"themes": { <% unless @themes.empty? -%> <% last_index = @themes.size - 1 -%> <% @themes.each_with_index do |theme, index| -%> <%= theme.name.to_json %>: { <%= render('@theme', theme: theme) -%> }<% unless index == last_index -%>,<% end -%> <% end -%> <% end -%> },