Fix updating product that has no variants (#649)

* Fix updating product that has no variants

* Update changelog

CHANGELOG.md

@@ -22,6 +22,7 @@ All notable, unreleased changes to this project will be documented in this file.
 - Reset modal state after closing - #644 by @dominik-zeglen
 - Fix incorrect messages - #643 by @dominik-zeglen
 - Do not use devserver to run cypress tests - #650 by @dominik-zeglen
+- Fix updating product that has no variants - #649 by @dominik-zeglen
 
 ## 2.10.1
 

src/products/components/ProductUpdatePage/ProductUpdatePage.tsx

@@ -167,8 +167,17 @@ export const ProductUpdatePage: React.FC<ProductUpdatePageProps> = ({
   const hasVariants = maybe(() => product.productType.hasVariants, false);
 
   const handleSubmit = (data: ProductUpdatePageFormData) => {
+    if (product.productType.hasVariants) {
+      onSubmit({
+        ...data,
+        addStocks: [],
+        attributes,
+        removeStocks: [],
+        updateStocks: []
+      });
+    } else {
       const dataStocks = stocks.map(stock => stock.id);
-    const variantStocks = product.variants[0].stocks.map(
+      const variantStocks = product.variants[0]?.stocks.map(
         stock => stock.warehouse.id
       );
       const stockDiff = diff(variantStocks, dataStocks);
@@ -184,6 +193,7 @@ export const ProductUpdatePage: React.FC<ProductUpdatePageProps> = ({
           stock => !stockDiff.added.some(addedStock => addedStock === stock.id)
         )
       });
+    }
   };
 
   return (