gistfile1.php

<?php 

/**
 * Remove the id="" on nav menu items
 * Return 'menu-slug' for nav menu classes
 */
function roots_nav_menu_css_class($classes, $item) {
  $slug = sanitize_title($item->title);
  if (is_singular('post')) {
    $active_class = '';
  } else {
    $active_class = 'active';
  }
  $classes = preg_replace('/(current(-menu-|[-_]page[-_])(item|parent|ancestor))/', $active_class, $classes);
  $classes = preg_replace('/^((menu|page)[-_\w+]+)+/', '', $classes);
 
  $classes[] = 'menu-' . $slug;
 
  $classes = array_unique($classes);
 
  return array_filter($classes, 'is_element_empty');
}
add_filter('nav_menu_css_class', 'roots_nav_menu_css_class', 10, 2);
add_filter('nav_menu_item_id', '__return_null');

?>