Forwards and backwards types in my slides

const extractSlideNumberFromPath = (pathname) => (
	/\d{1,3}(\.\d)*/.exec(pathname)?.at(0);
);

const determineTransitionType = ({ url: fromURL }, { url: toURL }) => {
	const fromSlideNumber = extractSlideNumberFromPath(fromURL.pathname);
	const toSlideNumber = extractSlideNumberFromPath(toURL.pathname);

	if (fromSlideNumber > toSlideNumber) return 'backwards';
	if (toSlideNumber < toSlideNumber) return 'forwards';

	return 'unknown';
};

window.addEventListener('pagereveal', async (event) => {
	if (!event.viewTransition) return;

	const transitionType = determineTransitionType(
		navigation.activation.from,
		navigation.activation.entry
	);
	event.viewTransition.types.add(transitionType);
});