When you setup a new Rails project, you’ll have a single layout file which has a single default
yield block. This will soon be inadequate, and you’ll want another. Here’s how to setup multiple
yield blocks per ERB template.
By default, Rails will create a file at:
In this file, there will be a default
yield block similar to this:
<%= yield %>
It has no name. It’s just the default place for templates that use this layout file to put their content.
We can create new
yield blocks. We’ll have to give them a distinguishing name. They look about the same. If I wanted to create a new
yield block where, for instance, alerts could be displayed if the child template had them, I could put this in my layout file:
<%= yield(:alert) %>
Now I would just need something to go in it.
A child template that uses the
application.html.erb layout file can just start blasting out markup that will go into the default
yield block. This will usually be the main content. But in our example, there might be more focused content such as alerts that we want to display in a separate area. Thus, our template could potentially look like this:
<h1>My main content</h1> <p>Bacon ipsum…<p> <% content_for :alert do %> <div class="alert alert-success"> You created multiple yield blocks! </div> <% end %>
Throw down a
content_for block, matching the name of the
yield block in your layout file, and you’re set. Order does not matter. Your specific
content_for blocks can come before, after, or in the middle of your main content. Easy as Ruby pie.