internalLink.js

/**
 * Animate navigation for anchor links on the same page
 * // TODO: rewrite in vanilla
 */
jQuery('a[href^="#"]').on('click', function(event) {
   event.preventDefault();
   var $href = jQuery(this).attr('href'),
       $toScroll = jQuery($href),
       scrollToY = $toScroll.length ? $toScroll.offset().top - 0 : 0;

   if ($href !== '#') {
       jQuery('html,body').animate({scrollTop: scrollToY}, 500);
   }
});