Add post/page slug to body class

// functions.php
function sp_add_slug_body_class( $classes ) {
  global $post;
  if ( isset( $post ) ) {
    $classes[] = $post->post_type . '-' . $post->post_name;
  }
  return $classes;
}
add_filter( 'body_class', 'sp_add_slug_body_class' );;