https://www.bnf.fr/modules/custom/dropdown_language/js/dropdown_language_selector.js?v=8.9.20

1/**
2 * @file
3 * Dropdown language selector js.
4 */
5
6(function ($, Drupal) {
7  'use strict';
8
9  Drupal.behaviors.dropdownLanguagesSelector = {
10    attach: function(context, settings) {
11      $('.dropdown-language-item .active-language', context).once('dropdown-language-selector')
12        .click(function(e) {
13          var $wrapper = $(this).closest('.dropbutton-wrapper');
14          if ($wrapper.length > 0) {
15            e.preventDefault();
16            e.stopPropagation();
17            $wrapper.toggleClass('open');
18          }
19        });
20    }
21  };
22
23})(jQuery, Drupal);