Why are these different?

by Lakshay Akula

HTML

<body>
<button class='button' data-thing='hello'>
  Click Me
</button>
</body>

JavaScript

const button = document.querySelector('.button');

function logThisA(event) {
	console.log(this.dataset.thing || '');
}

const logThisB = event => {
	console.log(this.dataset.thing || '');
}

button.addEventListener('click', logThisA);
button.addEventListener('click', logThisB);


console.log(button);