非同期いいね

osotmy.rb

class Ostomy < ApplicationRecord
 has_many :favorites, dependent: :destroy

def favorited_by?(staff)
  favorites.where(staff_id: staff.id).exists?
end

fovorite.rb

class Favorite < ApplicationRecord
  belongs_to :staff
  belongs_to :ostomy
end

staff.rb

class Staff < ApplicationRecord
  has_many :favorites
end

fovorite.contoroller

class Staff::FavoritesController < ApplicationController
   #医療staffが患者さん記録にいいねつける
   before_action :authenticate_staff!
  def create
    @ostomy = Ostomy.find(params[:ostomy_id])
    favorite = @ostomy.favorites.new(staff_id: current_staff.id)
    favorite.save
  end

  def destroy
    @ostomy = Ostomy.find(params[:ostomy_id])
    favorite = @ostomy.favorites.find_by(staff_id: current_staff.id)
    favorite.destroy
  end

  private
  def ostomy_params
      params.require(:ostomy).permit(:color,:edema,:skin,:h_size,:w_size,:comment,:image)
  end

end

/_fovorite.html.erb

<% if ostomy.favorited_by?(current_staff) %>
  <%= link_to staff_ostomy_favorites_path(ostomy), method: :delete,remote: true do%>
   <%= ostomy.favorites.count%>❤︎よいいね
  <%end%>
<% else %>
  <%= link_to staff_ostomy_favorites_path(ostomy), method: :post,remote: true do %>
   <%= ostomy.favorites.count%>♡︎いいね
  <%end%>
<% end %>

staff/ostomy/show.html.erb

<div class="favorite"><%= render 'staff/favorites/favorite',ostomy: @ostomy %></div>

create.js.erbとdestroy.js.erb

$(".favorite").html("<%= j(render'staff/favorites/favorite', ostomy: @ostomy) %>");