For anyone who is facing issue getting result from
$results = \JFactory::getApplication()->triggerEvent('onSomeEvent', $event);
If you gets an empty array every time do as follow.
In your plugin's onSomeEvent($event)
do not return your result.
$event must implement Joomla\Event\EventInterface . Otherwise Legacy methods will trigger and you will get empty result. Please take a note of that.
In plugin
public function onSomeEvent(Joomla\Event\EventInterface $event)
{
// your code
$result = $event->getArguments('result', []); // prevent overwriting existing results if any
$result[] = 'your result';
$event->setArguments('result', $result);
}
This will return what you set in $result
to the $results
as an array.
Do not use legacy return with J4.x