Check what "type" a menu item is

Question

The question

I would like to check what type of menu item each item in my menu is i.e. is it a Page, Category, or Custom link.

What I want to achieve

I want to create a menu made up of categories and pages links. Of the categories in the menu I only want to show those which contain posts. Page links will always show.

This menu will be used on an ecommerce site with a catalogue that changes constantly. Making a dynamic menu which hides empty categories removes the need to constantly update the menu in the admin area.

What I have now

A custom walker menu based on this SE post which successfully hides links to empty categories by adding logic to the start_el function. Unfortunately my logic hides pages links too

Full walker menu function:

function cs_modify_nav_menu_args( $args ){
if( 'primary-menu' == $args['theme_location'] ){
    $args['walker'] = new cs_walker_nav_menu();
}
return $args;
}

class cs_walker_nav_menu extends Walker_Nav_Menu {
// filter empty categories and add main/sub classes to li's and links
function start_el(  &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
    global $wp_query;


    if(!is_page($item->ID)){

        $non_empty_categories = get_categories(array('taxonomy' => 'product_cat'));
        $empty_categories = array();
        $is_empty = true;
        // check menu items are for an empty category
        foreach ( $non_empty_categories as $cat )
            if ($item->object_id === $cat->term_id)
                $is_empty = false;
            // if it is empty add it to array
            if ($is_empty)
                $empty_categories[] = $item->ID;
        // Don't build nav item for items in the is_empty array
        foreach( $empty_categories as $category_to_skip )
            if( $item->ID == $category_to_skip )
                return $output;
    }

    $indent = ( $depth > 0 ? str_repeat( "\t", $depth ) : '' ); // code indent

    // depth dependent classes
    $depth_classes = array(
        ( $depth == 0 ? 'main-menu-item' : 'sub-menu-item' ),
        ( $depth >=2 ? 'sub-sub-menu-item' : '' ),
        ( $depth % 2 ? 'menu-item-odd' : 'menu-item-even' ),
        'menu-item-depth-' . $depth
    );
    $depth_class_names = esc_attr( implode( ' ', $depth_classes ) );

    // passed classes
    $classes = empty( $item->classes ) ? array() : (array) $item->classes;
    $class_names = esc_attr( implode( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item ) ) );

    // build html
    $output .= $indent . '<li id="nav-menu-item-'. $item->ID . '" class="' . $depth_class_names . ' ' . $class_names . '">';

    // link attributes
    $attributes  = ! empty( $item->attr_title ) ? ' title="'  . esc_attr( $item->attr_title ) .'"' : '';
    $attributes .= ! empty( $item->target )     ? ' target="' . esc_attr( $item->target     ) .'"' : '';
    $attributes .= ! empty( $item->xfn )        ? ' rel="'    . esc_attr( $item->xfn        ) .'"' : '';
    $attributes .= ! empty( $item->url )        ? ' href="'   . esc_attr( $item->url        ) .'"' : '';
    $attributes .= ' class="menu-link ' . ( $depth > 0 ? 'sub-menu-link' : 'main-menu-link' ) . '"';

    $item_output = sprintf( '%1$s<a%2$s>%3$s%4$s%5$s</a>%6$s',
        $args->before,
        $attributes,
        $args->link_before,
        apply_filters( 'the_title', $item->title, $item->ID ),
        $args->link_after,
        $args->after
    );

    // build html
    $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
}
}

Attempted solutions

The nav_menu_item object does not supply the menu item type.

Passing $item->ID to is_page does not return. I believe $item->ID is the menu item ID not a post ID.

Answer 1

Fortunately, there is an easy fix for this.

The $item in the Walker delivers Classes, and if the menu item is an archive, you get one of those:

• menu-item-type-taxonomy (general)
• menu-item-object-product_cat (product_cat == taxonomyname)

as well as

• $item->type == 'taxonomy'
• $item->object == 'your_taxonomy'

If you want this logic to work for various Archives (not just the product_cat) you need to change the taxonomy as well - again, $item conveniently delivers your $taxonomy as $item->object.

Now you only need to change your if and the taxonomy in your Walker

if( $item->type == 'taxonomy' ) {

    $non_empty_categories = get_categories( array( 'taxonomy' => $item->object ) );

    // ... The rest of your logic works fine

}

Should work just fine :)