How to var_dump nav menu items from anywhere?

1 comment

1. The items are set up in wp_nav_menu(). There is a useful filter you can use: 'wp_nav_menu_objects'. It offers the items as $sorted_menu_items and the arguments of the wp_nav_menu() call as $args.

   From wp-includes/nav-menu-template.php::wp_nav_menu():

   $sorted_menu_items = apply_filters( 'wp_nav_menu_objects', $sorted_menu_items, $args );
   

   So …

   • hook into this filter,
   • store the data somewhere,
   • return the $sorted_menu_items unchanged and
   • print the collected data after all menus are done.

   In my following example I print the data on 'shutdown' – that’s the latest hook WordPress fires.

   <?php # -*- coding: utf-8 -*-
   /**
    * Plugin Name: T5 Collect Nav Menu Items
    * Description: Appends debug information about currently processed nav menu items to pages.
    */
   
   add_filter( 'wp_nav_menu_objects', array ( 'T5_Nav_Menu_Collector', 'collect' ), 99, 2 );
   
   class T5_Nav_Menu_Collector
   {
       /**
        * Stores the data
        * @type array
        */
       protected static $collection = array ();
   
       /**
        * Collect nav menu data.
        *
        * @wp-hook wp_nav_menu_objects
        * @param   array $sorted_menu_items
        * @param   array $args
        * @return  array $sorted_menu_items   Not changed.
        */
       public static function collect( $sorted_menu_items, $args )
       {
           // Since we *know* we have data, we register the print action.
           add_action( 'shutdown', array ( __CLASS__, 'print_collection' ) );
   
           self::$collection[] = array(
               'args'  => $args,
               'items' => $sorted_menu_items
           );
           return $sorted_menu_items;
       }
   
       /**
        * Dump the collected data.
        *
        * @wp-hook shutdown
        * @return  void
        */
       public static function print_collection()
       {
           $output = htmlspecialchars( print_r( self::$collection, TRUE ) );
           print "<pre><b>Nav Menu Data</b>nn$output</pre>";
       }
   }
   

   If there is no nav menu – nothing happens. But if we could collect some data, we get a nice long list at the end of a document with all item properties we can use in other filters.

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