Include sort direction parameter during bulk product update to prevent JS error causing 'Saving' text to hang

Before if you did a bulk product update there was an error:

> TypeError: Cannot set property 'variants' of null

It only seemed to happen if pagination was required i.e. more than 15 products. It seemed to be happening because the default sort order on the products API endpoint which handles the bulk update is 'created desc' but 'name asc' on the /admin/products controller.

Another fix included here is for the sorting direction arrows which were not displaying on the admin products page. The sorting arrows require the sorting expression to be on the :sorting var instead of :q.sorting.

Fixes #6399

app/assets/javascripts/admin/bulk_product_update.js.coffee

@@ -21,6 +21,7 @@ angular.module("ofn.admin").controller "AdminProductEditCtrl", ($scope, $timeout
     sorting: ""
   }
 
+  $scope.sorting = "name asc"
   $scope.producers = producers
   $scope.taxons = Taxons.all
   $scope.tax_categories = tax_categories
@@ -48,7 +49,7 @@ angular.module("ofn.admin").controller "AdminProductEditCtrl", ($scope, $timeout
       'q[name_cont]': $scope.q.query,
       'q[supplier_id_eq]': $scope.q.producerFilter,
       'q[primary_taxon_id_eq]': $scope.q.categoryFilter,
-      'q[s]': $scope.q.sorting,
+      'q[s]': $scope.sorting,
       import_date: $scope.q.importDateFilter,
       page: $scope.page,
       per_page: $scope.per_page
@@ -104,7 +105,7 @@ angular.module("ofn.admin").controller "AdminProductEditCtrl", ($scope, $timeout
   $scope.$watch 'sortOptions', (sort) ->
     return unless sort && sort.predicate != ""
 
-    $scope.q.sorting = sort.getSortingExpr()
+    $scope.sorting = sort.getSortingExpr(defaultDirection: "asc")
     $scope.fetchProducts()
   , true
 
@@ -216,6 +217,7 @@ angular.module("ofn.admin").controller "AdminProductEditCtrl", ($scope, $timeout
           'q[name_cont]': $scope.q.query
           'q[supplier_id_eq]': $scope.q.producerFilter
           'q[primary_taxon_id_eq]': $scope.q.categoryFilter
+          'q[s]': $scope.sorting
           import_date: $scope.q.importDateFilter
         page: $scope.page
         per_page: $scope.per_page

app/assets/javascripts/admin/index_utils/services/sort_options.js.coffee

@@ -3,9 +3,11 @@ angular.module("admin.indexUtils").factory 'SortOptions', ->
     predicate: ""
     reverse: true
 
-    getSortingExpr: () ->
-      sortingExpr = this.predicate + ' desc' if this.reverse
-      sortingExpr = this.predicate + ' asc' if !this.reverse
+    getSortingExpr: (options) ->
+      defaultDirection = if (options && options.defaultDirection) then options.defaultDirection else "desc"
+      reverseDirection = if defaultDirection == "desc" then "asc" else "desc"
+      sortingExpr = this.predicate + ' ' + defaultDirection if this.reverse
+      sortingExpr = this.predicate + ' ' + reverseDirection if !this.reverse
       sortingExpr
 
     toggle: (predicate) ->

spec/javascripts/unit/admin/bulk_product_update_spec.js.coffee

@@ -368,7 +368,7 @@ describe "AdminProductEditCtrl", ->
       $scope.sortOptions.toggle('name')
       $scope.$apply()
 
-      expect($scope.q.sorting).toEqual 'name asc'
+      expect($scope.sorting).toEqual 'name desc'
       expect($scope.fetchProducts).toHaveBeenCalled()
 
   describe "updating the product on hand count", ->

spec/javascripts/unit/admin/index_utils/services/sort_options_spec.js.coffee

@@ -42,3 +42,19 @@ describe "SortOptions service", ->
         SortOptions.toggle("column.b")
         expect(SortOptions.predicate).toEqual "column.b"
         expect(SortOptions.reverse).toBe false
+
+    describe "getting the sorting expression", ->
+      describe "when not specifying the default sort direction", ->
+        it "sets the direction to 'asc' after the first toggle because the default direction is 'desc'", ->
+          SortOptions.toggle("column.a")
+          expect(SortOptions.getSortingExpr()).toEqual "column.a asc"
+
+      describe "when specifying the default sorting direction as 'desc'", ->
+        it "sets the direction to 'asc' after the first toggle", ->
+          SortOptions.toggle("column.a")
+          expect(SortOptions.getSortingExpr(defaultDirection: "desc")).toEqual "column.a asc"
+
+      describe "when specifying the default sorting direction as 'asc'", ->
+        it "sets the direction to 'desc' after the first toggle", ->
+          SortOptions.toggle("column.a")
+          expect(SortOptions.getSortingExpr(defaultDirection: "asc")).toEqual "column.a desc"