diff --git a/core/misc/ajax.es6.js b/core/misc/ajax.es6.js
index 6bded620ca..79b75bd85d 100644
--- a/core/misc/ajax.es6.js
+++ b/core/misc/ajax.es6.js
@@ -1052,9 +1052,9 @@
         responseDataNodes = $.parseHTML(trimmedData, true);
       }
       // Check every node for it's type to decide if wrapping is necessary.
-      const onlyElementNodes = responseDataNodes.every(function (element) {
-        return element.nodeType === Node.ELEMENT_NODE || element.nodeType === Node.COMMENT_NODE;
-      });
+      const onlyElementNodes = responseDataNodes.every(
+        element => element.nodeType === Node.ELEMENT_NODE || element.nodeType === Node.COMMENT_NODE,
+      );
 
       // When there are only element and/or comment nodes in the response, no
       // extra wrapping necessary.
@@ -1084,6 +1084,9 @@
         case 'empty':
         case 'remove':
           Drupal.detachBehaviors($wrapper.get(0), settings);
+          break;
+        default:
+          break;
       }
 
       // Add the new content to the page.
@@ -1111,9 +1114,9 @@
       // `#ajax['wrapper']` to be optional.
       if ($newContent.parents('html').length) {
         // Attach behaviors to all element nodes.
-        $newContent.each(function () {
-          if (this.nodeType === Node.ELEMENT_NODE) {
-            Drupal.attachBehaviors(this, settings);
+        $newContent.each((index, element) => {
+          if (element.nodeType === Node.ELEMENT_NODE) {
+            Drupal.attachBehaviors(element, settings);
           }
         });
       }
diff --git a/core/misc/ajax.js b/core/misc/ajax.js
index 2177c7bc71..65659e0f53 100644
--- a/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -514,6 +514,9 @@
         case 'empty':
         case 'remove':
           Drupal.detachBehaviors($wrapper.get(0), settings);
+          break;
+        default:
+          break;
       }
 
       $wrapper[method]($newContent);
@@ -532,9 +535,9 @@
       }
 
       if ($newContent.parents('html').length) {
-        $newContent.each(function () {
-          if (this.nodeType === Node.ELEMENT_NODE) {
-            Drupal.attachBehaviors(this, settings);
+        $newContent.each(function (index, element) {
+          if (element.nodeType === Node.ELEMENT_NODE) {
+            Drupal.attachBehaviors(element, settings);
           }
         });
       }
diff --git a/core/modules/system/tests/modules/ajax_test/js/insert-ajax.es6.js b/core/modules/system/tests/modules/ajax_test/js/insert-ajax.es6.js
index 94da75c135..5a3a49dcfb 100644
--- a/core/modules/system/tests/modules/ajax_test/js/insert-ajax.es6.js
+++ b/core/modules/system/tests/modules/ajax_test/js/insert-ajax.es6.js
@@ -4,38 +4,38 @@
  * ajax-insert-inline links for testing ajax requests.
  */
 
-(function ($, window, Drupal, drupalSettings) {
+(function ($, window, Drupal) {
   'use strict';
 
   Drupal.behaviors.insertTest = {
-    attach: function (context) {
-      $('.ajax-insert').once('ajax-insert').on('click', function (event) {
+    attach(context) {
+      $('.ajax-insert').once('ajax-insert').on('click', (event) => {
         event.preventDefault();
         const ajaxSettings = {
           url: event.currentTarget.getAttribute('href'),
           wrapper: 'ajax-target',
           base: false,
           element: false,
-          method: event.currentTarget.getAttribute('data-method')
+          method: event.currentTarget.getAttribute('data-method'),
         };
         const myAjaxObject = Drupal.ajax(ajaxSettings);
         myAjaxObject.execute();
       });
 
-      $('.ajax-insert-inline').once('ajax-insert').on('click', function (event) {
+      $('.ajax-insert-inline').once('ajax-insert').on('click', (event) => {
         event.preventDefault();
         const ajaxSettings = {
           url: event.currentTarget.getAttribute('href'),
           wrapper: 'ajax-target-inline',
           base: false,
           element: false,
-          method: event.currentTarget.getAttribute('data-method')
+          method: event.currentTarget.getAttribute('data-method'),
         };
         const myAjaxObject = Drupal.ajax(ajaxSettings);
         myAjaxObject.execute();
       });
 
       $(context).addClass('processed');
-    }
+    },
   };
-})(jQuery, window, Drupal, drupalSettings);
+})(jQuery, window, Drupal);
diff --git a/core/modules/system/tests/modules/ajax_test/js/insert-ajax.js b/core/modules/system/tests/modules/ajax_test/js/insert-ajax.js
index 4f8dba29ab..66e1b7fa7d 100644
--- a/core/modules/system/tests/modules/ajax_test/js/insert-ajax.js
+++ b/core/modules/system/tests/modules/ajax_test/js/insert-ajax.js
@@ -5,7 +5,7 @@
 * @preserve
 **/
 
-(function ($, window, Drupal, drupalSettings) {
+(function ($, window, Drupal) {
   'use strict';
 
   Drupal.behaviors.insertTest = {
@@ -39,4 +39,4 @@
       $(context).addClass('processed');
     }
   };
-})(jQuery, window, Drupal, drupalSettings);
\ No newline at end of file
+})(jQuery, window, Drupal);
\ No newline at end of file