How to Debug React Performance with DevTools and Flame Graphs

Github: https://lnkd.in/gXq_-4mp 🔥 Project 2/20 — Sticky Header + Scroll Reveal ✨ Today we’re leveling up UI fundamentals. No React, no Tailwind — just pure HTML, CSS & JavaScript flexing its muscles. This sticky navbar transforms as you scroll, paired with silky smooth reveal animations using the Intersection Observer API. Modern devs love frameworks. Great devs master fundamentals first. And we’re building the foundation brick by brick — one clean UI at a time. Because good code isn’t just written — it’s crafted. 📌 Concepts: ✅ Scroll events ✅ Intersection Observer ✅ DOM manipulation ✅ UI animations 🔗 GitHub repo in bio Follow along — 18 more fire projects coming. We’re not coding… we're forging skills. ⚔️🔥 #javascript #webdevelopment #frontend #htmlcssjavascript  #uiuxdesign #frontendprojects #stickyheader #scrollanimation  #vanillajs #cssanimations #intersectionobserver  #learningtocode #webdevjourney #codingreels #codetutorial  #githubproject #frontenddeveloper #webdesign  #softwareengineer #programminglife #buildinpublic  #100daysofcode #devcommunity #codewithme #codeweaver

⚛️ useEffect — A Simple Breakdown That Finally Made Sense for Me Today I revised useEffect, and I focused on understanding when and why it runs. Once you look at it step-by-step, it feels much more predictable. 🔹 Here’s the simple flow: 1️⃣ It runs after the component renders 2️⃣ It runs again when the values in the dependency array change 3️⃣ If there’s a cleanup function, that runs when the component unmounts 🔹 Dependency Array Cheat Sheet: [] → run only on mount [count] → run when count updates no array → run on every render (not common) 🔹 Cleanup Example: Useful for timers, subscriptions, or event listeners. useEffect(() => { const id = setInterval(() => { console.log("Boring (: ..."); }, 1000); return () => clearInterval(id); // cleanup }, []); Understanding this flow makes React feel smoother to work with. Learning the “why” behind hooks really helps in writing predictable and clean components. #ReactJS #useEffect #Hooks #FrontendDevelopment #WebDevelopment #JavaScript #BuildingInPublic #100DaysOfCode

Every developer starts somewhere — and sometimes, it begins with a small project like this. In this week’s Code Challenge, we’re building a Dark Mode Toggle using only HTML, CSS, and JavaScript. No frameworks. No shortcuts. Just hands-on coding that builds real skills. You’ll learn how to: 🔸 Connect your web files properly 🔸 Make your site interactive with event listeners 🔸 Switch between themes dynamically 🔸 Design your own custom light and dark modes If you’re transitioning into tech, challenges like this help you think like a developer — not just follow a tutorial. ▶️ Watch Make Your Website Dark Mode Toggle on our Youtube Channel: https://lnkd.in/gqH8Yyys 👉 Start your journey: https://lnkd.in/gqumMgu6 #CodeClassroom #CareerSwitch #LearnToCode #FrontendDevelopment #CodingChallenge

JavaScript Promise.race() — When Speed Matters! Sometimes, you don’t need all async tasks to finish — you just want the fastest one’s result That’s where Promise.race() comes in! 💡 Definition: Promise.race() takes an array of promises and returns the result of the first one that settles (either resolved or rejected). 🧩 Example: const fast = new Promise((resolve) => setTimeout(() => resolve("🚀 Fast task completed!"), 1000) ); const slow = new Promise((resolve) => setTimeout(() => resolve("🐢 Slow task completed!"), 3000) ); Promise.race([fast, slow]) .then((result) => console.log("Winner:", result)) .catch((error) => console.error("Error:", error)); ✅ Output: Winner: 🚀 Fast task completed! Even though the slow promise finishes later, the first one decides the result. Why Use It? ✅ Get quick responses from multiple sources ✅ Useful in timeout or failover situations ✅ Improves user experience by reacting faster 🔖 #JavaScript #PromiseRace #AsyncProgramming #WebDevelopment #Frontend #JSConcepts #CodingTips #100DaysOfCode #KishoreLearnsJS #WebDevCommunity #DeveloperJourney #AsyncAwait

useEffect finally made sense when I realized it's just "do something after rendering" 💡 Spent weeks confused by useEffect. Docs talked about side effects, lifecycle methods, synchronization. Too abstract. Then someone explained it simply: React renders your component. Displays it on screen. THEN runs useEffect. That's it. Need to fetch data after component appears? useEffect. Need to update document title? useEffect. Need to start a timer? useEffect. Anything that happens AFTER the initial render goes in useEffect. The dependency array controls WHEN it runs again: Empty array? Only after first render. Never again. Has values? Runs after render IF those values changed since last time. No array? Runs after EVERY render (rarely what you want). Cleanup is just "undo what you did": Added event listener? Remove it in cleanup. Started timer? Clear it in cleanup. Opened connection? Close it in cleanup. My biggest useEffect mistakes: Putting fetch directly in component body instead of useEffect. Infinite loops. Forgetting the dependency array. Infinite loops again. Not cleaning up timers. Memory leaks everywhere. Missing dependencies. Stale data showing on screen. Making useEffect async. React errors. This guide covers: What useEffect actually does (simple explanation) When to use it vs when not to Dependency arrays without the confusion Cleanup functions explained clearly Every mistake I made learning this useEffect isn't scary once you understand: render first, effects second. #ReactJS #WebDevelopment #JavaScript #useEffect #ReactHooks #LearningReact

🔥 Loop Optimization in JavaScript — Code Smarter, Run Faster (2025 Edition) Loops are the heartbeat of your JavaScript logic and optimizing them can make your entire site feel snappier. Let’s level up your performance game 👇 1️⃣ Stick with the Classic for Loop: It’s old-school but still unbeaten for large datasets. Cache your arr.length and let your loops fly! 2️⃣ Readability Wins Too — Use map(), filter(), reduce(): Not every battle is about speed. These methods make your code clean, modern, and maintainable — perfect for smaller or non-critical processes. 3️⃣ Skip forEach() When Every Millisecond Counts: forEach() looks neat but hides function call overheads. For mission-critical speed, go back to basics. 4️⃣ Flatten Those Nested Loops: Nested iterations are performance black holes. Flatten data structures or rethink your logic to cut unnecessary loops. 5️⃣ Break Big Jobs into Small Wins: Long-running loops freeze the UI. Break them into chunks: function runInSmallBatches(arr, size) { let i = 0; function batch() { const end = Math.min(i + size, arr.length); for (; i < end; i++) {} if (i < arr.length) setTimeout(batch, 0); } batch(); } ⚡ Now your app breathes — smooth, responsive, and lag-free. Benchmark Everything. Don’t just “optimize” — prove it’s faster. Measure before and after. 💬 Final Thought: Write code that’s not just smart — but feels lightning fast. 🚀 #JavaScript #WebPerformance #CodingTips #FrontendDevelopment #SoftwareEngineering #WebOptimization #Programming #CodeBetter #JSPerformance #WebDev #TechTips #CleanCode #DevelopersLife #PerformanceMatters

🚀 Understanding React Class Component Lifecycle In React, Class Components have a well-defined lifecycle — a sequence of methods that run during the component’s creation, update, and removal from the DOM. Knowing these lifecycle methods helps developers control how components behave and interact with data at each stage. 🔹 1. Mounting Phase – When the component is created and inserted into the DOM. ➡️ constructor() – Initializes state and binds methods. ➡️ render() – Returns JSX to display UI. ➡️ componentDidMount() – Invoked after the component mounts; ideal for API calls or setting up subscriptions. 🔹 2. Updating Phase – When props or state changes cause a re-render. ➡️ shouldComponentUpdate() – Decides if the component should re-render. ➡️ render() – Re-renders the updated UI. ➡️ componentDidUpdate() – Called after re-render; perfect for DOM updates or data fetching based on previous props/state. 🔹 3. Unmounting Phase – When the component is removed from the DOM. ➡️ componentWillUnmount() – Used to clean up (like removing event listeners or canceling API calls). 💡 Example: I recently implemented lifecycle methods in a project to fetch product data using componentDidMount() from a fake API(https://lnkd.in/gkFvXQV6) and dynamically display it on the UI. It helped me understand how React efficiently handles rendering and updates. 10000 Coders Meghana M #ReactJS #WebDevelopment #Frontend #Learning #ReactLifecycle #JavaScript #CodingJourney

Why Clean Code Isn’t Always Fast Code We all love clean, modular React code, it’s easy to read, test, and maintain. But sometimes, that same “clean” structure quietly slows your app down. Here’s what I’ve learned over time 🔹 Too many abstractions = too many renders Breaking every small piece into its own component sounds ideal, but each component adds rendering overhead. Sometimes a few well-placed inline conditions perform better. 🔹 Hooks can hide performance issues A neat useCustomHook may look elegant, but if it recalculates heavy logic on every render, that abstraction hurts more than it helps. 🔹 Context isn’t free Global context updates can trigger re-renders across the tree. Sometimes prop drilling or selective memoization is the faster choice. 🔹 Clean != Optimal Readable patterns like .map() or .filter() chains look great but can be replaced with a single efficient loop when performance really matters. The key insight: Clean code is about humans reading it. Fast code is about machines executing it. #React #frontend #Web #code #Javascript #WebDev #interview

Understanding Microtasks & Macrotasks in JavaScript — The Event Loop Secret! Ever wondered how JavaScript handles async operations like Promises, timeouts, or fetch calls? 🤔 It’s all managed by the Event Loop, which uses two main types of queues — Microtasks and Macrotasks. 💡 Definition: Microtasks: Tasks that run immediately after the current script, before any rendering. 👉 Includes Promises, MutationObservers, and queueMicrotask(). Macrotasks: Tasks that run after the current event loop cycle, often with a small delay. 👉 Includes setTimeout, setInterval, setImmediate, and I/O tasks. 🧩 Example: console.log("1️⃣ Script start"); setTimeout(() => console.log("4️⃣ setTimeout (Macrotask)"), 0); Promise.resolve().then(() => console.log("3️⃣ Promise (Microtask)")); console.log("2️⃣ Script end"); ✅ Output: 1️⃣ Script start 2️⃣ Script end 3️⃣ Promise (Microtask) 4️⃣ setTimeout (Macrotask) Notice how Promise (Microtask) runs before setTimeout — that’s how the event loop prioritizes microtasks 🚀 ⚙️ Why It’s Important: ✅ Helps you understand async behavior ✅ Prevents performance issues ✅ Explains why Promises run before timers 🔖 #JavaScript #EventLoop #Microtasks #Macrotasks #AsyncProgramming #WebDevelopment #Frontend #JSConcepts #CodingTips #100DaysOfCode #KishoreLearnsJS #DeveloperJourney #WebDevCommunity

𝟭𝟱 𝗛𝗼𝘂𝗿𝘀 𝗜𝗻: Part 2 Complete! Mastering the DOM and Browser Interactivity 🚀 I'm thrilled to announce I've just completed the 7-hour "JavaScript Learn Everything Part 2" video from the Sheryians Coding School YouTube channel! A huge thank you to Harsh Vandana Sharma for another incredibly detailed marathon session. This part was all about bridging the gap between JavaScript logic and the live web page. We've officially moved from the console to creating dynamic, interactive user experiences. Here's a summary of the critical topics we mastered: 𝗧𝗵𝗲 𝗗𝗢𝗠 (𝗗𝗼𝗰𝘂𝗺𝗲𝗻𝘁 𝗢𝗯𝗷𝗲𝗰𝘁 𝗠𝗼𝗱𝗲𝗹): Finally, we learned how to "talk" to the website! We covered selecting elements, traversing the DOM tree, and dynamically adding, removing, or changing any HTML/CSS on the page. 𝗘𝘃𝗲𝗻𝘁𝘀 & 𝗘𝘃𝗲𝗻𝘁 𝗛𝗮𝗻𝗱𝗹𝗶𝗻𝗴: This is where the magic happens. We learned how to listen and react to user actions like clicks, scrolls, keypresses, and form submissions using event listeners. 𝗙𝗼𝗿𝗺𝘀 & 𝗙𝗼𝗿𝗺 𝗩𝗮𝗹𝗶𝗱𝗮𝘁𝗶𝗼𝗻: We put our DOM and event skills to practical use by learning to capture user input from forms and validate it in real-time, ensuring data is clean before it's ever submitted. 𝗪𝗲𝗯 𝗦𝘁𝗼𝗿𝗮𝗴𝗲 (𝗹𝗼𝗰𝗮𝗹𝗦𝘁𝗼𝗿𝗮𝗴𝗲, 𝘀𝗲𝘀𝘀𝗶𝗼𝗻𝗦𝘁𝗼𝗿𝗮𝗴𝗲, & 𝗖𝗼𝗼𝗸𝗶𝗲𝘀): A crucial deep dive into how browsers "remember" data. We learned the differences between these methods and when to use them to save user preferences, tokens, or session info. 𝗧𝗶𝗺𝗲𝗿𝘀 & 𝗜𝗻𝘁𝗲𝗿𝘃𝗮𝗹𝘀: A deeper look at asynchronous JavaScript with setTimeout and setInterval for timing-based events. 𝗕𝗼𝗻𝘂𝘀 𝗣𝗿𝗮𝗰𝘁𝗶𝗰𝗲 𝗤𝘂𝗲𝘀𝘁𝗶𝗼𝗻𝘀: The session wrapped with a ton of practical questions that helped solidify all these new concepts. Completing this section feels like a huge level-up. I'm no longer just writing logic; I'm building interactive applications. Can't wait for Part 3! #JavaScript #DOM #WebDevelopment #Frontend #CodingJourney #AIpoweredCohort #SheryiansCodingSchool #HarshVandanSharma #LocalStorage #EventHandling #WebDev