Primary menu behavior

Functions.php: Add primary location fallback
Nav.php : Check if menu is empty

functions.php

@@ -230,4 +230,49 @@ function add_allowed_tags($tags) {
     return $tags;
 }
 add_filter('wp_kses_allowed_html', 'add_allowed_tags');
+
+/*the fallback from wp_nav_menu, we want to replicate the output of wp_page_menu to be similar to wp_nav_menu
+@param args, it comes from the wp_nav_menu arguments*/
+function hale_main_nav_fallback($args) {
+	$args['echo'] = 0; // don't echo the output yet.
+	$nav_menu = wp_page_menu($args);
+	if(!empty($nav_menu)){
+		$doc = new DOMDocument();
+		@$doc->loadHTML($nav_menu);//surpress the warnings
+		$data = $doc->getElementsByTagName('li');
+		//the default behaviour of wp_page_menu is that it wraps the list items with a ul and div
+		//menu_class is for div in wp_page_menu, but is for the ul in wp_nav_menu
+		//create the container, if any
+		//container class and id come from wp_nav_menu arguments. Which is not used in wp_page_menu.
+		if($args['container'] != false) {
+			$attributes = (!empty($args['container_class'])?' class="'.$args['container_class'].'"':'');
+			$attributes .= (!empty($args['container_id'])?' id="'.$args['container_id'].'"':'');
+			if($args['container'] == 'nav') {
+				echo '<nav'.$attributes.'>';
+			} else {
+				echo '<div'.$attributes.'>';
+			}
+
+		}
+		$attributes = (!empty($args['menu_class'])?' class="'.$args['menu_class'].'"':'');
+		$attributes .= (!empty($args['menu_id'])?' id="'.$args['menu_id'].'"':'');
+		echo '<ul'.$attributes.'>';
+		if($data->length > 0) {
+			foreach($data as $item) {		
+				echo $item->ownerDocument->saveXML($item);//saveHTML wouldn't accept it as paramater.
+			}
+		}
+		echo '</ul>';
+		//close the container, if any
+		if($args['container'] != false) {
+			if($args['container'] == 'nav') {
+				echo '</nav>';
+			} else {
+				echo '</div>';
+			}
+
+		}
+	}	
+	return;
+}
 ?>

inc/nav.php

@@ -14,19 +14,24 @@
 	<a class="skip-link screen-reader-text sr-only" href="#content">
 		<?php _e( 'Skip to content', 'cs' ); ?></a>
 	<div class="collapse navbar-collapse" id="primary-nav">
-		<?php 
-			wp_nav_menu( 
-			array( 
-				'menu' => 'primary', /* menu name */
-				'menu_class' => 'nav navbar-nav'.$nav1.' '.$nav2,
-				'theme_location' => 'primary', /* where in the theme it's assigned */
-				'container' => false, /* container class */
-				'fallback_cb' => 'hale_main_nav_fallback',
-				'items_wrap' =>	'<ul id="%1$s" class="%2$s"><li><a href="'.home_url().'">Home</a></li>%3$s</ul>',
-				'walker' => new Bootstrap_Nav_Walker()/*,
-				'with_search' => true*/
-			)
-		);
+		<?php
+			$menu_at_primary_location = get_nav_menu_locations()['primary'];
+			$items = wp_get_nav_menu_items( $menu_at_primary_location );
+			if(empty($items)){
+				echo '<ul class="nav navbar-nav"><li><a href="'.home_url().'">Home</a></li></ul>';
+			} else {
+				$menu = wp_nav_menu( 
+					array(
+						'menu_class' => 'nav navbar-nav'.$nav1.' '.$nav2,
+						'theme_location' => 'primary', /* where in the theme it's assigned */
+						'container' => false, /* container class */
+						'fallback_cb' => 'hale_main_nav_fallback',
+						'items_wrap' =>	'<ul id="%1$s" class="%2$s"><li><a href="'.home_url().'">Home</a></li>%3$s</ul>',
+						'walker' => new Bootstrap_Nav_Walker()/*,
+						'with_search' => true*/
+					)
+				);			
+			}
 		?>
 		<div class="visible-xs-block">
 		<div class="navbar-form navbar-right">