React's Virtual DOM: Faster Performance with Smarter Updates

If you think every re-render updates the DOM, this will change your mind. Rendering in React is just a function call. Your component runs, returns JSX, and React calculates what the UI should look like. That’s it. Now the important part 👇 Re-rendering does NOT mean the DOM was updated. It only means 👉 React called your component again The DOM is updated later and only if something actually changed. So the real flow is: Trigger → state or props change Render → React runs your component Commit → React updates only the differences This is why you can type inside an input, the component re-renders, and your text is still there. Because React doesn’t touch what hasn’t changed. The real optimization isn’t avoiding re-renders It’s understanding what happens after them. #React #FrontendDevelopment #JavaScript #WebDevelopment #SoftwareEngineering #ReactJS #FrontendEngineer #TechCareers #CodingTips #DeveloperMindset

React Rendering Flow — simplified 👇 Every UI update in React follows a structured process: ▪️ Trigger (state/props/event) ▪️ Virtual DOM creation ▪️ Diffing old vs new ▪️ Reconciliation ▪️ Efficient DOM update React doesn’t blindly update the DOM — it calculates the minimum changes needed. This is what makes React fast ⚡ Understanding this changed how I design components. What part of React internals do you find confusing? #React #FrontendDevelopment #WebDevelopment #JavaScript

Your component is re-rendered... Then what? Most developers stop thinking here. And that’s where the real magic starts. This is Post 3 of the series: 𝗥𝗲𝗮𝗰𝘁 𝗨𝗻𝗱𝗲𝗿 𝘁𝗵𝗲 𝗛𝗼𝗼𝗱 Where I explain what React is actually doing behind the scenes. React does NOT update the DOM immediately. Because touching the DOM is expensive. Instead, it follows a 3-step process: Render → Diff → Commit First, React creates something called a 𝗩𝗶𝗿𝘁𝘂𝗮𝗹 𝗗𝗢𝗠. Not the real DOM. Just a JavaScript object in memory. A blueprint of your UI. Every time your component runs, React builds a new tree of this Virtual DOM. And it already has the previous tree stored. Now comes the interesting part. React compares: Old tree vs New tree This step is called 𝗗𝗶𝗳𝗳𝗶𝗻𝗴. It finds exactly what changed. Not everything. Just the difference. Then comes the final step: 𝗖𝗼𝗺𝗺𝗶𝘁 phase React takes only those changes… …and updates the real browser DOM So no, React is NOT re-rendering your whole page. It’s doing surgical updates. The key insight: React separates thinking from doing. Thinking = Render + Diff Doing = Commit That’s why React is fast. Because touching the DOM is expensive. So React minimizes it. Flow looks like this: ✅️ Component runs ✅️ Virtual DOM created ✅️ Changes calculated ✅️ DOM updated ✅️ Browser paints UI Once you see this, you stop fearing re-renders. And start understanding them. In Post 4 of React Under the Hood: How does React actually compare trees? (The diffing algorithm 👀) Follow Farhaan Shaikh if you want to understand react more deeply. 👉 Read in detail here: https://lnkd.in/dTYAbM6n #React #Frontend #WebDevelopment #JavaScript #SoftwareEngineering

Topic: React Batching – Why Multiple setState Calls Don’t Always Re-render ⚡ React Batching – Multiple setState Calls, One Render (But Not Always) Ever written this and expected 2 re-renders? 👇 setCount(c => c + 1); setCount(c => c + 1); But React only re-renders once 🤯 Why? 👉 Batching 🔹 What is Batching? React groups multiple state updates and processes them in a single render cycle. 🔹 Why It Matters ✔ Better performance ✔ Fewer unnecessary renders ✔ Smoother UI updates 🔹 Before React 18 😓 Batching worked only in: 👉 Event handlers Not in: ❌ setTimeout ❌ Promises 🔹 After React 18+ 🚀 Automatic batching works almost everywhere: ✔ setTimeout ✔ async/await ✔ API calls 🔹 Example setTimeout(() => { setA(1); setB(2); }); 👉 Still only one render in modern React 💡 Important Note If you need immediate update: flushSync(() => setCount(1)); 📌 Golden Rule React tries to do more work in fewer renders. 💬 Did batching ever confuse you while debugging state updates? #React #ReactJS #StateManagement #FrontendDevelopment #JavaScript #WebDevelopment #DeveloperLife

The DOM is officially a bottleneck. 🤯 Cheng Lou (former React core team) just dropped Pretext, and it is challenging how browsers have handled text layout for the past 30 years. For decades, figuring out how much space a paragraph occupies meant rendering it in the browser and measuring it. This triggers layout reflows (using tools like getBoundingClientRect), which is one of the most expensive and thread-blocking operations in web development. Enter Pretext: A pure JavaScript/TypeScript library that handles multiline text measurement without touching the DOM. Here is why it is so powerful: Instead of relying on CSS rendering, it uses an off-screen Canvas and a clever two-phase API (prepare() and layout()) to pre-calculate word sizes using pure arithmetic. The layout operations run in roughly 0.09ms. It natively supports platform-specific emojis, complex text directions (RTL), and different languages. It enables previously impossible UI effects, like text fluidly wrapping around moving, draggable obstacles in real-time. The project rocketed past 10,000 GitHub stars in just days because it solves a massive performance hurdle for the next generation of spatial and interactive UIs. #WebDevelopment #JavaScript #TypeScript #Frontend #SoftwareEngineering #TechNews #UIUX

Today while building a pagination component in React, I came across the use of Array.from() in JavaScript. The problem I was facing was simple: I wanted to show page numbers between the Previous and Next buttons. For example: Prev 1 2 3 4 5 Next At first, I was thinking about how to generate those numbers dynamically instead of writing them manually. That’s when I came across Array.from(). It helped me create an array of a specific length and then generate page numbers from it. Something like this: Array.from({ length: totalPages }, (_, i) => i + 1) This creates: [1, 2, 3, 4, 5] Which can then be mapped easily to render pagination buttons in React. A small thing, but it made pagination logic feel much cleaner and more dynamic. Am I understanding this correctly? Would love to know if there’s a better or more practical way you usually handle pagination numbers. #JavaScript #ReactJS #WebDevelopment #Frontend #Pagination

Your UI lag is not always React. Sometimes… It’s the JavaScript event loop. Here’s what’s happening 👇 JavaScript is single-threaded. So when you run: → Heavy calculations → Large loops → Sync blocking code You block: ❌ Rendering ❌ User interactions Result: → UI freezes → Clicks feel delayed → App feels slow React can’t help here. Because it runs on the same thread. What works: ✔ Break work into chunks ✔ Use requestIdleCallback / setTimeout ✔ Offload heavy tasks (Web Workers) Key insight: Performance is not just “React optimization”. It’s understanding how the browser executes code. Ignore the event loop… And your UI will suffer. #JavaScript #EventLoop #Frontend #ReactJS #Performance #SoftwareEngineering #WebDevelopment #AdvancedReact #Engineering #Optimization

One line of JavaScript can change an entire user experience. Example: Updating text dynamically instead of reloading a page. Small concept — big impact. This is why frontend development is so powerful. #webdevelopment #frontenddeveloper

Built a to-do app with a glassmorphic UI as a mini project. Kept it simple — vanilla HTML, CSS, and JS. No frameworks. A few things I learned along the way: — Local Storage API to persist tasks on refresh — DOM manipulation with vanilla JS — How CSS backdrop-filter actually works for the glass effect — JSON.stringify and JSON.parse for saving arrays Small project but learned a lot from it. More coming. repo link: https://lnkd.in/dEtj35Us #WebDev #JavaScript #Frontend #BuildInPublic

🚀 Understanding Virtual DOM vs Real DOM in React — Simplified! If you're working with React, you've definitely heard this: 👉 “React is fast because of the Virtual DOM” But what does that actually mean? 💡 What is the Real DOM? The Real DOM is the actual structure of your webpage. 👉 Every change directly updates the browser DOM 👉 Even small updates can trigger reflow & repaint ❌ Slow for frequent updates ❌ Expensive operations 💡 What is the Virtual DOM? The Virtual DOM is a lightweight JavaScript representation of the Real DOM. 👉 React keeps a virtual copy in memory 👉 Updates happen in the Virtual DOM first ⚙️ How it works (React magic) 1️⃣ State changes trigger a re-render 2️⃣ React creates a new Virtual DOM tree 3️⃣ Compares it with the previous one (Diffing) 4️⃣ Updates ONLY the changed parts in Real DOM 👉 This process is called Reconciliation 🧠 Real-world example Imagine updating a list: ❌ Without Virtual DOM: Entire DOM may re-render ✅ With Virtual DOM: Only the changed item updates 🔥 Why Virtual DOM is faster ✔ Minimizes direct DOM manipulation ✔ Batches updates efficiently ✔ Updates only what actually changed ⚠️ Common Misconception 👉 Virtual DOM ≠ Always faster If used incorrectly: Unnecessary re-renders can still slow your app 🔥 Best Practices ✅ Avoid unnecessary state updates ✅ Use keys properly in lists ✅ Optimize re-renders (memo, useCallback) ❌ Don’t assume React auto-optimizes everything 💬 Pro Insight React is not fast because of Virtual DOM alone— 👉 It’s fast because of smart diffing + efficient updates 📌 Save this post & follow for more deep frontend insights! 📅 Day 6/100 #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #ReactInternals #SoftwareEngineering #100DaysOfCode 🚀