem investigator. Some tools every frontend developer should master: 🔹 Browser DevTools Breakpoints Network inspection Performance analysis 🔹 React DevTools Inspect component hierarchy Track state & props Detect unnecessary re-renders 🔹 Redux DevTools Action tracing Time travel debugging 🔹 Console tools console.log console.table console.trace Great developers don't panic when things break. They open DevTools. #Debugging #FrontendDevelopment #ReactJS #JavaScript

I spent 4 hours debugging a bug that didn't exist. The real problem was something I had completely ignored. Here's what happened 👇 I was working on my IGclone project. Integrating the frontend with the backend login API. Hit the login button. Got a 401. Checked the console → only saw: TypeError: async/sync mismatch No "wrong password." No "invalid credentials." Nothing useful. So I did what most beginners do. I started questioning my entire async/await logic. Rewrote the auth flow. Compared with old Stack Overflow answers. 4 hours gone. Nothing fixed. Then I opened Chrome DevTools → Network tab → clicked the /api/login call → went to Preview tab. It said: "message": "Wrong password" I had typed the wrong password. That's it. That was the entire bug. Here's what I actually learned that day: 1️⃣ Always send meaningful error messages from your backend 401 is just a number. The frontend needs context. Return "Wrong password" or "User not found" not just a status code. 2️⃣ Frontend must display those messages properly If the UI only shows a generic error, you're hiding the truth from the user and from yourself at 2AM. 3️⃣ Chrome DevTools Network tab is underrated Most beginners only check the Console. The real answer is usually in Network → Preview. You see exactly what the server returned. 4️⃣ Before rewriting logic check the actual data first The bug is rarely where you're looking. Check the API response before touching the code. One missing error message cost me half a day. Now every API I write returns a message field. No exceptions. If your backend stays silent when something goes wrong it's not done yet. still building, still learning. What’s the most ridiculous bug you’ve spent hours debugging? #WebDevelopment #JavaScript #BackendDevelopment #ReactJS #NodeJS #DebuggingTips #ChromeDevTools #100DaysOfCode #21DayChallenge #LearningInPublic

🚀 I built a VS Code extension that plays a “FAAAAH” sound on every error. As developers, we all know the feeling: Test fails ❌ npm install breaks ❌ Build crashes ❌ Syntax error in file ❌ So I built a lightweight VS Code extension that detects: • Terminal command failures • Task exit codes ≠ 0 • TypeScript / ESLint / runtime errors • Package installation failures And plays a dramatic “FAAAAH” sound instantly. It hooks into: onDidCloseTerminal onDidEndTaskProcess onDidChangeDiagnostics With cooldown control and toggle settings. Why? Because sometimes feedback should be: Immediate. Emotional. Memorable. Next version ideas: 🔹 Different sounds per error type 🔹 Failure counter 🔹 “Rage Mode” 🔹 Custom sound upload Building small dev tools like this is a great way to explore the VS Code Extension API deeply. Would you install it? 😄 Live : https://lnkd.in/gaUkZGum #VSCode #JavaScript #DeveloperTools #BuildInPublic #SideProject

Some silent bugs will humble you. You’ll be there, confident… then boom. Typing cont instead of const And you’ll stare at your screen for 30 minutes wondering who offended JavaScript. Array.from() This one? It showed me premium shege in one of my projects. Everything looked right… but nothing was working right. You’ll debug. You’ll console.log. You’ll question your life choices. Then DevTools will quietly save you like the real MVP. Big respect to the engineers who built browser developer tools. They don’t get enough credit. If you’re learning to code: It’s not always big complex logic that breaks your app. Sometimes… it’s one letter. Stay patient. Debugging is part of the journey. #FrontendDevelopment #JavaScript #WebDevelopment #BuildInPublic #DevLife

I made an MCP server for Three.js debugging because I wanted Three.js development to feel less manual. Most Three.js debugging is some variation of inspecting the scene tree, poking at materials, checking out lights and shadows, logging transforms, reloading, and doing it all over again. So, I made threejs-devtools-mcp. It connects Claude, Cursor, and Windsurf to your live Three.js app, enabling them to inspect your scene hierarchy, materials, shaders, lights, shadows, and performance stats, as well as modify values in real time, and convert GLTF to React Three Fiber JSX. It’s all about making bugs easier to catch by enabling AI to work with the actual runtime scene state, not just source code. Supports Three.js, React Three Fiber, and Next.js. Available now on npm and the official MCP Registry. GitHub: https://lnkd.in/d3MCbSgM npm: npx threejs-devtools-mcp Would love to hear back from other Three.js developers. #threejs #webgl #mcp #devtools #3d #webdev

Stop Writing Redux the Hard Way. I used to write 50+ lines of boilerplate just to manage a simple counter in Redux. Action types. Action creators. Switch statements. Immutable update logic. Then I discovered createSlice from Redux Toolkit — and everything changed. In under 15 lines, you get: Auto-generated action creators Auto-generated action types Immer-powered state mutations (yes, you can "mutate" state directly) A clean, readable reducer No more switch statements. No more ...state spread operators. No more separate action files. Redux Toolkit isn't just a convenience — it's the official, recommended way to write Redux in 2026. If you're still writing Redux the old way, you're working harder, not smarter. What's one tool that completely changed how you write code? Drop it below. 👇 #Redux #ReduxToolkit #JavaScript #React #WebDevelopment #Frontend #SoftwareEngineering #CodeSmarter #LearnToCode

Full-stack TypeScript with tRPC unlocks a level of type safety that most developers overlook — and it changes everything. If you want truly seamless end-to-end type safety, these three tips will sharpen your approach: 1. Define your API types **only once** in your tRPC router. When your backend routes and frontend queries share the same contract, your editor catches mismatches before they become bugs. No more duplicating DTOs or manual sync tasks. 2. Use tRPC’s `inferProcedureOutput` to extract response types dynamically. This avoids over-typing your frontend and keeps your code DRY. For example: ```ts type User = inferProcedureOutput<AppRouter['getUser']>; const user: User = await trpc.getUser.query({ id: '123' }); ``` 3. (Hidden gem) Combine tRPC with Zod schemas for runtime validation *and* type inference. Many devs use Zod only for validation, but it’s a powerhouse for guaranteed type safety in inputs and outputs. This reduces bugs that sneak past TypeScript’s static checks. In my last project, AI-assisted development helped me prototype a tRPC-powered full-stack app in under an hour, maintaining strict types throughout. That kind of speed and confidence? Game changer. Which of these was new to you? How do you maintain type safety in your full-stack projects? #WebDevelopment #TypeScript #Frontend #JavaScript