https://www.imageworks.com/themes/custom/topplus/js/custom/in-page-navigation-scroll.js?v=11.4.5

1(function ($, Drupal, drupalSettings, once) {
2  Drupal.behaviors.inPageNav = {
3    attach: function (context) {
4
5      $(once('inPageNav', 'a[href*="#"]', context)).on('click', function (e) {
6
7        if (!this.hash || this.hash === '#') {
8          return;
9        }
10
11        if (
12          this.pathname !== window.location.pathname ||
13          this.hostname !== window.location.hostname
14        ) {
15          return;
16        }
17
18        // Find the target using the native DOM API.
19        var target = document.getElementById(this.hash.substring(1));
20
21        if (!target) {
22          return;
23        }
24
25        var $target = $(target);
26        var targetOffset = $target.offset();
27
28        // jQuery couldn't determine the position.
29        if (!targetOffset) {
30          return;
31        }
32
33        e.preventDefault();
34
35        var adminHeight = parseInt($('body').css('paddingTop'), 10) || 0;
36
37        var offset =
38          drupalSettings?.topplus?.inPageNavigation?.inPageNavigationOffset || 0;
39
40        $('html, body').animate({
41          scrollTop: targetOffset.top - offset - adminHeight
42        }, 1000);
43
44        if (history.pushState) {
45          history.pushState(null, '', this.hash);
46        } else {
47          window.location.hash = this.hash;
48        }
49      });
50    }
51  };
52})(jQuery, Drupal, drupalSettings, once);