Question

Hey guys
I’m new to rails. I made this small test code for learning helper in rails:

apps/helpers/home_helper.rb

module HomeHelper
  def show(var)
    yield var
  end
end

apps/views/home/index.html.rb

<%= show('hello world')%>

When I navigate to the url localhost:3000/home/index I got nothing in the html source
What did I do wrong?

Answer 1

There are few things to note here:

module HomeHelper
  def show(var)
    yield var
  end
end

Firstly you’re using yield which will pass control to the block given to the method. However, you then call the method without a block:

<%= show('hello world') %>

If you would have had a block it would have looked something like this:

<%= show('hello world') do |v| %>
  <%= v %>
<% end %>

This would have output ‘hello world’ as you expected.

Most like you meant:

module HomeHelper
  def show(var)
    var
  end
end

This returns the value you’re passing in and will output it to the response stream.

While block helpers can often to be useful for drying up your code most of the time you want a partial with a layout.