Conditionally highlight WordPress menu items

conditional-highlight

//This is useful if you want to highlight menu items conditionally.
//Example highlight the 'Blog' menu item when you are on a single post
//Highlight a custom link menu item when you are on a custom post type
//http://www.tammyhartdesigns.com/wordpress/highlight-menu-item-for-custom-post-types/

add_filter('nav_menu_css_class', 'thd_menu_classes', 10, 2);
function thd_menu_classes($classes, $item)
{

    $post_types = array(
        'news_notes' => '/in-the-media',
        'announcement' => '/announcements'
    );

    if (get_post_type() == 'news_notes' || is_archive('news_notes')) {
        // find the url you want and add the class you want
        if ($item->url == '/in-the-media') {
            $classes = str_replace('menu-item', 'menu-item active', $classes);
            remove_filter('nav_menu_css_class', 'thd_menu_classes', 10, 2);
        }
    } elseif (get_post_type() == 'announcement') {
        // find the url you want and add the class you want
        if ($item->url == '/announcements') {
            $classes = str_replace('menu-item', 'menu-item active', $classes);
            remove_filter('nav_menu_css_class', 'thd_menu_classes', 10, 2);
        }
    }

    return $classes;
}

/*
 * Highlight parent-page menu items on child-pages
 */
add_filter('nav_menu_css_class', 'thd_menu_classes', 10, 2);
function thd_menu_classes($classes, $item)
{
    global $post;

    if ($post->post_parent) {
        $post_data = get_post($post->post_parent);
        $parent_name = $post_data->post_name;

        if(strpos($item->url,$parent_name)) {
            $classes = str_replace('menu-item', 'menu-item active', $classes);
            remove_filter('nav_menu_css_class', 'thd_menu_classes', 10, 2);
        }
    }

    return $classes;
}