Adding trimming sku value function to sku backend model.

app/code/Magento/Catalog/Model/Product/Attribute/Backend/Sku.php

@@ -97,6 +97,7 @@ protected function _generateUniqueSku($object)
     public function beforeSave($object)
     {
         $this->_generateUniqueSku($object);
+        $this->trimValue($object);
         return parent::beforeSave($object);
     }
 
@@ -127,4 +128,17 @@ protected function _getLastSimilarAttributeValueIncrement($attribute, $object)
         $data = $connection->fetchOne($select, $bind);
         return abs((int)str_replace($value, '', $data));
     }
+
+    /**
+     * @param Product $object
+     * @return void
+     */
+    private function trimValue($object)
+    {
+        $attrCode = $this->getAttribute()->getAttributeCode();
+        $value = $object->getData($attrCode);
+        if ($value) {
+            $object->setData($attrCode, trim($value));
+        }
+    }
 }

app/code/Magento/Catalog/Ui/DataProvider/Product/Form/Modifier/General.php

@@ -361,7 +361,8 @@ protected function customizeNameListeners(array $meta)
             $skuPath . static::META_CONFIG_PATH,
             $meta,
             [
-                'autoImportIfEmpty' => true
+                'autoImportIfEmpty' => true,
+                'validation' => ['no-marginal-whitespace' => true]
             ]
         );
 

app/code/Magento/Ui/i18n/en_US.csv

@@ -58,6 +58,7 @@ Keyword,Keyword
 "Letters, numbers, spaces or underscores only please","Letters, numbers, spaces or underscores only please"
 "Letters only please","Letters only please"
 "No white space please","No white space please"
+"No marginal white space please","No marginal white space please"
 "Your ZIP-code must be in the range 902xx-xxxx to 905-xx-xxxx","Your ZIP-code must be in the range 902xx-xxxx to 905-xx-xxxx"
 "A positive or negative non-decimal number please","A positive or negative non-decimal number please"
 "The specified vehicle identification number (VIN) is invalid.","The specified vehicle identification number (VIN) is invalid."

app/code/Magento/Ui/view/base/web/js/lib/validation/rules.js

@@ -116,6 +116,12 @@ define([
             },
             $.mage.__('No white space please')
         ],
+        'no-marginal-whitespace': [
+            function (value) {
+                return !/^\s+|\s+$/i.test(value);
+            },
+            $.mage.__('No marginal white space please')
+        ],
         'zip-range': [
             function (value) {
                 return /^90[2-5]-\d{2}-\d{4}$/.test(value);

lib/web/i18n/en_US.csv

@@ -27,6 +27,7 @@ Submit,Submit
 "Letters, numbers, spaces or underscores only please","Letters, numbers, spaces or underscores only please"
 "Letters only please","Letters only please"
 "No white space please","No white space please"
+"No marginal white space please","No marginal white space please"
 "Your ZIP-code must be in the range 902xx-xxxx to 905-xx-xxxx","Your ZIP-code must be in the range 902xx-xxxx to 905-xx-xxxx"
 "A positive or negative non-decimal number please","A positive or negative non-decimal number please"
 "The specified vehicle identification number (VIN) is invalid.","The specified vehicle identification number (VIN) is invalid."

lib/web/mage/validation.js

@@ -253,6 +253,12 @@
             },
             $.mage.__('No white space please')
         ],
+        'no-marginal-whitespace': [
+            function (value, element) {
+                return this.optional(element) || !/^\s+|\s+$/i.test(value);
+            },
+            $.mage.__('No marginal white space please')
+        ],
         'zip-range': [
             function (value, element) {
                 return this.optional(element) || /^90[2-5]-\d{2}-\d{4}$/.test(value);