hack

hack.php

$cat_counts = (new F\MaybeEmpty($full_query->get_posts()))
	->bind($posts ==> array_map($p ==> wp_get_post_categories($p->ID), $posts))
	->bind('tft\fp\flatten')
	->bind($cats ==> F\reduce($cats, function($carry, $id) {
		$carry[$id]++;
		return $carry;
	}), [])
	->extract();