Question

I have a message inbox. I would like to display each message in different background based on its read status (read/not read).

My @messages variable contain multiple messages, each of which has an attribute called read_at.

My question is: how do I apply class to these items dynamically based on their read status?

Answer 1

You can do this with rails like this

<% @messages.each do |m| %>
  <div class="<%= m.read_at.nil? ? "unread" : "read" %>">
    <%= m.message_body %>
  </div>
<% end %>

Then you can set the style for read/unread messages accordingly in your css file.

In case you’re unfamiliar, this line <%= m.read_at.nil? ? "unread" : "read" %> is a ternary statement. This explains it pretty succinctly http://en.wikipedia.org/wiki/Ternary_operation#Ruby