Use subqueries to check reaction/subscription state

app/controllers/answer_controller.rb

@@ -8,15 +8,11 @@ class AnswerController < ApplicationController
   turbo_stream_actions :pin, :unpin
 
   def show
-    @answer = Answer.includes(question: [:user], smiles: [:user]).find(params[:id])
+    @answer = Answer.for_user(current_user).includes(question: [:user], smiles: [:user]).find(params[:id])
     @display_all = true
-    @reacted_answer_ids = []
-    @subscribed_answer_ids = []
 
     return unless user_signed_in?
 
-    @reacted_answer_ids = Reaction.where(user: current_user, parent: @answer).pluck(:parent_id)
-    @subscribed_answer_ids = Subscription.where(user: current_user, answer: @answer).pluck(:answer_id)
     mark_notifications_as_read
   end
 

app/controllers/concerns/paginates_answers.rb

@@ -5,12 +5,6 @@ module PaginatesAnswers
     @answers = yield(last_id: params[:last_id])
     answer_ids = @answers.map(&:id)
     @answers_last_id = answer_ids.min
-    answer_ids += @pinned_answers.pluck(:id) if @pinned_answers.present?
+    @more_data_available = !yield(last_id: @answers_last_id, size: 1).select("answers.id").count.zero?
-    @more_data_available = !yield(last_id: @answers_last_id, size: 1).count.zero?
-
-    return unless user_signed_in?
-
-    @reacted_answer_ids = Reaction.where(user: current_user, parent_type: "Answer", parent_id: answer_ids).pluck(:parent_id)
-    @subscribed_answer_ids = Subscription.where(user: current_user, answer_id: answer_ids).pluck(:answer_id)
   end
 end

app/controllers/discover_controller.rb

@@ -8,15 +8,11 @@ class DiscoverController < ApplicationController
 
     top_x = 10  # only display the top X items
 
-    @popular_answers = Answer.where("created_at > ?", Time.now.ago(1.week)).order(:smile_count).reverse_order.limit(top_x).includes(:question, :user, :comments)
+    @popular_answers = Answer.for_user(current_user).where("created_at > ?", Time.now.ago(1.week)).order(:smile_count).reverse_order.limit(top_x).includes(:question, :user, :comments)
-    @most_discussed = Answer.where("created_at > ?", Time.now.ago(1.week)).order(:comment_count).reverse_order.limit(top_x).includes(:question, :user, :comments)
+    @most_discussed = Answer.for_user(current_user).where("created_at > ?", Time.now.ago(1.week)).order(:comment_count).reverse_order.limit(top_x).includes(:question, :user, :comments)
     @popular_questions = Question.where("created_at > ?", Time.now.ago(1.week)).order(:answer_count).reverse_order.limit(top_x).includes(:user)
     @new_users = User.where("asked_count > 0").order(:id).reverse_order.limit(top_x).includes(:profile)
 
-    answer_ids = @popular_answers.map(&:id) + @most_discussed.map(&:id)
-    @reacted_answer_ids = Reaction.where(user: current_user, parent_type: "Answer", parent_id: answer_ids).pluck(:parent_id)
-    @subscribed_answer_ids = Subscription.where(user: current_user, answer_id: answer_ids).pluck(:answer_id)
-
     # .user = the user
     # .question_count = how many questions did the user ask
     @users_with_most_questions = Question.select('user_id, COUNT(*) AS question_count').

app/controllers/question_controller.rb

@@ -8,8 +8,7 @@ class QuestionController < ApplicationController
     @answers = @question.cursored_answers(last_id: params[:last_id], current_user:)
     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?
+    @more_data_available = !@question.cursored_answers(last_id: @answers_last_id, size: 1, current_user:).select("answers.id").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

@@ -32,11 +32,9 @@ class TimelineController < ApplicationController
 
   def paginate_timeline
     @timeline = yield(last_id: params[:last_id])
-    timeline_ids = @timeline.map(&:id)
+    timeline_ids = @timeline.select("answers.id").map(&:id)
     @timeline_last_id = timeline_ids.min
-    @more_data_available = !yield(last_id: @timeline_last_id, size: 1).count.zero?
+    @more_data_available = !yield(last_id: @timeline_last_id, size: 1).select("answers.id").count.zero?
-    @reacted_answer_ids = Reaction.where(user: current_user, parent_type: "Answer", parent_id: timeline_ids).pluck(:parent_id)
-    @subscribed_answer_ids = Subscription.where(user: current_user, answer_id: timeline_ids).pluck(:answer_id)
 
     respond_to do |format|
       format.html { render "timeline/timeline" }

app/controllers/user_controller.rb

@@ -8,8 +8,8 @@ class UserController < ApplicationController
   after_action :mark_notification_as_read, only: %i[show]
 
   def show
-    @pinned_answers = @user.answers.pinned.includes([{ user: :profile }, :question]).order(pinned_at: :desc).limit(10).load_async
+    @pinned_answers = @user.answers.for_user(current_user).pinned.includes([{ user: :profile }, :question]).order(pinned_at: :desc).limit(10).load_async
-    paginate_answers { |args| @user.cursored_answers(**args) }
+    paginate_answers { |args| @user.cursored_answers(current_user_id: current_user, **args) }
 
     respond_to do |format|
       format.html

app/models/answer.rb

@@ -15,6 +15,20 @@ class Answer < ApplicationRecord
   # rubocop:enable Rails/UniqueValidationWithoutIndex
 
   scope :pinned, -> { where.not(pinned_at: nil) }
+  scope :for_user, lambda { |current_user|
+    next select("answers.*", "false as is_subscribed", "false as has_reacted") if current_user.nil?
+
+    select("answers.*",
+           "EXISTS(SELECT 1
+              FROM subscriptions
+              WHERE answer_id = answers.id
+                AND user_id = #{current_user.id}) as is_subscribed",
+           "EXISTS(SELECT 1
+              FROM reactions
+              WHERE parent_id = answers.id
+                AND parent_type = 'Answer'
+                AND user_id = #{current_user.id}) as has_reacted")
+  }
 
   SHORT_ANSWER_MAX_LENGTH = 640
 

app/models/answer/timeline_methods.rb

@@ -6,7 +6,8 @@ module Answer::TimelineMethods
   define_cursor_paginator :cursored_public_timeline, :public_timeline
 
   def public_timeline(current_user: nil)
-    includes([{ user: :profile }, :question])
+    for_user(current_user)
+      .includes([{ user: :profile }, :question])
       .then do |query|
         next query unless current_user
 

app/models/list/timeline_methods.rb

@@ -8,6 +8,7 @@ module List::TimelineMethods
   # @return [ActiveRecord::Relation<Answer>] the lists' timeline
   def timeline(current_user: nil)
     Answer
+      .for_user(current_user)
       .includes([{ user: :profile }, :question])
       .then do |query|
         next query unless current_user

app/models/question/answer_methods.rb

@@ -7,6 +7,7 @@ module Question::AnswerMethods
 
   def ordered_answers(current_user: nil)
     answers
+      .for_user(current_user)
       .includes([{ user: :profile }, :question])
       .then do |query|
         next query unless current_user

app/models/user/answer_methods.rb

@@ -6,8 +6,9 @@ module User::AnswerMethods
   define_cursor_paginator :cursored_answers, :ordered_answers
 
   # @return [ActiveRecord::Relation<Answer>] List of a user's answers
-  def ordered_answers
+  def ordered_answers(current_user_id:)
     answers
+      .for_user(current_user_id)
       .order(:created_at)
       .reverse_order
       .includes(question: { user: [:profile] })

app/models/user/timeline_methods.rb

@@ -8,6 +8,7 @@ module User::TimelineMethods
   # @return [ActiveRecord::Relation<Answer>] the user's timeline
   def timeline
     Answer
+      .for_user(self)
       .then do |query|
         blocked_and_muted_user_ids = blocked_user_ids_cached + muted_user_ids_cached
         next query if blocked_and_muted_user_ids.empty?

app/views/actions/_answer.html.haml

@@ -1,5 +1,5 @@
 .dropdown-menu.dropdown-menu-end{ role: :menu }
-  - if subscribed_answer_ids&.include?(answer.id)
+  - if answer.is_subscribed
     = render "subscriptions/destroy", answer: answer
   - else
     = render "subscriptions/create", answer: answer

app/views/answer/show.html.haml

@@ -1,4 +1,4 @@
 - provide(:title, answer_title(@answer))
 - provide(:og, answer_opengraph(@answer))
 .container-lg.container--main
-  = render "answerbox", a: @answer, display_all: @display_all, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+  = render "answerbox", a: @answer, display_all: @display_all

app/views/answerbox/_actions.html.haml

@@ -1,4 +1,4 @@
-%button.btn.btn-link.answerbox__action{ type: :button, name: "ab-smile", data: { a_id: a.id, action: reacted_answer_ids&.include?(a.id) ? :unsmile : :smile, selection_hotkey: "s" }, disabled: !user_signed_in? }
+%button.btn.btn-link.answerbox__action{ type: :button, name: "ab-smile", data: { a_id: a.id, action: a.has_reacted ? :unsmile : :smile, selection_hotkey: "s" }, disabled: !user_signed_in? }
   %i.fa.fa-fw.fa-smile-o
   %span{ id: "ab-smile-count-#{a.id}" }= a.smile_count
 - unless display_all
@@ -13,4 +13,4 @@
   .btn-group
     %button.btn.btn-default.btn-sm.dropdown-toggle{ data: { bs_toggle: :dropdown }, aria: { expanded: false } }
       %span.caret
-    = render "actions/answer", answer: a, subscribed_answer_ids:
+    = render "actions/answer", answer: a

app/views/application/_answerbox.html.haml

@@ -22,7 +22,7 @@
               .answerbox__answer-date
                 = link_to(raw(t("time.distance_ago", time: time_tooltip(a))), answer_path(a.user.screen_name, a.id), data: { selection_hotkey: "l" })
         .col-md-6.d-flex.d-md-block.answerbox__actions
-          = render "answerbox/actions", a:, display_all:, subscribed_answer_ids:, reacted_answer_ids:
+          = render "answerbox/actions", a:, display_all:
     - else
       .row
         .col-md-6.text-start.text-muted
@@ -34,7 +34,7 @@
               %i.fa.fa-thumbtack
               = t(".pinned")
         .col-md-6.d-md-flex.answerbox__actions
-          = render "answerbox/actions", a:, display_all:, subscribed_answer_ids:, reacted_answer_ids:
+          = render "answerbox/actions", a:, display_all:
   .card-footer{ id: "ab-comments-section-#{a.id}", class: display_all.nil? ? "d-none" : nil }
     = turbo_frame_tag("ab-reactions-list-#{a.id}", src: reactions_path(a.question, a), loading: :lazy) do
       .d-flex.smiles

app/views/discover/tab/_answers.html.haml

@@ -1,3 +1,3 @@
 .tab-pane.active.fade.show{ role: :tabpanel, id: "answers" }
   - answers.each do |a|
-    = render "answerbox", a:, subscribed_answer_ids:, reacted_answer_ids:
+    = render "answerbox", a:

app/views/discover/tab/_discussed.html.haml

@@ -1,3 +1,3 @@
 .tab-pane.fade{ role: :tabpanel, id: "comments" }
   - comments.each do |a|
-    = render "answerbox", a:, subscribed_answer_ids:, reacted_answer_ids:
+    = render "answerbox", a:

app/views/question/show.html.haml

@@ -8,7 +8,7 @@
     %button.d-none{ data: { hotkey: "j", action: "navigation#down" } }
     %button.d-none{ data: { hotkey: "k", action: "navigation#up" } }
     - @answers.each do |a|
-      = render "answerbox", a:, show_question: false, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+      = render "answerbox", a:, show_question: false
 
   - if @more_data_available
     .d-flex.justify-content-center.justify-content-sm-start#paginator

app/views/question/show.turbo_stream.haml

@@ -1,6 +1,6 @@
 = turbo_stream.append "answers" do
   - @answers.each do |a|
-    = render "answerbox", a:, show_question: false, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+    = render "answerbox", a:, show_question: false
 
 = turbo_stream.update "paginator" do
   - if @more_data_available

app/views/timeline/timeline.html.haml

@@ -2,7 +2,7 @@
   %button.d-none{ data: { hotkey: "j", action: "navigation#down" } }
   %button.d-none{ data: { hotkey: "k", action: "navigation#up" } }
   - @timeline.each do |answer|
-    = render "answerbox", a: answer, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+    = render "answerbox", a: answer
 
 - if @more_data_available
   .d-flex.justify-content-center#paginator

app/views/timeline/timeline.turbo_stream.haml

@@ -1,6 +1,6 @@
 = turbo_stream.append "timeline" do
   - @timeline.each do |answer|
-    = render "answerbox", a: answer, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+    = render "answerbox", a: answer
 
 = turbo_stream.update "paginator" do
   - if @more_data_available

app/views/user/show.html.haml

@@ -4,11 +4,11 @@
     %button.d-none{ data: { hotkey: "k", action: "navigation#up" } }
     #pinned-answers
       - @pinned_answers.each do |a|
-        = render "answerbox", a:, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+        = render "answerbox", a:
 
     #answers
       - @answers.each do |a|
-        = render "answerbox", a:, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+        = render "answerbox", a:
 
 - if @more_data_available
   .d-flex.justify-content-center.justify-content-sm-start#paginator

app/views/user/show.turbo_stream.haml

@@ -1,6 +1,6 @@
 = turbo_stream.append "answers" do
   - @answers.each do |a|
-    = render "answerbox", a:, subscribed_answer_ids: @subscribed_answer_ids, reacted_answer_ids: @reacted_answer_ids
+    = render "answerbox", a:
 
 = turbo_stream.update "paginator" do
   - if @more_data_available