React Mistakes to Avoid: Simplify with Core Concepts

🚀 30 Days — 30 Coding Mistakes Beginners Make Day 3/30 I changed the state… but React didn’t update the UI 😐 The mistake: user.name = "John" setUser(user) I directly modified the state object. React compares references, not deep values. Since the object reference stayed the same, React thought nothing changed. Correct way 👇 setUser({ ...user, name: "John" }) Create a NEW object instead of mutating the old one. In React: Mutating state = invisible bugs Immutable state = predictable UI This one mistake causes many “React is not working” moments for beginners. Day 4 tomorrow 👀 #30DaysOfCode #reactjs #javascript #frontend #webdevelopment #codeinuse

Learning React made me realize something — frontend isn’t about “changing elements.” It’s about controlling state and thinking in systems. Once that clicked, everything started making sense. Still early in the journey, but the foundation is getting stronger every day. Next stop: advanced hooks and performance optimization. Building > consuming. #ReactJS #JavaScript #FrontendDeveloper #WebDevelopment #CodingJourney #LearnInPublic #FullStackPath

🚀 30 Days — 30 Coding Mistakes Beginners Make Day 9/30 I built a form in React… and used: document.getElementById("name").value It worked. But later validation broke, reset didn’t work, and UI went out of sync 😐 Because React was not controlling the input. The DOM was. Correct way 👇 Use controlled input with state. <input value={name} onChange={e => setName(e.target.value)} /> In React: State should control UI not the DOM. This is why React forms become predictable and easier to debug. Day 10 tomorrow 👀 #30DaysOfCode #reactjs #javascript #frontend #webdevelopment #codeinuse

🚀 30 Days — 30 Coding Mistakes Beginners Make Day 7/30 I typed inside an input… clicked “Add new item”… and the text moved to another field 😳 The bug? key={index} I used array index as React key. React does not track elements. React tracks keys. When list order changes, React reuses DOM nodes, so your input becomes a different item. Fix 👇 key={item.id} Stable key = stable UI. React warnings are not decoration… they are future bugs. Day 8 tomorrow 👀 #30DaysOfCode #reactjs #javascript #frontend #webdevelopment #codeinuse

🚀 30 Days — 30 Coding Mistakes Beginners Make Day 16/30 My component received a new userId… but UI still showed the old user 😐 The reason? I wrote: useEffect(() => { fetchUser(userId) }, []) Empty dependency array means: run only once on mount. So when userId changed, React never fetched new data. Fix 👇 useEffect(() => { fetchUser(userId) }, [userId]) Dependencies tell React WHEN to re-run the effect. Missing dependency = stale UI data. Day 17 tomorrow 👀 #30DaysOfCode #reactjs #javascript #frontend #webdevelopment #codeinuse

I was literally stuck while trying to understand the Context API in React. I explored many tutorials, but the concept still wasn’t completely clear. Finally, I came across the React playlist by @VinodBahadurThapa on the YouTube channel Thapa Technical, and it completely changed my understanding. The explanation of Context API was simple, practical, and beginner-friendly. Now, it feels smooth and much more logical to implement in real projects. Grateful for such quality content that genuinely helps developers grow. 🙌 If you're struggling with React concepts, I highly recommend checking out the playlist. #ReactJS #ContextAPI #FrontendDevelopment #JavaScript #LearningJourney #WebDevelopment

🚀 30 Days — 30 Coding Mistakes Beginners Make Day 18/30 I clicked “Add Item”… nothing happened 😐 No error. No warning. Button worked. My code: items.push("New Task") setItems(items) The array DID change. But React didn’t update UI. Why? Because React doesn’t check contents. React checks references. Same array reference = React thinks nothing changed. Fix 👇 setItems([...items, "New Task"]) Create a NEW array instead of modifying the old one. This single mistake causes many: “React state not updating” moments. Save this — you will hit this bug in a real project. #30DaysOfCode #reactjs #javascript #frontend #codeinuse

🚀 30 Days — 30 React Mistakes Beginners Make 📅 Day 4/30 ❌ Mistake: Making Input Controlled Without onChange I wrote this 👇 <input value={name} /> Input stopped typing 😐 💡 Why? When you pass value, React controls the input. But without onChange, it becomes read-only. React says: “If I control it, you must update it.” ✅ Correct Way <input value={name} onChange={(e) => setName(e.target.value)} /> 🎯 Lesson If you use value, always handle onChange. Controlled component = state-driven input. #ReactJS #JavaScript #FrontendDev #WebDevelopment #CodingProblems #ReactHooks #DevTips #ProgrammingLife #TechLearning #UIEngineering

🚀 30 Days — 30 Coding Mistakes Beginners Make Day 17/30 I wrote an API call inside `useEffect`… and React showed a warning 😐 useEffect(async () => { const res = await fetch("/api/users") }, []) The mistake: `useEffect` should NOT be async. React expects the effect to return either: nothing, or a cleanup function. But async always returns a Promise. Fix 👇 Create an async function INSIDE the effect and call it. useEffect(() => { async function fetchUsers() { ... } fetchUsers() }, []) Small change. Correct lifecycle behavior. Day 18 tomorrow 👀 #30DaysOfCode #reactjs #javascript #frontend #webdevelopment

⚛️ Day 4 of Learning React.js Today I learned about Props in React.js. I understood that props (short for properties) are used to pass data from one component to another. This makes components more dynamic and reusable instead of hardcoding values. What I learned today: What are props in React How to pass data from parent to child component Using props inside functional components Making components reusable with different data Now I can create components that display different content based on the data passed to them. It’s starting to feel more structured and powerful compared to plain JavaScript. Step by step learning and improving every day 🚀 #ReactJS #FrontendDevelopment #JavaScript #WebDeveloper #LearningJourney #StudentDeveloper #Consistency