(function($, Drupal) {
  Drupal.behaviors.dartExpandableTextChunks = {
    attach: function (context, settings) {
      $(".text-chunk.expandable").once(function () {
        $(this).find(".text-chunk__title").on("click", function () {
          $(this).parent().toggleClass("expanded");
          $(this).siblings(".text-chunk__content").slideToggle();
        });
      })
    }
  };

})(jQuery, Drupal);