counter.js

import React, { useState } from 'react'

const SimpleButton = ({ onClick, children }) => (
  <button onClick={onClick}>{children}</button>
);

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

  const increment = () => {
    setCount(count + 1);
  };
  
  const decrement = () => {
    setCount(count - 1);
  };

  return (
    <>
      Count: {count} <br />
      <SimpleButton onClick={increment}>+</SimpleButton>
      <SimpleButton onClick={decrement}>-</SimpleButton>
    </>
  );
}