Q338- Create a simple React Counter component that will increase the count every second.

Simple React Counter that automatically increases the count every second.

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✅ Counter Component (Auto Increment)

import { useState, useEffect } from "react";

function Counter() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    const timer = setInterval(() => {
      setCount(prev => prev + 1);
    }, 1000);

    return () => clearInterval(timer); // cleanup
  }, []);

  return <h2>Count: {count}</h2>;
}

export default Counter;

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🧠 How It Works

• useState stores the count
• useEffect runs once on mount ([])
• setInterval increments every 1 second
• Cleanup prevents memory leaks on unmount

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🎯 Short Interview Answer

Use useEffect with setInterval to update state every second and clear the interval on unmount.

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⭐ One-line summary

useEffect + setInterval creates an auto-incrementing counter safely.