Next.js Counter with useMemo - Next-js Typing CST Test

Next.js Counter with useMemo — Next-js Code

Uses useMemo to compute double of count for demonstration.

import { useState, useMemo } from 'react';

export default function Counter() {
  const [count, setCount] = useState(0);
  const [isDark, setIsDark] = useState(false);
  const double = useMemo(() => count * 2, [count]);

  return (
    <div className={isDark ? 'dark-theme' : 'light-theme'} style={{ padding: '2rem', textAlign: 'center' }}>
      <h2>Counter: {count} (Double: {double})</h2>
      <button onClick={() => setCount(count + 1)}>+</button>
      <button onClick={() => setCount(count - 1)}>-</button>
      <button onClick={() => setCount(0)}>Reset</button>
      <button onClick={() => setIsDark(!isDark)}>Switch Theme</button>
      <style jsx>{`
        .dark-theme { background: #222; color: #eee; min-height: 100vh; }
        .light-theme { background: #fff; color: #000; min-height: 100vh; }
        button { margin: 0 0.5rem; }
      `}</style>
    </div>
  );
}

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