Add category count to category menu items in Wordpress.

gistfile1.txt

// Short code pour le nombre d'items dans une catégorie
add_shortcode('categoryCount', 'nbProductsCategoryShortcode');
function nbProductsCategoryShortcode ($attributes = []) {
    global $wpdb;

    $attributes = shortcode_atts([
        'category' => null,
    ], $attributes);

    $category = $attributes['category'];

    if (empty($category)) return;

    $terms = get_terms( 'product_cat' );

    $count = 0;

    foreach ($terms as $term) {
        if ($term->name == $category) $count = $term->count;
    }

    return '<span class="category-count">('.$count.')</span>';
}

// Ajout du shortcode aux items du menu
add_filter('wp_nav_menu_objects', 'applyCategoryCountToMenu');
function applyCategoryCountToMenu ($items) {
    foreach ($items as $key => $menuItem) {
        if ($menuItem->type != 'taxonomy') continue;
        $menuItem->title = $menuItem->title . ' ' . do_shortcode('[categoryCount category="'.$menuItem->title.'"]');
    }
    return $items;
}