https://tf1pro.com/themes/custom/tf1pro_theme/js/masthead.js?tm9rs4

1(function ($, Drupal, drupalSettings) {
2  Drupal.behaviors.tf1Masthead = {
3    attach: function (context, settings) {
4      const mast = once(
5        "tf1Masthead",
6        '.view-masthead .slick [data-slick-index="0"]',
7        context
8      );
9      $(mast).each(function () {
10        $(arguments[1]).addClass("animation");
11      });
12      const mastBefore = once(
13        "tf1MastheadBefore",
14        ".view-masthead .slick",
15        context
16      );
17      $(mastBefore).on(
18        "beforeChange",
19        function (slick, currentSlide, nextSlide) {
20          $(
21            '.view-masthead [data-slick-index="' + nextSlide + '"]'
22          ).removeClass("animation");
23        }
24      );
25      const mastAfter = once(
26        "tf1MastheadAfter",
27        ".view-masthead .slick",
28        context
29      );
30      $(mastAfter).on("afterChange", function (slick, currentSlide) {
31        $(
32          '.view-masthead [data-slick-index="' +
33            currentSlide.currentSlide +
34            '"]'
35        ).addClass("animation");
36      });
37    },
38  };
39})(jQuery, Drupal, drupalSettings);