diff --git a/core/misc/collapse.es6.js b/core/misc/collapse.es6.js
index 7c6d40e..2f3a2a4 100644
--- a/core/misc/collapse.es6.js
+++ b/core/misc/collapse.es6.js
@@ -147,35 +147,38 @@
    * @param {jQuery.Event} e
    *   The event triggered.
    */
-  const showGroupingElementChild = function (e) {
-    const $item = (e.type === 'click') ? $(e.currentTarget.hash) : $(`#${location.hash.substr(1)}`);
+  const showGroupingElementChild = (e) => {
+    const $item = e.type === 'click' ? $(e.currentTarget.hash) : $(`#${location.hash.substr(1)}`);
 
     if ($item.length) {
-      // Open all (nested) parent details and set aria attributes on the summary
-      // by triggering the click event listener in details-aria.js.
+      /**
+       * Open all (nested) parent details and set aria attributes on the summary
+       * by triggering the click event listener in details-aria.js.
+       */
       $item.parents('details').not('[open]').find('> summary').trigger('click');
 
-      // Loop over all (nested) parent vertical tabs and focus them in order
-      // to reveal the children.
+      /**
+       * Loop over all (nested) parent vertical tabs and focus them in order
+       * to reveal the children.
+       */
       $item.parents('.vertical-tabs__pane').each((index, pane) => {
         $(pane).data('verticalTab').focus();
       });
 
-      // Clicking the anchor should set focus, but timing issues in Edge need this.
-      setTimeout(function() {
-        $item.focus();
+      /**
+       * Clicking the anchor should set focus, but event timing issues in Edge
+       * require a timeout.
+       */
+      setTimeout(() => {
+        $item.focus()
       }, 300, $item);
     }
   };
 
-  /**
-   * Binds a listener on fragment links to handle clicks.
-   */
+  // Binds a listener on fragment links to handle clicks.
   $(document).on('click.grouping-element-fragments', 'a[href^="#"]', showGroupingElementChild);
 
-  /**
-   * Binds a listener to handle location hash changes.
-   */
+  // Binds a listener to handle location hash changes.
   $(window).on('hashchange.grouping-element-fragments', showGroupingElementChild);
 
   // Expose constructor in the public space.