Matheus Wilberstaedt’s Post

frameworks and libraries is all about syntax, the real deal is knowing what powers them... useEffect and useState are dangerous syntax to someone who doesn't understand how window loaded and DomContent event listeners work in pure javaScript... Axios is great but if you dont know how the fetch API works, the you would struggle to undertstand how the browser handles http errors... Knowing the fundamentals isn't about going back to the stone age, its what you need to build with confidence. #reactjs #frontend #javaScript

POV: You install one “small” npm package. Your project: 😌 Your node_modules: 🔥🔥🔥 We don’t install dependencies in JavaScript… We adopt their entire family tree. And somehow we still say, “It’s lightweight.” #JavaScript #ReactJS #NodeJS #WebDevelopment #Frontend #ProgrammingHumor

In React, a Hook is just a JavaScript object. Each Hook stores: the state value a queue of updates and a reference to the next Hook Internally it looks like this: { memoizedState: state, queue: updates, next: nextHook } React stores Hooks as a linked list attached to the component's Fiber node. Fiber → Hook → Hook → Hook → null This is why Hooks must always be called in the same order. React reads them one by one during every render. When you call setState, React adds the update to the Hook's queue, and processes it during the next render. Hooks are not magic. They are simple objects connected together. Understanding this helps explain many React behaviors. #reactjs #javascript #webdevelopment

Closures finally clicked for me — and most of my React bugs suddenly made sense. Key realization: Closures capture variables, not values. Every React render creates a new closure. That explains: stale state in setTimeout useEffect([]) freezing values why functional updates work why useRef fixes async bugs Once you see React through the lens of lexical environments, debugging stops being guesswork and becomes logic. Actively leveling up my JavaScript fundamentals to operate at a senior frontend level. 🚀 #JavaScript #Closures #ReactJS #FrontendEngineering #LearningInPublic

React Performance isn’t about adding hooks everywhere. It’s about adding them where they matter. Most applications suffer from unnecessary re-renders and unstable references. Two small hooks. Massive impact: 1. useCallback → Stabilize function references 2. useMemo → Avoid expensive recalculations But misuse them, and you just add complexity with zero gains #ReactJS #NextJS #FrontendDevelopment #WebPerformance #JavaScript #SoftwareEngineering #ReactPerformance #Optimization #CleanCode #TechLeadership #UIDevelopment #ProgrammingTips

🚀 30 Days of JavaScript Tricky Questions – Day 1 Let’s start with async / await + event loop 🧠 async function foo() { console.log('A'); setTimeout(() => console.log('B'), 0); await Promise.resolve(); console.log('C'); } foo(); console.log('D'); ❓ What will be the output and why? 💬 Drop your answer in the comments #JavaScript #JSInterview #AsyncJavaScript #FrontendDeveloper #WebDevelopment #30DaysOfJavaScript

💡 Small Lesson I Learned While Building React Applications While working on projects, I realized something important: Always try to handle things on the frontend before making unnecessary API calls. For example, if data is already fetched from the API, you can implement features like searching, filtering, and sorting directly on the frontend using JavaScript instead of calling the API again and again. Benefits: ✅ Faster user experience ✅ Reduced server load ✅ Cleaner architecture Sometimes the best optimization is simply using the data you already have. What’s a small development lesson you learned recently? 👇 #webdevelopment #reactjs #javascript #frontenddevelopment #learninginpublic

React doesn't update the entire page. It's way smarter than that. Here's what actually happens behind the scenes in 6 simple steps: 📋 Virtual DOM — a lightweight JS copy of the real DOM 🔍 Diffing — comparing old vs new to spot changes 🔄 Reconciliation — the full compare-and-update cycle ✏️ JSX — looks like HTML, but it's JavaScript 🔧 Babel — translates JSX into plain JS before the browser sees it 🚀 The Flow — JSX → Babel → Virtual DOM → Diff → Real DOM Save this. The next part covers Components, Props & State. ♻️ Repost to help someone learning React. #React #VirtualDOM #JavaScript #WebDevelopment #Frontend #LearnToCode

Why Array Comparison in React State Is Tricky? If you’ve ever updated an array in React and your component didn’t re-render, you’re not alone. The reason? React compares state by reference, not by value. So if you modify the same array instead of creating a new one, React thinks nothing changed — even if the data inside it did. Never mutate state directly. Always create a new array or object when updating state. #ReactJS #JavaScript #FrontendDevelopment #WebDevelopment