Drupal 8 Tip: Add unique class to the body tag from page path (or route)
To add a custom, unique class to the body tag based on the page's path alias (route name), first add the following to your .theme file:
function yourtheme_preprocess_html(&$variables) {
$variables['route'] = str_replace('.','-',\Drupal::routeMatch()->getRouteName());
}If you don't already have a theme override for the html.html.twig file, create one by copying the html.html.twig file from your base theme (e.g. classy). Then, add the route variable to the body_classes variable:
{%
set body_classes = [
logged_in ? 'user-logged-in',
not root_path ? 'page-frontpage' : 'page-' ~ root_path|clean_class,
node_type ? 'node--type-' ~ node_type|clean_class,
db_offline ? 'db-offline',
<strong>route,</strong>
]
%}