Ruby on Rails

Passing optional local variables to a partial

Friday October 10, 2008 at 4:14am

In verbose_index.html.erb i want to pass some additional parameters to the _thing.html.erb partial:

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<% @things.each do |thing| %>
<%= render :partial => thing,
  :locals => {:some_extra_stuff => some_extra_stuff} %>
<% end %>

in index.html.erb i do not want to pass any additional parameters to the _thing.html.erb partial:

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<%= render :partial => things %>

when I hit verbose_index everything will work fine.  but when I hit index, I’ll see this error:

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undefined local variable or method 'some_extra_stuff'
  for #<ActionView::Base:0x22e6948>

to fix, in _thing.html.erb I add a check to see if the local variable is assigned:

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<% unless local_assigns[:some_extra_stuff].nil?  %>
<%= some_extra_stuff %>
<% end %>

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