[@robin-w Moderator 5 years, 7 months ago]

first thing I would do is break this into separate functions

add_filter( 'generate_smooth_scroll_elements', 'th_scroll' ) ;

function th_scroll ( $elements ) {
  $elements[] = 'a[href*="#"]:not(.wp-show-posts-read-more)';
  return $elements;
}