{No_Notes} Not Working

I’ve made a few changes to your no_notes code and tested it to be sure that it works.

function em_event_output_condition_filter($replacement, $condition, $match, $EM_Event) {
	// Checks for has_notes conditional
	if (is_object($EM_Event) && preg_match('/^has_(notes)$/', $condition, $matches)) {
		if (isset($EM_Event->$matches[1]) && !empty($EM_Event->$matches[1])) {
			$replacement = preg_replace("/\{\/?$condition\}/", '', $match);
		} else {
			$replacement = '';
		}
	}

	// Checks for no_notes conditional
	if (is_object($EM_Event) && preg_match('/^no_(notes)$/', $condition, $matches)) {
		if (!isset($EM_Event->$matches[1]) || empty($EM_Event->$matches[1])) {
			$replacement = preg_replace("/\{\/?$condition\}/", '', $match);
		} else {
			$replacement = '';
		}
	}
	return $replacement;
}
add_filter('em_event_output_condition', 'em_event_output_condition_filter', 1, 4);

This is an example of how it could be used:

{has_notes} This text will show up if notes have been filled out: #_EVENTNOTES {/has_notes}

{no_notes} This text will only show up if notes is empty. {/no_notes}

No problem. This can be made to work for locations as well, but the $EM_Location object doesn’t have a ‘notes’ property. Instead it’s called ‘post_content’, yet represents the same field. Due to the naming differences you either need to change the conditional to be {has_post_content} {/has_post_content} {no_post_content} {/no_post_content}, or keep the same naming convention (for consistency sake between events and locations) and hardcode the post_content property into the conditional function.

I’ve added the functioning (and tested) code for {has_notes} and {no_notes} for locations below:

function em_location_output_condition_filter($replacement, $condition, $match, $EM_Location) {
	// Checks for has_notes conditional
	if (is_object($EM_Location) && preg_match('/^has_(notes)$/', $condition, $matches)) {
		if (isset($EM_Location->post_content) && !empty($EM_Location->post_content)) {
			$replacement = preg_replace("/\{\/?$condition\}/", '', $match);
		} else {
			$replacement = '';
		}
	}

	// Checks for no_notes conditional
	if (is_object($EM_Location) && preg_match('/^no_(notes)$/', $condition, $matches)) {
		if (!isset($EM_Location->post_content) || empty($EM_Location->post_content)) {
			$replacement = preg_replace("/\{\/?$condition\}/", '', $match);
		} else {
			$replacement = '';
		}
	}
	return $replacement;
}
add_filter('em_location_output_condition', 'em_location_output_condition_filter', 1, 4);