【プラグインなし】WordPressでリッチリザルト対応のぱんくずリストを実装する

// パンくずリスト
function breadcrumb(){
	global $post;
	$str ='';
	$item_prop_content = 0;

	if(!is_home()&&!is_admin()){
		$item_prop_content++;
		// $str.= '<a href="'.home_url().'" class="home" itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><i class="fas fa-home" title="home"></i><meta itemprop="position" content="'.strval($item_prop_content).'" /></a> > ';
		$str.= '<div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a href="'.home_url().'" class="home" itemprop="item"><span><i class="fas fa-home" title="home"></i><span class="no_v" style="display:none" itemprop="name">ホーム</span></span></a> > <meta itemprop="position" content="'.strval($item_prop_content).'" /></div>';
		if(is_category()) {
			$cat = get_queried_object();
			if($cat->parent != 0){
				$ancestors = array_reverse(get_ancestors( $cat->cat_ID, 'category' ));
				foreach($ancestors as $ancestor){
					$item_prop_content++;
					$str.='<div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><span itemprop="name">'. get_cat_name($ancestor) .'</span><meta itemprop="position" content="'.strval($item_prop_content).'" /> > </div>';
				}
			}
			$item_prop_content++;
			$str.='<div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a href="'. get_category_link($cat->term_id). '" itemprop="item"><span itemprop="name">'. $cat-> cat_name . '</span></a><meta itemprop="position" content="'.strval($item_prop_content).'" /></div>';
		} elseif(is_page()){
			$post_name = $post->post_title;
			if($post->post_parent != 0 ){
				$ancestors = array_reverse(get_post_ancestors( $post->ID ));
				foreach($ancestors as $ancestor){
					$item_prop_content++;
					$str.='<div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a href="'. get_permalink($ancestor).'" itemprop="item"><span itemprop="name">'. get_the_title($ancestor) .'</span></a><meta itemprop="position" content="'.strval($item_prop_content).'" /></div>';
				}
			}
			$item_prop_content++;
			$str.=' <div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><span itemprop="name">'.$post_name.'</span><meta itemprop="position" content="'.strval($item_prop_content).'" /></div>';
		} elseif(is_single()){
			$categories = get_the_category($post->ID);
			$cat = $categories[0];
			$post_name = $post->post_title;
			if($cat->parent != 0){
				$ancestors = array_reverse(get_ancestors( $cat->cat_ID, 'category' ));
				foreach($ancestors as $ancestor){
					$item_prop_content++;
					$str.='<div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a href="'. get_category_link($ancestor).'" itemprop="item"><span itemprop="name">'. get_cat_name($ancestor). '</span></a><meta itemprop="position" content="'.strval($item_prop_content).'" /> > </div>';
				}
			}
			$item_prop_content++;
			$str.='<div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><a href="'. get_category_link($cat->term_id). '" itemprop="item"><span itemprop="name">'. $cat->cat_name . '</span></a><meta itemprop="position" content="'.strval($item_prop_content).'" /></div> > ';
			$item_prop_content++;
			$str.='<div itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem"><span itemprop="name">'.$post_name.'</span><meta itemprop="position" content="'.strval($item_prop_content).'" /></div>';
		} else{
			$str.='<div>'. wp_title('', false) .'</div>';
		}
	}
	echo $str; 
}

<?php breadcrumb(); ?>