How React Reconciliation Works: A Guide to Efficient Updates

In React, why does changing the ref value not trigger multiple re-renders? Let's discuss what happens under the hood in React. 1. React initializes the ref object with initialValue defined in the code. 2. The ref object is saved in the memoizeState property of the hook node in the linked list of hooks. 3. The hooks linked list is internally managed by React with the order in which we define hooks in the component's code. 4. If useRef is the first hook, its data will get saved on memoizedState property of an internal structure called currentlyRenderingFiber which refers to the fiber node of the component currently being rendered. 5. Otherwise, the work-in-progress pointer will add useRef to the hooks linked list as per the order of the hooks in the code. 6. WorkInProgress is an internal pointer to traverse the hooks linked list, add a new hook during the first render, or reuse/clone existing ones during re-rendering. 7. React maintains hooks in a linked list so that the order of hooks doesn't get changed. When rerender happens 1. The React updateRef method is called internally, and the WorkInProgress pointer traverses through the hooks linked list, finds, and returns the same memoizedState node against which ref was initially defined. Points no. 4, 5, and 6 might feel quite overwhelming; I will discuss these in the coming days. I do a deep dive into foundational concepts & how things work under the hood. You can consider connecting with or following me, Ali Raza, to get along with the journey. #react #javascript #frontend #nextjs

🚀 Understanding the Trio: useState vs useRef vs useReducer in React As React developers, we often juggle between these three — but when to use which? Let’s break it down 👇 🧠 useState > When you need to track simple, reactive state changes that trigger re-renders. 📌 Example: toggling a theme, updating input fields, counters, etc. const [count, setCount] = useState(0); ⚡ useRef > When you need to store a value that persists across renders without re-rendering the component. 📌 Example: accessing DOM elements, storing previous state, timers, etc. const inputRef = useRef(); 🛠️ useReducer > When your state logic becomes complex — involving multiple transitions or actions. 📌 Example: managing forms, API states, or any state with multiple sub-values. const [state, dispatch] = useReducer(reducerFn, initialState); 💡 Quick Summary Hook Triggers Re-render Use Case useState ✅ Yes Simple UI updates useRef ❌ No DOM refs or mutable values useReducer ✅ Yes Complex state logic 🎯 Pro Tip: If you find useState getting messy with multiple variables — it’s probably time to switch to useReducer. #ReactJS #FrontendDevelopment #ReactHooks #WebDevelopment #JavaScript

⚛️ Top Mistakes Developers Often Make in React.js (and How to Avoid Them) 🚫 No matter how long we’ve been coding, we’ve all made these mistakes at some point 👇 1️⃣ Not Using Keys Properly in Lists → Missing or using index as a key can cause re-rendering issues. ✅ Always use a unique id instead. 2️⃣ Mutating State Directly → Doing state.value = newValue won’t trigger a re-render. ✅ Always use the state setter (e.g., setValue(newValue)). 3️⃣ Overusing useEffect → Putting too much logic inside useEffect can lead to performance problems or infinite loops. ✅ Keep it focused — and always define dependencies properly. 4️⃣ Ignoring Component Reusability → Rewriting similar code multiple times. ✅ Break your UI into smaller, reusable components. 5️⃣ Not Handling Async Code Correctly → Forgetting to clean up async calls can cause memory leaks. ✅ Use cleanup functions or cancel tokens. 6️⃣ Forgetting Error Boundaries → A single runtime error can crash your entire UI. ✅ Wrap components in error boundaries for safety. Every mistake teaches something new — the key is to learn, refactor, and grow. 💪 What’s the biggest React mistake you made early on? 👇 #ReactJS #FrontendDevelopment #WebDevelopment #JavaScript #CodingTips

🚀 Remix 3 ditched React — should you stick with it? 💡 Key takeaways: ✨ Remix 3 is a complete rewrite, moving away from React to a Preact-based, web-standard model. ⚙️ It introduces an imperative approach (this.update()) instead of Hooks like useState. 🤖 The new focus is being “LLM-friendly”, simplifying code for both humans and AI. 🛤️ Developers now face two paths: 🔹 React Router v7 → Stable, React-based continuation. 🔹 Remix v3 → Experimental, React-less future. 🔥 It echoes Angular’s 2016 reboot — a bold gamble for modernization. 🤔 Is Remix 3 a revolutionary step forward or a risky detour? 👉 Read the full analysis here: https://lnkd.in/dhwakX9A #React #Remix #FrontendDevelopment #WebDev #JavaScript #Preact #Developers

Did you know that before React Fragments existed, developers had to wrap multiple JSX elements in an array just to render them side by side? Something like this 👇 return [ <Header key="header" />, <Main key="main" />, <Footer key="footer" /> ] We couldn’t return multiple elements directly from a component because JSX is syntactic sugar for React.createElement(), which returns a single React element tree. If you tried to return multiple siblings, React wouldn’t know what the “root” of that tree is — it needs one parent node to efficiently reconcile updates in the virtual DOM. So people started using unnecessary <div> wrappers — the infamous “div soup” — or arrays with keys to hack around it. Then came Fragments: return ( <> <Header /> <Main /> <Footer /> </> ) No extra DOM nodes. No extra noise. Just a clean, semantic structure. It’s a small feature, but one that made React components feel way more natural to write. #ReactJS #JavaScript #FrontendDevelopment #WebDevelopment #ReactTips

If you’re curious like me about how frontend web frameworks are built or how they work under the hood, this book is a great read “Build a Frontend Web Framework (From Scratch)”. I really enjoyed reading it! It’s fun, surprisingly comprehensive, and gives a clear mindset about what’s happening behind tools like React, Vue, or Svelte. It’s not about creating a production framework, it’s about learning by building, from the DOM to virtual DOM, state management, and reconciliation algorithms. Here’s a summary and key takeaways: 1. Frameworks aren’t magic Frameworks automate repetitive, low-level DOM work. When you build one from scratch, you realize they’re just organized layers of abstraction, not magic. 2. Start from the roots You begin by coding a small app with vanilla JavaScript, manually updating the DOM to understand what problems frameworks solve. 3. Virtual DOM & Reconciliation You then build a virtual DOM, a lightweight JS representation of the actual DOM. You learn how frameworks diff (compare) two virtual trees to apply minimal updates to the browser DOM, the same concept React uses. 4. State Management The book teaches a reducer-based state manager, similar to Redux’s idea: Centralized state Dispatch actions → reducers update state → re-render the view 5. Components You build functional and class-based components that: Hold their own state Re-render when state changes Can nest inside each other and communicate via props and events 6. Lifecycle & Scheduler Later chapters add lifecycle hooks (onMounted, onUnmounted) and an async scheduler to coordinate rendering, similar to Vue’s nextTick or React’s reconciliation cycle. 7. Advanced Concepts You also explore: Keyed lists (for efficient updates) Component communication Testing asynchronous components and extras like routing and slots in the GitHub wiki. Check it out here: [ https://lnkd.in/dquAstr6 ] #FrontendDevelopment #WebDevelopment #JavaScript #WebFramework #CodingBooks #SoftwareEngineering #ReactJs #FrontEndDeveloper #NextJs

🧩 Custom Hooks: The Hidden Superpower of React When React introduced hooks, it wasn’t just another API — it was a quiet revolution. ⚡ Before hooks, we wrote class components that grew like wild forests. Logic was tangled across lifecycles, duplicated, or hidden behind HOCs. Then came this little thing called useSomething(). Suddenly, we could extract logic like Lego blocks. 💡 The moment I truly understood React wasn’t when I learned useEffect. It was when I realized I could write my own. function useOnlineStatus() {  const [isOnline, setIsOnline] = useState(navigator.onLine);  useEffect(() => {   const updateStatus = () => setIsOnline(navigator.onLine);   window.addEventListener('online', updateStatus);   window.addEventListener('offline', updateStatus);   return () => {    window.removeEventListener('online', updateStatus);    window.removeEventListener('offline', updateStatus);   };  }, []);  return isOnline; } That’s not a utility — that’s architecture in disguise. Hooks make behavior composable, predictable, and testable. The biggest mistake developers make? Using built-in hooks forever but never writing their own. Once you start thinking in custom hooks, you stop building components — and start designing systems of logic. #ReactJS #Hooks #FrontendDevelopment #CleanCode #JavaScript #WebArchitecture #ReactDesignPatterns #SystemDesign

🚀 React Hooks: The Evolution in Front-end Development If you work with React, deeply understanding the role of React Hooks is essential. They marked a fundamental shift in how we build components, making our code cleaner and more functional. What Are React Hooks? At their core, React Hooks are functions that allow us to use features like state and side effects directly within functional components. Before Hooks (introduced in React 16.8), state and lifecycle management were the exclusive domain of class components, which required using this.state and the often-verbose this.setState. 💡 The Crucial Difference: Unifying Logic The main strength of Hooks is how they organize logic, which contrasts sharply with class lifecycle methods. In class components, logic was fragmented and spread across multiple methods (componentDidMount, componentDidUpdate, componentWillUnmount). With Hooks like useEffect, this logic is unified. We can group related functionality (such as fetching data, setting up, or cleaning up subscriptions) into a single block. This results in code that is more cohesive, easier to trace, and simpler to maintain. ✨ The Power of Simplicity and Reusability Simplified State: useState allows state management directly in functional components, eliminating the complexity of this and classes. Clean Code: Without the need for classes and boilerplate, the code becomes more concise and readable. Easy Reusability: We can create Custom Hooks to isolate and reuse complex state logic across different parts of the application. In summary: React Hooks have cemented functional components as the best practice in the React ecosystem, bringing simplicity and efficiency to our daily work. #React #JavaScript #Frontend #WebDevelopment #ReactHooks

🚀 React 19.2 just made forms feel… modern. One of the coolest new things is built-in form actions. Now you can handle form submissions without useState, useEffect, or tons of boilerplate. That means: ✅ less code ✅ fewer bugs ✅ cleaner async logic Here’s the vibe 👇 <form action={async (formData) => { const res = await fetch('/api/send', { method: 'POST', body: formData, }) }}> <input name="email" placeholder="Enter your email" /> <button type="submit">Subscribe</button> </form> That’s it — no state, no handlers, no custom hooks. React automatically handles submission, loading, and even errors — while keeping the UI responsive. In 2025, this feels like React finally catching up with how we actually build products — fast, declarative, and server-first. #React #Frontend #JavaScript #Nextjs #WebDevelopment #React19

React’s pain points often stem from JavaScript itself: reference equality drives a memoization cascade (think useCallback and useMemo everywhere), and even the React Compiler only partially helps. The article argues that the lack of structural equality causes unnecessary re-renders and correctness bugs, explains the limits of compiler automation, and makes the case for pushing business logic into a Rust + WebAssembly core while keeping React as a thin UI layer. Read the full article: https://lnkd.in/exrgP_UB #React #JavaScript #SoftwareArchitecture #WebAssembly #Rust