Example

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

return (
    <main>
        <button onClick={() => setCount(count + 1)}>
            Click me
        </button>
        <button onClick={() => setCount(test => test + 1)}>
            Click me
        </button>
        <p>{count}</p>
    </main>
)}

The result is the same. The number is always incremented by one when clicked. But I don't understand why the arrow function is used. Thank you