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Countdown Timer Component

Master the art of building countdown timers in React using useEffect hook - perfect for quiz apps, games, and time-sensitive applications.

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Building a Responsive Carousel Component in React

Learn how to build a fully functional, responsive carousel component from scratch in React with autoplay, looping, and responsive design features.

File Explorer - Machine Coding Question

Build a file explorer component using React with folder/file creation, navigation, and tree structure management

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⏰ Machine Coding Challenge: Countdown Timer ComponentProblem Statement🧠 The Big Picture - What Are We Actually Building?Core Concepts You Need to Understand1. What is State in React?2. Why Do We Need useEffect for Timers?3. The Timer Logic - Step by Step🔄 The Flow - How Everything ConnectsStep 1: Quiz StartsStep 2: Every Second (This is the useEffect magic!)Step 3: User Clicks an AnswerStep 4: Quiz EndsThe Tricky Parts ExplainedWhy the Cleanup Function?Why These Dependencies?Why Check if (showResult) return;?Real-World Example - Let's Trace Through ItCodeWhy This Approach Works🚨 Common Mistakes Students Make🔗 Related Challenges