MAGETWO-54186: Problem with js validation when adding product to shopping cart

Author: iivashchenko

app/code/Magento/Catalog/view/frontend/templates/product/view/addtocart.phtml

@@ -40,6 +40,7 @@
     </div>
 </div>
 <?php endif; ?>
+<?php if ($block->isRedirectToCartEnabled()) : ?>
 <script type="text/x-magento-init">
     {
         "#product_addtocart_form": {
@@ -49,14 +50,28 @@
         }
     }
 </script>
-<?php if (!$block->isRedirectToCartEnabled()) : ?>
-<script type="text/x-magento-init">
-    {
-        "#product_addtocart_form": {
-            "catalogAddToCart": {
-                "bindSubmit": false
+<?php else : ?>
+<script>
+    require([
+        'jquery',
+        'mage/mage',
+        'Magento_Catalog/product/view/validation',
+        'Magento_Catalog/js/catalog-add-to-cart'
+    ], function ($) {
+        'use strict';
+
+        $('#product_addtocart_form').mage('validation', {
+            radioCheckboxClosest: '.nested',
+            submitHandler: function (form) {
+                var widget = $(form).catalogAddToCart({
+                    bindSubmit: false
+                });
+
+                widget.catalogAddToCart('submitForm', $(form));
+
+                return false;
             }
-        }
-    }
+        });
+    });
 </script>
 <?php endif; ?>