JavaScript Function Comparison Hurts UI Performance

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

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

React confused me today… for a simple .push() 😅 I was updating an array in state and did this: items.push(newItem) setItems(items) Pretty normal JavaScript, right? But the UI didn’t update. That’s where I got stuck. Then I realized what was actually happening. Arrays in JavaScript are stored by reference. So .push() doesn’t create a new array — it just modifies the existing one. React compared the old state and new state… and saw the same reference. So it thought: “Nothing changed.” 💡 The way I understand it now: Using .push() → same box 📦 Using spread → new box 📦✨ React only reacts when the box changes, not just what’s inside it. So the correct way: setItems(prevItems => [...prevItems, newItem]) Small thing, but it cleared up a lot for me. One more step forward 🚀 #ReactJS #JavaScript #Frontend #LearningInPublic

Why does React say: "Don't call hooks conditionally"? 🤔 Let’s break it down simply. React doesn’t track hooks by name. It tracks them by order. Every render, React just walks through hooks like this: 1st hook → 2nd hook → 3rd hook That’s it. No labels. No IDs. Just position. Now imagine this 👇 if (condition) { useEffect(() => { // do something }); } 👉 First render: Hook1 → Hook2 → Hook3 👉 Next render (condition = false): Hook1 → Hook3 Now React gets confused 😵 It expects Hook2… but suddenly sees Hook3. This breaks the internal hook mapping — and boom 💥 unexpected bugs or crashes. 👉 The rule exists because hooks must run in the same order on every render. That’s why: ❌ No hooks inside conditions ❌ No hooks inside loops ❌ No hooks inside nested functions 👉 Always call hooks at the top level. Once you understand this, React hooks feel much less “magical” and more predictable. #ReactJS #JavaScript #FrontendDevelopment #WebDevelopment #LearnInPublic

🎯 useEffect vs useLayoutEffect: finally made it clear While learning React hooks, I was confused between useEffect and useLayoutEffect. This visual helped me understand the real difference 👇 👉 useLayoutEffect 1. Runs synchronously 2. Executes before the browser paints the UI 3. Useful when you need to measure or update the DOM before it becomes visible 👉 useEffect 1. Runs asynchronously 2. Executes after the UI is painted 3. Best for API calls, timers, subscriptions, etc. 💡 Key takeaway: 1. useLayoutEffect → blocks paint (use carefully) 2. useEffect → doesn’t block UI (preferred in most cases) Also learned how cleanup (destroy/unmount) works to avoid memory leaks especially with intervals and API calls. Small concepts like this make a big difference in writing better React code #ReactJS #WebDevelopment #Frontend #JavaScript #LearningInPublic #ReactHooks

⚛️🚀Building reusable components is one of the best ways to write cleaner, scalable React code. In my latest blog, I break down how I created a dynamic, beginner‑friendly button component that adapts based on props—no more repeating the same markup. From conditional rendering to flexible class handling, this approach keeps your UI consistent and efficient. A great starting point for anyone improving their React workflow! https://lnkd.in/djJWMbZj #ReactJS #WebDevelopment #FrontendDev #ReusableComponents #JavaScript #CleanCode #ReactTips #TailwindCSS #CodingJourney #SoftwareEngineering

Tailwind just shipped vanilla JavaScript support for their UI components, and I'm genuinely surprised it took this long. Not because it's hard to build — it's not. But because the entire ecosystem spent the last five years assuming everyone was either a React or Vue shop. The quiet majority of projects out there? Plain HTML with a sprinkle of vanilla JS. Still works. Still ships. Still makes money. I've been using Tailwind since the early days, and watching it evolve from "utility-first CSS that nobody asked for" to "the default choice for 70% of new projects" has been fascinating. But it always felt slightly patronising — like the framework was saying, "If you're not using a JavaScript framework, here's your consolation prize." Now? Every Tailwind Plus component works standalone. Dropdowns, dialogs, command palettes. All functional. All accessible. All without needing React or Vue bolted on. It's a small shift, but it matters. It means teams can use Tailwind Plus on legacy projects without forcing a framework migration. It means junior developers learning web fundamentals can actually build something interactive without drinking the component framework Kool-Aid first. The boring tooling wins again. And I'm here for it. https://lnkd.in/dN-ehMg6

💡 #JavaScript Global vs Local Variables (Simple Explanation) If you're learning JavaScript, understanding variable scope is a must 👇 🔹 Global Variables Declared outside any function Accessible from anywhere in your code Can be used across multiple functions Example: var name = "Avi"; function greet() { console.log(name); // Accessible here } 🔹 Local Variables Declared inside a function or block Accessible only within that function/block Helps avoid unwanted changes from outside Example: function greet() { var message = "Hello"; console.log(message); // Works here } console.log(message); // ❌ Error ⚡ Key Difference Global = accessible everywhere Local = accessible only inside its scope 👉 Tip: Prefer #local variables to keep your code clean and avoid bugs. Use #global where multiple parts of your app need the same value. #frontend #js #javascript

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

Why is your useEffect sitting idle even after you've updated the variable? Look at this snippet. If you’re coming from a Vanilla JS background, count = count + 1 looks perfectly fine. But in React? This code is technically "dead." Why this won't work: * Mutation != Re-render: You are updating a local let variable. React has no "spy" watching your local variables. Unless you call a state setter (like setCount), React doesn't know it needs to re-render the component. * The Lifecycle Gap: useEffect only checks its dependency array ([count]) when the component re-renders. Since the button click doesn't trigger a render, React thinks nothing has changed. * The "Reset" Trap: Even if the component did re-render for some other reason, the first line let count = 0; would run again, resetting your value back to zero every single time. The Fix? Stop treating React like a standard script. Use useState. When you use const [count, setCount] = useState(0), you’re telling React: "Hey, keep an eye on this value. If I change it via setCount, please refresh the UI and check my Effects." Pro-tip: In React, if you want the UI to "react," you have to use the Hook. Simple as that. #ReactJS #WebDevelopment #Frontend #CodingTips #IndiaDevs #Javascript