https://www.metalocus.es/themes/custom/paltana/libraries/base/regions/region_header/region_header.js?v=11.4.7

1(function ($, Drupal, once) {
2  Drupal.behaviors.paltana_region_header = {
3    attach: function (context, settings) {
4      const headers = once('headerBehavior', '.header', context);
5      headers.forEach((header) => {
6        topbarScroll();
7      });
8
9      function topbarScroll() {
10        var didScroll;
11        var lastScrollTop = 0;
12        var delta = 5;
13        var navbarHeight = $('.topbar-fixed').outerHeight();
14
15        $(window).scroll(function (event) {
16          didScroll = true;
17        });
18
19        setInterval(function () {
20          if (didScroll) {
21            hasScrolled();
22            didScroll = false;
23          }
24        }, 250);
25
26        function hasScrolled() {
27          var st = $(this).scrollTop();
28
29          if(st == 0) {
30            $('.topbar-fixed').addClass('is-top');
31          } else {
32            $('.topbar-fixed').removeClass('is-top');
33          }
34
35          // Make sure they scroll more than delta
36          if (Math.abs(lastScrollTop - st) <= delta)
37            return;
38
39          // If they scrolled down and are past the navbar, add class .nav-up.
40          // This is necessary so you never see what is "behind" the navbar.
41          if (st > lastScrollTop && st > navbarHeight) {
42            // Scroll Down
43            $('.topbar-fixed').removeClass('nav-down').addClass('nav-up');
44          } else {
45            // Scroll Up
46            if (st + $(window).height() < $(document).height()) {
47              $('.topbar-fixed').removeClass('nav-up').addClass('nav-down');
48            }
49          }
50
51          lastScrollTop = st;
52        }
53      }
54    }
55  };
56}(jQuery, Drupal, once));
57