Rails check if yield :area is defined in content_for

@content_for_whatever is deprecated.Use content_for? instead, like this:

<% if content_for?(:whatever) %>  <div><%= yield(:whatever) %></div><% end %>

ruby-on-rails layout yield

not really necessary to create a helper method:

<% if @content_for_sidebar %>  <div id="sidebar">    <%= yield :sidebar %>  </div><% end %>

then of course in your view:

<% content_for :sidebar do %>  ...<% end %>

I use this all the time to conditionally go between a one column and two column layout

ruby-on-rails layout yield

<%if content_for?(:content)%>  <%= yield(:content) %><%end%>

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