diff --git a/core/misc/ajax.es6.js b/core/misc/ajax.es6.js
index d8fe6e8783..421c0edd70 100644
--- a/core/misc/ajax.es6.js
+++ b/core/misc/ajax.es6.js
@@ -990,19 +990,15 @@
    *   The response from the Ajax request.
    */
   Drupal.theme.ajaxWrapperNewContent = ($newContent, ajax, response) => {
-    let typeEffect = response.effect || ajax.effect;
-    if ($newContent.length > 1 && typeEffect !== 'none') {
-      let countEffectElements = $newContent.length;
-      // Exclude all nodes not participating in the animation effect.
-      for (let i = 0; i < $newContent.length; i++) {
-        if (
-          ($newContent[i].nodeName === '#comment') ||
-          ($newContent[i].nodeName === '#text' && /^(\s|\n|\r)*$/.test($newContent[i].textContent))
-        ) {
-          countEffectElements--;
-        }
-      }
-      if (countEffectElements > 1) {
+    const typeEffect = response.effect || ajax.effect;
+    if (typeEffect !== 'none') {
+      // Exclude all nodes that do not interfere with animation effect.
+      const $filteredContent = $newContent.filter(function(i) {
+        let isHtmlComment = $newContent[i].nodeName !== '#comment';
+        let isWhitespaceText = $newContent[i].nodeName === '#text' && /^(\s|\n|\r)*$/.test($newContent[i].textContent);
+        return !(isHtmlComment || isWhitespaceText);
+      });
+      if ($filteredContent.length > 1) {
         $newContent = Drupal.theme('ajaxWrapperMultipleRootElements', $newContent);
       }
     }
diff --git a/core/misc/ajax.js b/core/misc/ajax.js
index d614a61d0a..fb2ee0f680 100644
--- a/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -480,15 +480,13 @@ function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr
 
   Drupal.theme.ajaxWrapperNewContent = function ($newContent, ajax, response) {
     var typeEffect = response.effect || ajax.effect;
-    if ($newContent.length > 1 && typeEffect !== 'none') {
-      var countEffectElements = $newContent.length;
-
-      for (var i = 0; i < $newContent.length; i++) {
-        if ($newContent[i].nodeName === '#comment' || $newContent[i].nodeName === '#text' && /^(\s|\n|\r)*$/.test($newContent[i].textContent)) {
-          countEffectElements--;
-        }
-      }
-      if (countEffectElements > 1) {
+    if (typeEffect !== 'none') {
+      var $filteredContent = $newContent.filter(function (i) {
+        var isHtmlComment = $newContent[i].nodeName !== '#comment';
+        var isWhitespaceText = $newContent[i].nodeName === '#text' && /^(\s|\n|\r)*$/.test($newContent[i].textContent);
+        return !(isHtmlComment || isWhitespaceText);
+      });
+      if ($filteredContent.length > 1) {
         $newContent = Drupal.theme('ajaxWrapperMultipleRootElements', $newContent);
       }
     }
diff --git a/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxTest.php b/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxTest.php
index 7a63551c36..b1dd8ca823 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxTest.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxTest.php
@@ -4,7 +4,6 @@
 
 use Drupal\FunctionalJavascriptTests\DrupalSelenium2Driver;
 use Drupal\FunctionalJavascriptTests\JavascriptTestBase;
-use Drupal\FunctionalJavascriptTests\JSWebAssert;
 
 /**
  * Tests AJAX responses.