Limit number of events shown only on specific pages

The use case for this snippet is a calendar, e.g. using the list view, that displays the next X upcoming events on the home page, with a link to view the full grid view calendar below.

On the home page calendar, we only want a limited number of events to be shown, but we don't want to alter the number of events across all calendars on the site.

This example snippet will limit a calendar on the site's static home page to the next 4 events that occur in time, starting from today.

This snippet could be altered to check for different criteria, such as post ID, if you have a calendar on a page other than the static home page that you want to alter the number of events for.

To use this snippet, add it via functions.php, a custom functionality plugin, or your favorite code snippets plugin.

add_filter( 'piecal_events_array_filter', 'piecal_custom_limit_events', 10, 4 );

function piecal_custom_limit_events( $eventsArray, $rangeStart = null, $rangeEnd = null, $appendOffset ) {
// Only alter the events array on the static front page
if( !is_front_page() ) return $eventsArray;

// First, we need to make sure only events on today or after are in the events array
$eventsArray = array_filter($eventsArray, function($event) {
	// First, ensure that 'start' is in a comparable date format
	$eventStartDate = new DateTime($event['start']);
	$currentDate = new DateTime(); // This defaults to "now"

	// Return true for events starting today or in the future
	return $eventStartDate >= $currentDate;
});

// Reset the indexes after filtering
$eventsArray = array_values($eventsArray);

// Next, we need to limit how many are actually in the array
// In this case, I'm keeping the first 4.
$eventsArray = array_slice($eventsArray, 0, 4);

return $eventsArray;
}