React Infinite Scroll Component v7.0.0 Released

I spent 2 hours debugging my React code today. The problem? I forgot to add a key prop inside .map() 2 hours. Gone. We always check the big things first — API calls, state management, component logic... But the bug is always something embarrassing Here are 3 mistakes I make almost every week — ❌ Forgetting key prop in .map() ❌ Calling setState and expecting instant update ❌ Spending 1 hour on a bug that console.log solves in 2 minutes 3 years of experience and I still do this Tell me your most embarrassing bug in the comments 👇 I promise I won't judge. We have ALL been there. #reactjs #javascript #frontenddeveloper #webdevelopment #coding #100daysofcode #programminghumor

Most developers know var is bad… Yet it’s still showing up in codebases in 2026 😬 Here’s why it keeps breaking things 👇 🔴 var is function-scoped, hoisted, and re-declarable → Leads to silent, hard-to-trace bugs 🟢 const is block-scoped and strict → Fails fast, catches mistakes early, keeps your code predictable 💡 The rule is simple: → const by default — always → let when reassignment is needed → var — never again ⚡ Quick 5-second fix: Add "no-var": "error" to your ESLint config and enforce it across your team 👀 Still seeing var in your codebase? Drop a 😅 — you’re definitely not alone ♻️ Repost this to save your team hours of debugging 👉 Follow Mohd Sharfuddin Khan for daily JavaScript tips that actually level up your coding #JavaScript #WebDevelopment #Frontend #CodingTips #CleanCode #Developers #ESLint #JSDaily #WebDevelopment #FrontendDeveloper #100DaysOfCode #CodeTips #LearnToCode #ProgrammingTips #TechCommunity #DevLife

#Day25 Today’s focus was on debugging. Not avoiding errors, but understanding them. Bugs can be frustrating, I know that but now I see them as clues. Things that helped today: => Read the error message carefully => Add logs at key points => Break the problem into smaller parts => Don’t rush — trace the flow I also noticed something: Most bugs aren’t “big problems”, they’re small assumptions that turned out to be wrong. A wrong path. An unexpected value. A step that didn’t run. Debugging forces you to slow down and actually see what your code is doing. #JavaScript #NodeJS #BackendDevelopment #Debugging #LearningToCode #M4ACELearningChallenge

Quick experiment. Pick a dependency in your project. Now ask yourself: If I remove this, what breaks? Most of us do not know without trying. So we avoid touching anything. And over time, projects accumulate dependencies that may not even be needed anymore. Not because developers are careless. Because the feedback loop is expensive. This is exactly the problem I’ve been working on with Depsly. Simulate changes. Understand impact. Then act. pip install depsly depsly analyze #opensource #devtools #javascript #nodejs #softwareengineering #webdev

Day 4 of 30 Days of TypeScript 🚀 Today’s topic: any vs unknown A lot of developers use any thinking it gives flexibility… But in reality, it removes the biggest advantage of TypeScript — type safety. Here’s the truth: 🔴 any Disables type checking Allows anything (even wrong code) Can lead to runtime bugs 🟢 unknown Forces you to validate data Keeps your code safe Encourages better patterns Example 👇 let data: unknown = "hello"; if (typeof data === "string") { console.log(data.toUpperCase()); // ✅ safe } 👉 Rule of thumb: If you don’t know the type yet, use unknown — not any. Because good developers don’t just make code work… They make it reliable. #TypeScript #WebDevelopment #JavaScript #Frontend #CleanCode #100DaysOfCode

🔥 JavaScript Devs — Why “Works on My Machine” Still Happens Hey devs 👋 You tested locally. Everything perfect. Then production says: 💥 Nope. 👉 Common causes: Different Node versions Missing env variables Browser differences Hidden local cache OS-specific behavior 💡 What pros do: ✔ Use Docker ✔ Lock versions ✔ CI pipelines ✔ Test production-like environments ⚡ Senior insight: “If local and production differ… bugs are guaranteed.” 👉 Consistency beats confidence. How do you avoid environment bugs? #javascript #webdevelopment #devops #frontenddeveloper #backenddeveloper #softwareengineering #docker #codingtips #cleanCode #productionready #success

We migrated 200,000 lines of production JavaScript to strict TypeScript — with zero downtime, over 4 months, while shipping features every sprint. Not a weekend hackathon. A systematic 5-phase strategy on a 6-year-old Node.js monolith serving 50K daily active users. The results after 4 months: → Type-related bugs: -85% → New developer onboarding time: -50% → CI catch rate: ~40% → ~95% → Refactoring confidence: 3.2/10 → 8.1/10 The killer insight? strictNullChecks alone found 3 production bugs we didn't know about. One was a race condition hiding for months. I wrote the full playbook — from the tsconfig.json setup to the CI guardrails that prevent regression. Read the full case study: https://lnkd.in/dPD5spCJ What's your biggest fear about migrating a legacy JS codebase to TypeScript? #TypeScript #JavaScript #Migration #SoftwareArchitecture #WebDevelopment #NodeJS #CleanArchitecture #DeveloperProductivity

💻 5 React mistakes I stopped making (and it improved my code a lot) When I started with React, I used to write code that worked… But not code that was clean, scalable, and maintainable. Here are 5 mistakes I fixed: ❌ 1. Writing everything in one component 👉 Now I break UI into small reusable components ❌ 2. Ignoring proper state management 👉 Learned when to use useState vs useEffect vs lifting state ❌ 3. Not handling performance 👉 Started using memoization (useMemo, useCallback) ❌ 4. Poor folder structure 👉 Now I follow a clean project structure ❌ 5. Debugging randomly 👉 Now I debug step-by-step with proper logs Small changes… but huge difference in code quality 🚀 Still learning every day 👨💻 Which mistake did you make the most? 😅 #ReactJS #FrontendDevelopment #JavaScript #CleanCode #WebDevelopment #SoftwareEngineer

Most production bugs I’ve seen around environment variables aren’t caused by missing values. They’re caused by misunderstanding what environment variables actually are. A few things that have burned teams I know: - Environment variables are an OS primitive. Every process gets a flat key-value copy of its parent’s environment. A copy, not a reference. What your child process changes, your parent never sees. - Your .env file does nothing on its own. Something has to read it. And most tools, including dotenv, will NOT overwrite a variable that already exists. So if your shell profile already exports DATABASE_URL, your .env is silently ignored. This is probably the most common “works on my machine” culprit. - Docker starts with a clean slate. It does not inherit your shell environment. If you’re not explicitly passing variables with -e or –env-file, the container doesn’t know they exist. - React’s process.env is not real runtime config. The bundler replaces every reference with a literal string at build time. That value is now hardcoded in the JavaScript your users download. If you put a secret in REACT_APP_anything or NEXT_PUBLIC_anything, it is not a secret anymore. - Build time and runtime are fundamentally different. A frontend bundle bakes values in at build time. An Express server reads the actual process environment when it starts. You can change a backend variable and restart. You cannot do that with a bundled frontend without rebuilding. Deleted a committed secret in the next commit? The key is still in git history. git show will find it. The only fix is to rotate the credential. The mental model that fixes most of this: secrets always runtime, never build time, never committed to source code. #SoftwareEngineering #DevOps #WebDevelopment #BackendDevelopment #JavaScript #Docker #NodeJS #EngineeringLeadership

Debugging a React + TypeScript deployment was a rollercoaster today. Here is what I learned: Project Overview: Ajaia Docs is a modern, responsive documentation platform built with React, TypeScript, and Vite, designed with a clean UI and a scalable monorepo architecture where users can share and edit documents conveniently. I just finished submitting my latest project, Ajaia Docs (a documentation platform built with React, TypeScript, and Vite). Getting it to work locally was smooth, but pushing it to production was a completely different beast. I hit a wall with deployment, and it taught me some valuable lessons about real-world architecture: 1. Dev vs. Prod Environments: My app used a proxy to connect the frontend to a backend API on localhost:3001. I learned the hard way that static hosts (like Vercel/Netlify) don't run backend servers automatically! 2. Monorepo Structures: Having a /client and /server folder means your deployment platform needs exact instructions on where to look (Root Directory settings) and where to put the build. 3. TypeScript is strict for a reason: I spent an hour troubleshooting deployment errors, only to find a tiny type mismatch (user_id vs userId) in an API route. TS caught what would have been a silent runtime bug. Deployment isn't always just pushing a button. It requires understanding how your code is actually bundled and served to the browser. Huge shoutout to the dev community for the resources that helped me untangle this. Repo here: https://lnkd.in/guTYWCwr #ReactJS #TypeScript #Vite #WebDevelopment #SoftwareEngineering #100DaysOfCode #TechJourney