CODEWITHSUNDEEP
ruby-on-railsruby
user1185081
user1185081

Reputation: 2118

Rails: How to check if content_for provided or not?

In my RoR 4.2 application, all pages provide a :title, used in the HTML header <TITLE> tag. And dynamic pages also provide a :page_heading content, which is displayed in my application header layout.

To keep a consistent look, I want the title to be also displayed in the application header layout for static pages, i.e when :page_heading is not provided.

Here is the beginning code of a show view: 

<% provide(:title, 'Managing business rules') %>
<% content_for :page_heading do %>
<h1>Business Rule: <%= @business_rule.name %></h1>
<% end %>
----

Here is the code embedded in the _header.html.erb application layout:

<h1> <%= yield(:page_heading.empty? ? :title : :page_heading) %> </h1>

So, for static pages :title is displayed in IceWeasel title bar, and in the application header as well, which is correct.

But, for dynamic pages :title is displayed in IceWeasel title bar, and also in the application header, where :page_heading is expected.

The condition on the symbol :page_heading.empty? does not work.

How can I specify this condition correctly and have the expected symbol provided to the yield function?

Thanks.

Upvotes: 1

Views: 1399

Answers (2)

Peter Brown
Peter Brown

Reputation: 51717

You can check for the content by using content_for?

<h1>
  <% if content_for? :page_heading %>
    <%= yield :page_heading %>
  <% else %>
    <%= yield :title %>
  <% end %>
</h1>

or in short:

<h1><%= yield(content_for?(:page_heading) ? :page_heading : :title) %></h1>

Upvotes: 8

Almaron
Almaron

Reputation: 4147

The answer by @Beerlington is right, I'll just add another option to DRY the code a bit.

<h1>
  <%= yield(content_for?(:page_heading)? :page_heading : :title) %>
</h1>

Upvotes: 2

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