sunkibaek · March 13, 2016 08:07
diff --git a/NullDateTime.rb b/NullDateTime.rb
 class NullDateTime
  def in_time_zone(_city = 'DefaultTimeZoneCity')
    self
  end

  def to_s(_format = :default_date_time)
    ''
  end
 end
diff --git a/order_completed.rb b/order_completed.rb
 # app/models/order.rb
 def completed?
  completed_at?
 end
diff --git a/order_completed_at.rb b/order_completed_at.rb
 # app/models/order.rb
 def completed_at
  super || NullDateTime.new
 end
diff --git a/order_show_1.rb b/order_show_1.rb
 # app/views/orders/show.html.erb
 order.completed_at.to_s(:short)
diff --git a/order_show_2.rb b/order_show_2.rb
 # app/views/orders/show.html.erb
 <% if order.completed? %>
  <%= order.completed_at.to_s(:short) %><br>
  <%= order.completed_at.in_time_zone('Seoul') %>
 <% end %>
	class NullDateTime
	def in_time_zone(_city = 'DefaultTimeZoneCity')
	self
	end

	def to_s(_format = :default_date_time)
	''
	end
	end
	# app/views/orders/show.html.erb
	order.completed_at.to_s(:short)
	# app/views/orders/show.html.erb
	<% if order.completed? %>
	<%= order.completed_at.to_s(:short) %><br>
	<%= order.completed_at.in_time_zone('Seoul') %>
	<% end %>