showIndex for Kirby

showIndex.php

<?php

/**
  Translates Kirby's index() function to a nested list by building a string of markdown text then converting it to HTML. Useful for navigation menus of unknown depth.
  @param must be an index() object
  @return string of HTML
*/
function showIndex($pages) {
  
  // Initialize output string
  $output = '';

  // Get the initial nesting level
  $inital_level = substr_count($pages->data[0],'/');

  // Loop through pages
  foreach ($pages->data as $page) {

    // Set the page's indent level. Markdown requires 4 spaces for each level of depth.
    $level = $page->depth() - $intial_level - 2;
    if ($level > 0) {
      $prefix = str_repeat('    ', $page->depth() - $intial_level - 2);
    } else {
      $prefix = '';
    }

    // Manually build the output string in kirbytext/markdown format
    $count = $page->children()->filterBy('template','product')->visible()->count();
    $output .= $prefix.'- <a href="'.$page->url().'" title="'.$page->title().'"';
    if ($page->isOpen()) $output .= ' class="active"';
    $output .= '>'.$page->title();
    if ($count) $output .= '<span>'.$page->children()->filterBy('template','product')->count().'</span>';
    $output .= '</a>'."\n";
    
  }

  // Return the list as HTML
  return kirbytext($output);
}

?>

Put this file in your plugins/ folder, then use it in your templates like this:

$categories = $pages->index()->filterBy('template','category');
echo showIndex($categories);