FEATURE: Allow order:votes on /filter

plugin.rb

@@ -119,6 +119,13 @@ module ::DiscourseTopicVoting
   add_to_serializer(:current_user, :votes_count) { object.vote_count }
   add_to_serializer(:current_user, :votes_left) { [object.vote_limit - object.vote_count, 0].max }
 
+  filter_order_votes = ->(scope, order_direction) do
+    scope = scope.joins(:topic_vote_count)
+    scope.order("topic_voting_topic_vote_count.votes_count #{order_direction}")
+  end
+
+  add_filter_custom_filter("order:votes", &filter_order_votes)
+
   on(:topic_status_updated) do |topic, status, enabled|
     next if topic.trashed?
     next if %w[closed autoclosed archived].exclude?(status)

spec/lib/topics_filter_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+RSpec.describe TopicsFilter do
+  describe "when extending order:{col}" do
+    fab!(:topic_high) { Fabricate(:topic_voting_vote_count, votes_count: 10).topic }
+    fab!(:topic_med) { Fabricate(:topic_voting_vote_count, votes_count: 5).topic }
+    fab!(:topic_low) { Fabricate(:topic_voting_vote_count, votes_count: 1).topic }
+
+    it "sorts votes in ascending order" do
+      expect(
+        TopicsFilter
+          .new(guardian: Guardian.new)
+          .filter_from_query_string("order:votes-asc")
+          .pluck(:id),
+      ).to eq([topic_low.id, topic_med.id, topic_high.id])
+    end
+
+    it "sorts votes in default descending order" do
+      expect(
+        TopicsFilter.new(guardian: Guardian.new).filter_from_query_string("order:votes").pluck(:id),
+      ).to eq([topic_high.id, topic_med.id, topic_low.id])
+    end
+  end
+end