https://www.trade.gov/themes/custom/ita/components/03-organisms/sidenav-menu/sidenav.js?tlu5k9

1(function ($, Drupal) {
2  'use strict';
3
4  Drupal.behaviors.sidenav = {
5    'attach': function (context) {
6      // remove grandchild triggers, if present
7      $('.ita-sidenav__menu-item .ita-sidenav__menu-item .ita-sidenav__toggle').remove();
8
9      $('li.ita-sidenav__menu-item').each(function(index) {
10        if ($(this).hasClass('is-active')) {
11          $(this).find('.ita-sidenav__menu-link').addClass('is-active');
12        }
13      });
14
15      $('.ita-sidenav__toggle').on('click', function(e) {
16        e.preventDefault();
17        var triggerDOM = $(this);
18        var triggerParentDOM = triggerDOM.parent();
19        var closedIconDOM = $(triggerDOM).find('.ita-sidenav__toggle--closed'); // closed == show; could be multiple
20        var openedIconDOM = $(triggerDOM).find('.ita-sidenav__toggle--open'); // open == hide; should be one or zero
21
22        // handle open and close of triggered submenu
23        if (triggerParentDOM.hasClass('ita-sidenav__menu-item--expanded')) {
24          // close the triggered DOM
25          triggerParentDOM.removeClass('ita-sidenav__menu-item--expanded')
26            .removeClass('is-active')
27            .addClass('ita-sidenav__menu-item--collapsed')
28            .attr('aria-expanded', false);
29          closedIconDOM.addClass('ita-sidenav__toggle--show').removeClass('ita-sidenav__toggle--hide');
30          openedIconDOM.addClass('ita-sidenav__toggle--hide').removeClass('ita-sidenav__toggle--show');
31        }
32        else {
33          // open the triggered DOM
34          triggerParentDOM.addClass('ita-sidenav__menu-item--expanded')
35            .addClass('is-active')
36            .removeClass('ita-sidenav__menu-item--collapsed')
37            .attr('aria-expanded', true);
38          closedIconDOM.removeClass('ita-sidenav__toggle--show').addClass('ita-sidenav__toggle--hide');
39          openedIconDOM.removeClass('ita-sidenav__toggle--hide').addClass('ita-sidenav__toggle--show');
40        }
41      });
42    }
43  };
44})(jQuery, Drupal);