Add ability to sort on multiple fields

CHANGELOG.md

@@ -2,7 +2,7 @@ CHANGELOG
 ---------
 
 - **Unreleased - [View Diff](https://github.com/westonganger/active_sort_order/compare/v0.9.2...master)**
-  * Nothing yet
+  * Allow ability to sort on multiple fields
 
 - **v0.9.2 - Apr 28, 2021 - [View Diff](https://github.com/westonganger/active_sort_order/compare/v0.9.1...v0.9.2)**
   * Fix deprecation warning in Rails 6.1 for `reorder(nil)`

README.md

@@ -36,8 +36,12 @@ In the below examples we are within a controller and are using the params as our
 ```ruby
 # app/controllers/posts_controller.rb
 
-if params[:sort] == "number_str"
+case params[:sort]
+when "number_str"
   sort_col_sql = "CAST(posts.number_str AS int)"
+when "user"
+  ### To sort on multiple fields pass in an Array
+  sort_col_sql = ["users.first_name", "users.last_name"] 
 else
   sort_col_sql = params[:sort]
 end
@@ -49,6 +53,8 @@ Post.all.sort_order(sort_col_sql, params[:direction], base_sort_order: "lower(nu
 Post.all.sort_order(sort_col_sql, params[:direction]) 
 ```
 
+## Sorting on multiple columns
+
 ##### Method Definition:
 
 `sort_order(sort_col_sql = nil, sort_direction_sql = nil, base_sort_order: true)`

lib/active_sort_order/concerns/sort_order_concern.rb

@@ -5,12 +5,12 @@ module SortOrderConcern
     included do
 
       scope :sort_order, ->(sort_col_sql = nil, sort_direction_sql = nil, base_sort_order: true){
-        if [String, Symbol, NilClass].exclude?(sort_col_sql.class)
-          raise ArgumentError.new("Invalid first argument `sort_col_sql`, expecting a a String or Symbol")
-        end
-
         if sort_col_sql.present?
-          sort_col_sql = sort_col_sql.to_s
+          if sort_col_sql.is_a?(Array)
+            sort_col_sql = sort_col_sql.map{|x| x.to_s }
+          else
+            sort_col_sql = sort_col_sql.to_s
+          end
 
           ### SORT DIRECTION HANDLING
           if sort_direction_sql.is_a?(Symbol)
@@ -20,7 +20,7 @@ module SortOrderConcern
           if sort_direction_sql.nil? || (sort_direction_sql.is_a?(String) && sort_direction_sql == "")
             sort_direction_sql = "ASC"
           elsif !sort_direction_sql.is_a?(String)
-            raise ArgumentError.new("Invalid second argument `sort_direction_sql`, expecting a a String or Symbol")
+            raise ArgumentError.new("Invalid second argument `sort_direction_sql`, expecting a String or Symbol")
           else
             valid_directions = [
               "ASC",
@@ -41,7 +41,11 @@ module SortOrderConcern
             end
           end
 
-          sql_str = "#{sort_col_sql} #{sort_direction_sql}"
+          if !sort_col_sql.is_a?(Array)
+            sort_col_sql = [sort_col_sql]
+          end
+
+          sql_str = sort_col_sql.map{|x| "#{x} #{sort_direction_sql}" }.join(", ")
         end
 
         ### BASE SORT ORDER HANDLING

test/unit/active_sort_order_test.rb

@@ -121,4 +121,24 @@ def test_base_sort_order_and_sort
     end
   end
 
+  def test_sort_on_multiple_fields
+    assert_equal Post.all.count, DATA[:posts].count
+
+    expected = DATA[:posts].sort_by{|item| [item.b, item.a] }
+
+    sorted = PostWithBaseOrderA.all.sort_order([:b, :a], :asc)
+
+    sorted.each_with_index do |item, i|
+      assert_equal expected[i].id, item.id
+    end
+
+    expected = DATA[:posts].sort_by{|item| [item.b, item.a] }.reverse
+
+    sorted = PostWithBaseOrderA.all.sort_order([:b, :a], :desc)
+
+    sorted.each_with_index do |item, i|
+      assert_equal expected[i].id, item.id
+    end
+  end
+
 end