Prefetch subscriptions

app/controllers/question_controller.rb

@@ -4,8 +4,10 @@ class QuestionController < ApplicationController
   def show
     @question = Question.find(params[:id])
     @answers = @question.cursored_answers(last_id: params[:last_id], current_user:)
-    @answers_last_id = @answers.map(&:id).min
+    answer_ids = @answers.map(&:id)
+    @answers_last_id = answer_ids.min
     @more_data_available = !@question.cursored_answers(last_id: @answers_last_id, size: 1, current_user:).count.zero?
+    @subscribed = Subscription.where(user: current_user, answer_id: answer_ids).pluck(:answer_id) if user_signed_in?
 
     respond_to do |format|
       format.html

app/controllers/timeline_controller.rb

@@ -32,8 +32,10 @@ class TimelineController < ApplicationController
 
   def paginate_timeline
     @timeline = yield(last_id: params[:last_id])
-    @timeline_last_id = @timeline.map(&:id).min
+    timeline_ids = @timeline.map(&:id)
+    @timeline_last_id = timeline_ids.min
     @more_data_available = !yield(last_id: @timeline_last_id, size: 1).count.zero?
+    @subscribed = Subscription.where(user: current_user, answer_id: timeline_ids).pluck(:answer_id) if user_signed_in?
 
     respond_to do |format|
       format.html { render "timeline/timeline" }

app/controllers/user_controller.rb

@@ -7,9 +7,11 @@ class UserController < ApplicationController
 
   def show
     @answers = @user.cursored_answers(last_id: params[:last_id])
+    answer_ids = @answers.map(&:id)
     @pinned_answers = @user.answers.pinned.order(pinned_at: :desc).limit(10)
-    @answers_last_id = @answers.map(&:id).min
+    @answers_last_id = answer_ids.min
     @more_data_available = !@user.cursored_answers(last_id: @answers_last_id, size: 1).count.zero?
+    @subscribed = Subscription.where(user: current_user, answer_id: answer_ids).pluck(:answer_id) if user_signed_in?
 
     respond_to do |format|
       format.html

app/views/actions/_answer.html.haml

@@ -1,5 +1,5 @@
 .dropdown-menu.dropdown-menu-end{ role: :menu }
-  - if Subscription.is_subscribed(current_user, answer)
+  - if @subscribed&.include?(answer.id)
     -#                                            fun joke    should subscribe?
     %a.dropdown-item{ href: "#", data: { a_id: answer.id, action: "ab-submarine", torpedo: "no" } }
       %i.fa.fa-fw.fa-anchor