Rails: An elegant way to display a message when there are no elements in database

Question

I realized that I\'m writing a lot of code similar to this one:

<% unless @messages.blank? %>
  <% @messages.each do |message|  %>
    <%# cod         


        

Answer 1

You can create some custom helper. The following one is just an example.

# application_helper.html.erb
def unless_empty(collection, message = "You have no messages", &block)
  if collection.empty?
    concat(message)
  else
    concat(capture(&block))
  end
end

# view.html.erb
<% unless_empty @messages do %>
  <%# code or partial to dispaly the message %>
<% end %>

Answer 2

I'm surprised my favorite answer isn't up here. There is an answer thats close, but I don't like bare text and using content_for is klunky. Try this one on for size:

  <%= render(@user.recipes) || content_tag("p") do %>
    This user hasn't added any recipes yet!
  <% end %>

Answer 3

You could also write something like this:

<% if @messages.each do |message| %>
  <%# code or partial to display the message %>
<% end.empty? %>
  You have no messages.
<% end %>

Answer 4

That code can be shortened to:

<%= @messages.empty? ? 'You have no messages.' : @messages.collect { |msg| formatted_msg(msg) }.join(msg_delimiter) %>

Comments:

formatted_msg() - helper method which adds formatting to the message

msg_delimiter - variable containing delimiter like "\n" or "<br />"

BTW I'd suggest to use empty? method instead of blank? for checking an array, because a) its name is more concise :) and b) blank? is an ActiveSupport extension method which won't work outside Rails.

Answer 5

One way is to do something like:

<%= render(:partial => @messages) || render('no_messages') %>

Edit:

If I remember correctly this was made possible by this commit:

http://github.com/rails/rails/commit/a8ece12fe2ac7838407954453e0d31af6186a5db

Answer 6

Old topic but I didn't really like any of these so playing around on Rails 3.2 I figured out this alternative:

<% content_for :no_messages do %>
  <p>
    <strong>No Messages Found</strong>
  </p>
<% end %>

<%= render @messages || content_for(:no_messages) %>

Or if you need a more verbose render with partial path like I did:

<%= render(:partial => 'messages', 
     :collection => @user.messages) || content_for(:no_messages) %>

This way you can style the "no messages" part with whatever HTML / view logic you want and keep it nice a easy to read.