Add :in_stock, :stock_location_id, :stock_location_name to admin variant serializer, these are needed for the variant_autocomplete js code from spree

app/serializers/api/admin/variant_serializer.rb

@@ -1,6 +1,9 @@
 class Api::Admin::VariantSerializer < ActiveModel::Serializer
-  attributes :id, :options_text, :unit_value, :unit_description, :unit_to_display, :on_demand, :display_as, :display_name, :name_to_display, :sku
-  attributes :on_hand, :price, :import_date, :name, :producer_name, :image
+  attributes :id, :name, :producer_name, :image, :sku, :import_date
+  attributes :options_text, :unit_value, :unit_description, :unit_to_display
+  attributes :display_as, :display_name, :name_to_display
+  attributes :price, :on_demand, :on_hand, :in_stock, :stock_location_id, :stock_location_name
+
   has_many :variant_overrides
 
   def name
@@ -17,7 +20,7 @@ class Api::Admin::VariantSerializer < ActiveModel::Serializer
   end
 
   def price
-    # Decimals are passed to json as strings, we need to run parseFloat.toFixed(2) on the client side.
+    # Decimals are passed to json as strings, we need to run parseFloat.toFixed(2) on the client.
     object.price.nil? ? 0.to_f : object.price
   end
 
@@ -26,6 +29,21 @@ class Api::Admin::VariantSerializer < ActiveModel::Serializer
   end
 
   def image
+    return if object.product.images.empty?
     object.product.images.first.mini_url
   end
+
+  def in_stock
+    object.in_stock?
+  end
+
+  def stock_location_id
+    return if object.stock_items.empty?
+    object.stock_items.first.stock_location.id
+  end
+
+  def stock_location_name
+    return if object.stock_items.empty?
+    object.stock_items.first.stock_location.name
+  end
 end