Akilesh Rao’s Post

Day 56 — Introduction to React.js: Building the Foundation of Modern Frontends Today marks the beginning of my journey into React.js, one of the most powerful JavaScript libraries for building interactive and dynamic user interfaces. ⚛️ I learned how React efficiently manages UI updates using the Virtual DOM, how everything in React revolves around components, and how JSX brings HTML-like syntax into JavaScript for seamless UI creation. I also set up my React environment using Vite (faster alternative to CRA) and explored the initial folder structure — getting hands-on with my first React component. 🧩 Key Concepts Covered What is React and why it’s component-based Virtual DOM vs Real DOM JSX syntax and rendering React project setup using npm create vite@latest my-app Folder overview: src, App.jsx, and index.jsx ⚙️ Sample Code: Hello React Component function App() { return ( <div> <h1>Welcome to React 🚀</h1> <p>Building interactive UIs made simple!</p> </div> ); } export default App; 🎯 Next Up Tomorrow, I’ll dive into Functional Components & Props — the building blocks of modular UI design. #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #LearningJourney #ReactBeginners #Vite #CodingCommunity #UIUX #TechGrowth #100DaysOfCode #cfbr

🧠 Let’s talk about one of the most fundamental concepts in React: useState. If you’ve ever built an interactive UI, a counter, a form, a toggle, or even a shopping cart, you’ve already relied on the idea of state: data that changes over time. In React, useState is the hook that lets us handle that dynamic data inside components. It gives you two things: 1- The current state value 2- A function to update it Every time you call that update function, React re-renders your component with the new value, and that’s how your UI stays in sync. ⚙️ Why useState matters: - It turns static interfaces into interactive ones. - It helps React know when and what to re-render. - It keeps your logic clean and contained within each component. You don’t need external libraries or complex data layers to handle simple interactivity, useState alone can take you far. To demonstrate this, I built a small educational project: ==> Multi Counter App It’s a simple React app where you can: - Add multiple counters dynamically - Increment or decrement each one - Remove counters when you’re done Each counter is managed by React’s useState, showing exactly how you can handle dynamic arrays and updates in a clean, immutable way. You can check it out here 👇 🔗 GitHub Repo [https://lnkd.in/dt3cq9vG] Whether you’re new to React or brushing up your fundamentals, understanding useState deeply changes how you think about components. It’s the foundation of every interactive feature you’ll build. #React #JavaScript #FrontendDevelopment #WebDevelopment #ReactJS #useState #Coding #OpenSource #LearnReact

Ever wondered why your React app feels slower than it should, even when nothing seems wrong? You’re probably familiar with how React’s rendering process works. When a component’s state changes, React re-renders that component. And if that component returns other components, all its child components are also re-rendered. You might wonder — what if the state change happens in a top-level component, but none of its child components actually need to update? Would React still re-render all those child components unnecessarily? Yes, it would. React’s reconciliation process helps by comparing the new Virtual DOM with the previous one and updating only what’s changed in the real DOM. This speeds up the updating phase of the UI. However, reconciliation is still limited to the updating phase. It doesn’t improve anything in the rendering phase, meaning React still re-renders all components before it even decides which parts of the DOM to update. That’s the catch — even with reconciliation, React still re-renders all child components, even when their data hasn’t changed. That means extra render cycles and wasted performance. So, how do we stop that? That’s where React.memo() comes in. It tells React to skip re-rendering a component if its props haven’t changed. React can then reuse the previous render result instead of calling the component again. The example in the image below shows this in action. When the button is clicked, the state variable count updates and triggers a re-render. But because we wrapped the child component with React.memo(), React skips re-rendering it since its props remain the same. It’s a simple yet powerful optimization that many developers overlook. Start using React.memo() wherever it makes sense — and make your React apps run faster with minimal effort. #React #JavaScript #WebDevelopment #Frontend #ReactJS #PerformanceOptimization #WebDev #Coding #DeveloperTips

Performance Optimization in React: useMemo & useCallback Simplified Ever noticed your React app slowing down even though you’re just updating small parts of the UI? That’s where React’s optimization hooks come to the rescue — especially useMemo and useCallback. Let’s break it down useMemo Used to memoize (remember) the result of a computation. It helps prevent expensive calculations from running every render. const expensiveValue = useMemo(() => computeHeavyTask(data), [data]); •Runs only when data changes •Without it, computeHeavyTask runs on every render useCallback Used to memoize functions — prevents unnecessary re-creation of functions on each render (which can trigger unwanted re-renders in child components). const handleClick = useCallback(() => { console.log("Clicked!"); }, []); • Returns the same function reference unless dependencies change • Without it, new function → child components re-render unnecessarily Use these only when needed. Overusing them can make your code complex. Ideal when passing callbacks to memoized child components or performing heavy computations. In short: useMemo → Caches values useCallback → Caches functions Both aim to reduce unnecessary re-renders and boost performance. #ReactJS #WebDevelopment #PerformanceOptimization #Frontend #JavaScript #ReactHooks

Treating React state like a regular variable is dangerous. It’s the fastest way to create bugs that make you lose your mind. If your new React state depends on the current state, you have to use the functional form. Everybody knows this… until they don’t. Take the classic toy example: setCount(count + 1) setCount(count + 1) Of course this is a stupid example. Nobody writes code that obviously wrong in real life. But it’s perfect for explaining the core idea: both calls read the same stale count, React batches them, and you don’t get the result you expect. In reality, the mistake hides inside much bigger code. A couple of effects. An event handler or two. Some async calls. A hook that depends on another hook. And suddenly you’re updating state “based on the current state” without even realizing it. That’s when things get tricky: unexpected toggles, missed increments, UI that feels “off by one,” or some weird race condition that only happens when your user clicks fast. The rule stays simple: If the new state is calculated from the old state, use the functional form. Always. setCount(prev => prev + 1) That’s how you avoid all the subtle bugs that only show up when your app gets reactive, event-driven, and real. React state isn’t a variable you overwrite. It’s a timeline of transitions. Once you treat it that way, the weird stuff stops happening. Been there? Tell me. Curious to hear your worst React state surprises. #ReactJS #JavaScript #WebDevelopment #CodingTips #SoftwareEngineering #ReactHooks

React Hooks You Should Be Using (but Probably Aren’t) After working with React for a few years, I’ve realized that most of us only use the “famous five”: useState, useEffect, useContext, useRef, and useMemo. But React gives us so many powerful hooks that can make our code cleaner, faster, and more maintainable. Here are a few underrated ones 1. useCallback Ever had a child component re-render unnecessarily? useCallback helps you memoize functions so they don’t get recreated every render. Perfect for performance optimization. 2. useReducer When state logic gets complex, useReducer brings structure — think of it as a mini Redux inside your component. 3. useLayoutEffect Runs synchronously after DOM mutations — great for reading layout or synchronizing scroll/size before the browser paints. Just don’t overuse it — it blocks painting. 4. useImperativeHandle Used with forwardRef() — it lets you control what gets exposed to parent components through refs. Useful for building reusable, controlled components. 5. useDeferredValue & useTransition (React 18+) These make UI updates feel faster by splitting urgent vs non-urgent renders. Game-changers for improving perceived performance in data-heavy apps. Takeaway: React hooks aren’t just tools — they’re patterns for better mental models. Understanding when and why to use them can make your components simpler, faster, and easier to reason about. Which hook do you think is the most underrated in React? #React #WebDevelopment #Frontend #JavaScript #ReactHooks #NextJS #Performance #SoftwareDevelopment

React Basics – Components, Props & Virtual DOM In React, everything begins with components — the core building blocks of a UI. They make your app modular, reusable, and easy to maintain. Props (short for properties) allow you to pass data between components — just like function parameters. 💡 Example: function Welcome(props) { return <h2>Hello, {props.name}!</h2>; } function App() { return ( <div> <Welcome name="Kishore" /> <Welcome name="Santhiya" /> </div> ); } 🔍 Virtual DOM vs Real DOM The Real DOM updates the entire web page when something changes — which is slow. The Virtual DOM is a lightweight copy of the Real DOM used by React. React updates only the parts that changed, making the app much faster and smoother. 💭 Takeaway: > Components organize your UI, props share data, and the Virtual DOM keeps everything lightning-fast ⚡ #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #VirtualDOM #Props #Components #Coding #LearnReact #DeveloperJourney

⚛️ What Does the DOM Actually Do in React? When we start learning React, we often hear the term DOM — or more commonly, the Virtual DOM. But what does it actually do, and why is it so important? 🧩 What is the DOM? The DOM (Document Object Model) is like a map of your web page. It represents all the elements (like buttons, text, images, etc.) in a tree structure. When your browser loads a page, it builds this DOM so JavaScript can change things — for example, updating text, hiding a button, or changing a color. But there’s one issue — when too many updates happen directly on the DOM, it becomes slow. Every small change causes the browser to redraw the page, which affects performance. ⚡ How React Uses the Virtual DOM React doesn’t change the real DOM directly. Instead, it creates a Virtual DOM — a copy of the real one that lives in memory. Whenever something changes in your app (like user input or state update): React updates the Virtual DOM first. It then compares the new Virtual DOM with the old one (this is called diffing). Finally, it updates only the changed parts in the real DOM. This makes updates faster and the UI smoother. 💡 Why It’s Useful 🚀 Faster updates and rendering 💻 Better performance for complex apps 🧠 Easy for developers — React handles DOM updates automatically 🎨 Smooth user experience without page reloads Example: If you change one letter in a paragraph, React doesn’t rebuild the whole page. The DOM is the structure of your webpage, but the Virtual DOM is React’s smart way of managing it efficiently. It’s one of the main reasons React apps feel so fast, interactive, and dynamic. #ReactJS #JavaScript #WebDevelopment #FrontendDevelopment #Programming #VirtualDOM #WebApps #ReactDevelopers #Coding #SoftwareEngineering #FrontendEngineer #LearnToCode #TechLearning #DeveloperLife #WebPerformance #TechCommunity #CodeNewbie #Innovation #WebDevTips #ReactEcosystem

🧩 How to Debug React Performance Using React DevTools Performance issues in React aren’t always obvious sometimes the UI feels “fine” until you start profiling. That’s where React DevTools comes in ⚙️ Here’s how I use it 👇 1️⃣ Profile Tab Use the Profiler to record re-renders and check which components take the most time to update. 💡 Look for components re-rendering unnecessarily. 2️⃣ Flamegraph View Visualize render time, tall bars = expensive components. 3️⃣ Why Did This Render? Enable this feature to find out what triggered a render, props, state, or context. 4️⃣ Highlight Updates Turn on “Highlight updates” to visually see what re-renders as you interact with your app. 5️⃣ Fix & Retest Once you optimize, rerun the profiler and confirm your changes made a difference. 💡 React DevTools is more than a debugger — it’s your performance microscope. 👉 Have you used the Profiler tab before? What’s your biggest React performance win? #ReactJS #FrontendDevelopment #WebDevelopment #JavaScript #Performance #ReactDevTools #Optimization

⚛️ useReducer in React — The Smarter Way to Handle State 🧩Why useReducer? When your component state becomes too complex for useState, ➡️ it’s time to bring in useReducer! It helps manage multiple state transitions in a clean, predictable way. ⚙️ The Basic Syntax const [state, dispatch] = useReducer(reducer, initialState); 🧠 Think of it as a mini Redux inside React! state → current value dispatch → triggers updates reducer → decides what changes 💡 Example — Counter App function reducer(state, action) { switch (action.type) { case "increment": return { count: state.count + 1 }; case "decrement": return { count: state.count - 1 }; default: return state; } } Now just call 👇 dispatch({ type: "increment" }); Simple and powerful 🔥 🧠When to Use It ✅ Multiple related state values ✅ Complex state logic ✅ Cleaner state management ✅ Easier debugging ⚡useState vs useReducer useState useReducer Simple state Complex logic One value Multiple actions Quick setup More structured 🌍 Pro Tip Combine useReducer + useContext → 💪 Lightweight global state management without Redux! 🚀 Takeaway useReducer makes your React code: ✔️ Organized ✔️ Scalable ✔️ Maintainable When your app grows — this hook keeps your logic under control 🧘♀️ 🙌Wrap-up Have you tried useReducer in your React projects yet? Share your experience below #React #useReducer #WebDevelopment #JavaScript #Frontend #STEMUP