Understanding JavaScript Event Loop with Microtasks and Macros

JavaScript Notes From Basics to Interview-Ready Concepts These JavaScript notes cover everything from core fundamentals to advanced concepts frequently asked in interviews. Topics include execution context, scope, hoisting, closures, async JavaScript, promises, event loop, and performance tips. Designed for developers who want clarity, depth, and practical understanding not just theory. #JavaScript #FrontendDevelopment #WebDevelopment #JSBasics #InterviewPreparation #SoftwareEngineering #ReactJS #FullStackDeveloper

“JavaScript interviews don’t test how much you know — they test how deeply you understand.” Closures, async/await, prototype chain — these aren’t just buzzwords. They’re the difference between writing code that works and code that scales. 🚀 If you master the fundamentals, frameworks will follow naturally. 💡 Save this thought: Strong roots = Strong developer. #JavaScript #WebDevelopment #FrontendEngineer #CodingInterviews #CleanCode #AsyncJS #Closures #DeveloperGrowth #TechCommunity #SoftwareEngineering #LinkedInCreators 

𝗝𝗮𝘃𝗮𝗦𝗰𝗿𝗶𝗽𝘁 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝗤𝘂𝗲𝘀𝘁𝗶𝗼𝗻𝘀 — 𝗖𝗿𝗮𝗰𝗸 𝗬𝗼𝘂𝗿 𝗡𝗲𝘅𝘁 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 Preparing for a JavaScript interview? Mastering core concepts is the key to standing out as a frontend or full-stack developer. 💡 These interview questions cover: ✅ Closures and scope ✅ Hoisting and execution context ✅ Event loop and asynchronous JavaScript ✅ Promises and async/await ✅ "this" keyword and binding ✅ Prototypes and inheritance ✅ ES6+ features ✅ DOM and event handling ✅ Performance optimization Perfect for beginners, experienced developers, and anyone preparing for technical interviews. 🚀 Strengthen your fundamentals and boost your confidence to crack top tech interviews! #JavaScript #JavaScriptInterview #FrontendDeveloper #WebDevelopment #CodingInterview #Programming #SoftwareDeveloper #TechInterview #DeveloperTips #LearnJavaScript

🚀 React 19 in interviews (explained the way interviewers like it) If you understand the why, not just the what, you’re already ahead 👇 ✅ React Server Components (RSC) 📌 Example: Product list rendered on the server, only cart buttons on the client ❓ Why RSC? 👉 Smaller JS bundle + faster initial load ✅ Actions API 📌 Example: Login form without onSubmit handlers ❓ What problem does it solve? 👉 Cleaner form handling & simpler server mutations ✅ useOptimistic 📌 Example: Show a comment instantly before the API responds ❓ When should you use it? 👉 When fast UI feedback matters more than waiting ✅ use() API 📌 Example: Read async data directly with Suspense ❓ How is it different from useEffect? 👉 Async-first rendering, built for Suspense ✅ React Compiler 📌 Example: No need to overuse useMemo / useCallback ❓ Do we still need manual optimization? 👉 Much less than before 💡 Interview tip: React 19 isn’t about new syntax — it’s about simpler code, better performance, and fewer foot-guns. Which React 19 feature are you most curious about? #React19 #ReactJS #Frontend #WebDevelopment #Interviews #LearningInPublicore

🧠 The 4 JavaScript Questions That Decide Your Offer 👇 After 8 years on both sides of interviews, I’ve seen it again and again: - Offers are often decided by fundamentals, not frameworks. - Simple-looking questions. - Deep understanding required. If you’re preparing for frontend interviews — this one can genuinely change how you answer. Read here 👇 https://lnkd.in/dNSrwqWs #FrontendDev #JavaScript #AIDevelopment #TechBlog #SoftwareEngineering #DevCommunity #Interview

⚠️ Hard Truth About Frontend Interviews If you only prepare React APIs and hooks… You’re underprepared. Most interviews in product-based companies test: • JavaScript fundamentals • Execution context & closures • Event loop • Rendering lifecycle • Performance bottlenecks • Architectural thinking React is a library. JavaScript is the foundation. Strong foundation = confident interviews. What topic do you think most frontend developers underestimate? #ReactJS #JavaScript #FrontendInterview #FrontendArchitecture #WebPerformance #ProductBasedCompany #SystemDesign #FrontendDeveloper

🚀 Today’s Mock Interview Question – JavaScript In today’s mock interview, I was asked: 👉 What is the difference between Scope and Scope Chain? Here’s how I answered: 🔹 Scope defines where a variable can be accessed in the code. JavaScript has: Global Scope Function Scope Block Scope (let and const) I explained that if a variable is declared inside a function, we cannot access it outside that function. That area is its scope. 🔹 Scope Chain is the process JavaScript uses to find variables. If a variable is not found in the current scope, JavaScript searches in the outer scope, then continues upward until it reaches the global scope. I gave a small example: let a = 10; function outer() { let b = 20; function inner() { console.log(a, b); } inner(); } I explained that inner() can access both a and b because of the scope chain. 🎯 Then I concluded: Scope → Where variables are accessible. Scope Chain → How JavaScript looks for those variables. Practicing daily mock interviews to improve my JavaScript fundamentals and communication skills. #JavaScript #FrontendDeveloper #LearningJourney #MockInterview

I once walked out of a #React interview thinking: “I know React… why did this feel so hard?” The questions weren’t tricky. They were fundamental. ❌ “Explain Virtual DOM” ❌ “Props vs State” ❌ “Why keys matter?” ❌ “useEffect dependencies?” That’s when I realized something important 👇 Most React interviews don’t test how much you’ve built — They test how clearly you understand what you already use every day. Curated with: ✅ Basic → Intermediate → Advanced questions ✅ Clear, interview-friendly explanations ✅ Real concepts interviewers care about Perfect if you’re: 🎯 Preparing for frontend/full-stack interviews 🎯 Switching companies 🎯 Revising React after long project work Because in interviews, confidence comes from clarity, not cramming. 📎 ReactJS Interview Questions PDF attached 👉 Follow Ankit Sharma Sharma for interview prep, system design, and practical engineering insights. #ReactJS #FrontendInterviews #JavaScript #WebDevelopment #SDE #InterviewPreparation

🚀 React Interview Questions – Quick Prep Guide! Sharing a handy document of important React interview questions to help you crack your next frontend interview with confidence 💻✨ Revise smart. Practice more. Get hired. 👉 Follow Renu B for more tech and interview preparation content. Credit: Respective owner #ReactJS #Frontend #JavaScript #InterviewPrep #WebDevelopment

⚛️ Top 150 React Interview Questions – 77/150 📌 Topic: Sharing Logic with Hooks ━━━━━━━━━━━━━━━━━━━━━━ 🔹 WHAT is it? Sharing logic means taking common behavior (like data fetching, scroll tracking, or online status) and moving it into a Custom Hook. This allows multiple components to reuse the same logic without rewriting code. ━━━━━━━━━━━━━━━━━━━━━━ 🔹 WHY share logic using Hooks? ♻️ No Code Duplication Write the logic once and reuse it everywhere 🧠 Separation of Concerns Components focus on UI Hooks handle the “brain work” (logic) ━━━━━━━━━━━━━━━━━━━━━━ 🔹 HOW do you share logic? Create a function that starts with use and move your state and effects into it. Example: function useOnlineStatus() { const [isOnline, setIsOnline] = useState(true); // effect logic to track online/offline return isOnline; } Usage in any component: const status = useOnlineStatus(); ━━━━━━━━━━━━━━━━━━━━━━ 🔹 WHERE / Best Practices ✔ Return Logic, Not UI Custom Hooks should return data or functions, never JSX ✔ Keep Hooks Generic Design hooks for reusable tasks (example: useFetch, useForm, useLocalStorage) ━━━━━━━━━━━━━━━━━━━━━━ 📝 SUMMARY (Easy to Remember) Sharing logic with Hooks is like a plug-and-play battery 🔋 You build the power source once, and any device (component) can plug it in to start working. ━━━━━━━━━━━━━━━━━━━━━━ 👇 Comment “React” if this handbook is helping you 🔁 Share with someone preparing for React interviews #ReactJS #ReactInterview #ReactHooks #CustomHooks #JavaScript #Top150ReactQuestions #LearningInPublic #Developers ━━━━━━━━━━━━━━━━━━━━━━