Common React Mistakes to Avoid for Better Performance

𝐈𝐬 𝐑𝐞𝐚𝐜𝐭 𝐚 𝐟𝐫𝐚𝐦𝐞𝐰𝐨𝐫𝐤 𝐨𝐫 𝐚 𝐥𝐢𝐛𝐫𝐚𝐫𝐲? I used to genuinely not know the answer to this. I kept hearing both and just... went along with it. Until I actually looked it up. First stop - the official React docs at https://react.dev. Right there on the homepage it calls itself "the library for web and native user interfaces." Then I checked MDN https://lnkd.in/gTP_zAW4, which is basically the bible for web developers. Same answer - React is a library, not a framework. They even say it outright: "React is not a framework." So what's the actual difference? React only handles the UI layer. That's it. No routing built in, no state management system, nothing like that. You pull in other tools for those things yourself. A framework would give you all of that out of the box - think structure vs. flexibility. That's why React feels like a framework when you're using it in a big project. But technically, it's not. Honestly, once that clicked, the way I think about frontend tools completely changed. I stopped treating React like it was supposed to do everything and started understanding why we add libraries like React Router or Zustand alongside it. Sometimes the confusion isn't about how hard something is - it's just that nobody explained the basics clearly enough from the start. #React #FrontendDevelopment #JavaScript #WebDevelopment #LearningInPublic

⚡ A Simple React Optimization: Using React.memo While building React applications, one thing that can impact performance is unnecessary component re-renders. Sometimes a component re-renders even when its props haven’t changed. This is where React.memo can help. 🔹 What is React.memo? React.memo is a higher-order component that memoizes a component. It prevents re-rendering if the component’s props remain the same. Example 👇 const UserCard = React.memo(({ name }) => { return {name}; }); Now UserCard will only re-render when the name prop actually changes. 🔹 When should you use it? ✅ Components that receive the same props frequently ✅ Pure UI components ✅ Components inside large lists 🔹 When NOT to use it ⚠️ Very small components ⚠️ Components that always receive new props ⚠️ Without measuring performance impact 💡 One thing I’ve learned while working with React: Optimization should always be intentional and measured. Tools like React DevTools Profiler can help identify components that are re-rendering unnecessarily. Curious to hear from other developers 👇 Do you regularly use React.memo, or do you optimize only when performance issues appear? #reactjs #frontenddevelopment #javascript #webdevelopment #reactperformance #softwareengineering #coding

Why do simple React UIs sometimes become hard to maintain? In my experience, it’s usually not because of the components — it’s because of unclear UI states when dealing with APIs. Recently while working on a feature, the UI logic started getting messy even though the layout was simple. The real issue was that the component wasn’t explicitly handling different API states. We restructured the flow around four clear states: • Loading – when the API request is in progress • Error – when the request fails • Empty – when the API returns no results • Success – when valid data is available Once these states were handled clearly, the component logic became much simpler and the UI behavior became far more predictable. Small pattern, but it makes a big difference in API-driven React applications. Curious how others structure UI states in their React projects. #reactjs #frontendengineering #javascript #webdevelopment #uidevelopment

What Runs First in React? Most React developers know what useEffect, useMemo, and useCallback do individually. Far fewer know the exact order they execute in. And that gap causes bugs that are surprisingly difficult to trace. Here is the definitive execution order on first mount: -> Step 1: Rendering JSX React runs the function body of your component first. JSX is evaluated. console.log inside the return runs here. This is the render phase. -> Step 2: useMemo runs during render useMemo executes synchronously during the render phase, not after it. If you have an expensive computation wrapped in useMemo, it runs as part of building the component output. This is why useMemo can be used to compute values that are needed in the JSX itself. -> Step 3: useEffect runs after render After the component has rendered and the DOM has been updated, useEffect fires. It is intentionally deferred. This is where API calls, subscriptions, and side effects belong because they should not block the render. -> useCallback is different from all of them useCallback does not run during mounting. It stores a function reference. That function only executes when it is explicitly called. In the example on the right, increment only logs when you actually call increment(). The final order: Rendering JSX, then useMemo, then useEffect. Why this matters in practice: If you expect useEffect to run before useMemo, your state update will not be available when useMemo computes. If you expect useCallback to run automatically, your side effect will never fire. Getting the order wrong means working with stale data and writing code that behaves differently than you intended. Understanding execution order is not academic. It is the difference between components that behave predictably and ones that produce subtle timing bugs you spend hours debugging. Did you know the exact execution order before seeing this or did it surprise you? #React #ReactHooks #FrontendDevelopment #JavaScript #WebDevelopment #Developers

I struggled with this React concept more than I expected… 👇 👉 Why are my API calls running twice? ⚙️ What you’ll notice You open your network tab and suddenly see this: api/me → called twice api/roles → called twice api/permissions → called twice Just like in the screenshot 👇 Same request, duplicated… again and again. ⚙️ What’s actually happening In React (development mode), if your app is wrapped in Strict Mode, React will run effects twice on purpose. useEffect(() => { fetch("/api/users") .then(res => res.json()) .then(setUsers); }, []); Even though it looks like it should run once… it doesn’t (in dev). 🧠 What’s going on under the hood React basically does a quick cycle: mount → unmount → remount Why? To catch hidden side effects To check if cleanup is handled properly To make sure your logic doesn’t break on re-renders So if your API call runs twice, React is just making sure your code can handle it. 💡 The important part This only happens in development Production behaves normally (runs once) Your side effects should be safe to run multiple times 🚀 Final thought If your network tab looks “noisy” like the screenshot, it’s not React being broken — it’s React being careful. And once you understand this, debugging becomes a lot less confusing. #React #Frontend #JavaScript #WebDevelopment #ReactJS #SoftwareEngineering

🔄 Understanding useReducer in React When managing state in React, most developers start with useState. But as applications grow, state logic can become complex. That’s where useReducer becomes very useful. Think of useReducer as a more structured way to manage state, especially when multiple state changes depend on specific actions. 📌 What is useReducer? useReducer is a React Hook that lets you manage state using a reducer function. It works similarly to how reducers work in Redux. It takes two main things: 1️⃣ A reducer function 2️⃣ An initial state const [state, dispatch] = useReducer(reducer, initialState); state → the current state dispatch → a function used to send actions reducer → decides how state should change 📌 Example const initialState = { count: 0 }; function reducer(state, action) { switch (action.type) { case "increment": return { count: state.count + 1 }; case "decrement": return { count: state.count - 1 }; default: throw new Error("Unknown action"); } } function Counter() { const [state, dispatch] = useReducer(reducer, initialState); return ( <> <p>{state.count}</p> <button onClick={() => dispatch({ type: "increment" })}> Increment </button> <button onClick={() => dispatch({ type: "decrement" })}> Decrement </button> </> ); } Here, instead of directly updating state like setCount, we dispatch actions and the reducer decides how the state should change. 📌 When Should You Use useReducer? ✅ When state logic is complex ✅ When multiple state updates depend on each other ✅ When managing objects or multiple state values ✅ When you want predictable state transitions 💡 Key Insight useReducer separates state logic from UI logic, making your components easier to read, test, and maintain. As React applications grow, this pattern helps keep your state management clean and scalable. 💬 Are you using **useState or useReducer more often in your React projects? #React #FrontendDevelopment #JavaScript #WebDevelopment #ReactHooks #LearningInPublic

🚀 Understanding Functional vs Class Components in React — Simplified! In React, everything revolves around components. But there are two types: 👉 Functional Components 👉 Class Components So… which one should you use? 💡 What are Functional Components? 👉 Simple JavaScript functions that return JSX function Greeting() { return <h1>Hello, React!</h1>; } ✅ Cleaner syntax ✅ Easier to read ✅ Uses Hooks (useState, useEffect) ✅ Preferred in modern React 💡 What are Class Components? 👉 ES6 classes that extend React.Component class Greeting extends React.Component { render() { return <h1>Hello, React!</h1>; } } 👉 Uses lifecycle methods instead of hooks ⚙️ Key Differences 🔹 Functional: Uses Hooks Less boilerplate Easier to maintain 🔹 Class: Uses lifecycle methods More complex syntax Harder to manage state 🧠 Real-world use cases ✔ Functional Components: Modern applications Scalable projects Cleaner architecture ✔ Class Components: Legacy codebases Older React apps 🔥 Best Practices (Most developers miss this!) ✅ Prefer functional components in new projects ✅ Use hooks instead of lifecycle methods ✅ Keep components small and reusable ❌ Don’t mix class and functional patterns unnecessarily ⚠️ Common Mistake 👉 Overcomplicating simple components with classes // ❌ Overkill class Button extends React.Component { render() { return <button>Click</button>; } } 👉 Use functional instead 💬 Pro Insight React today is built around: 👉 Functions + Hooks, not classes 📌 Save this post & follow for more deep frontend insights! 📅 Day 7/100 #ReactJS #FrontendDevelopment #JavaScript #ReactHooks #WebDevelopment #SoftwareEngineering #100DaysOfCode 🚀

Ever looked at a React or Next.js project and thought, "Why do I need both package.json AND package-lock.json? Don't they do the exact same thing?" 🤔 It’s a completely normal question, and it's easy to assume they are redundant. But here is the reality check: they don't actually contain the same information. While package.json holds your custom commands (like npm run dev), your lock file strictly handles exact dependency trees. 🌲 They are a dynamic duo, not duplicates. Here is the straightforward breakdown of why your project needs both to survive the modern web matrix: 📄 The Blueprint: package.json 👨💻 Human-Readable: This is your app's manifest. You write, edit, and maintain this file. 🌊 Flexible Versions: It lists your top-level dependencies using version ranges (e.g., "react": "^18.2.0"). The caret (^) means "give me version 18.2.0 or any newer minor update that doesn't break things." 🎛️ Project Control Center: It holds your project metadata, author details, and your custom execution scripts. 🔒 The Snapshot: package-lock.json 🤖 Machine-Generated: You should never manually edit this file. Node Package Manager (npm) creates and updates it automatically. 🎯 Exact Versions: It completely ignores flexible ranges. It records the exact version of every single dependency installed, plus the dependencies of those dependencies (the entire tree). 🛡️ Guaranteed Consistency: It is the cure for the "it works on my machine" excuse. It ensures that when a teammate clones the repo, or when your code goes to a production server, the exact same underlying code is installed every single time. Without the lock file, a random update to a deep sub-dependency could completely break your app overnight—even if you didn't touch a single line of code. 💥 💡 The TL;DR: package.json requests what you want; package-lock.json guarantees what you get. Tags: #WebDevelopment #ReactJS #NextJS #NPM #FrontendDevelopment #JavaScript #TypeScript #MERNStack #10FreeProjectChallenge #CodingJourney #SoftwareEngineering

I recently worked on a project for a client where I had to convert an existing website that was built with HTML, CSS, and JavaScript into React using TypeScript. At first, I thought it would be a simple migration. But after checking the code, I saw that it was more than just moving files. I had to break the project into components, add TypeScript types, and change some parts of the structure so that the app could be easier to manage and scale in the future. While the process took more effort than expected, it was also a great reminder of why modern tools matter. Moving to React + TypeScript not only improves maintainability but also makes future backend integration and scaling much easier. Projects like this help me improve my skills and build better websites. If you have done something similar, you can share your experience in the comments. #WebDevelopment #React #TypeScript #FrontendDevelopment #SoftwareEngineering

💡 React Tip: Why Functional Components Are the Standard Today When I started working with React, class components were widely used. But over time, functional components have become the preferred approach — especially with the introduction of React Hooks. Here are a few reasons why developers prefer functional components today: ✅ Cleaner and simpler code – Less boilerplate compared to class components ✅ Hooks support – Hooks like useState, useEffect, and useMemo make state and lifecycle management easier ✅ Better readability – Logic can be grouped by functionality instead of lifecycle methods ✅ Improved performance optimization – Tools like React.memo and hooks make optimization easier Example: function Counter() { const [count, setCount] = React.useState(0); return ( <button onClick={() => setCount(count + 1)}> Count: {count} </button> ); } Functional components combined with Hooks make React development more scalable, maintainable, and easier to reason about. 📌 Curious to know from other developers: Do you still use class components in production projects, or have you fully moved to functional components? #ReactJS #FrontendDevelopment #JavaScript #WebDevelopment #ReactHooks