A Rails plugin which adds a simple way of handling polymorphic associations in views, in an effort to simplify view logic
Ruby
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.
lib
README.md
Rakefile
init.rb

README.md

render :polymorphic

"Hey! Get that excess conditional logic out of that view!"

render :polymorphic is a simple plugin which adds a :polymorphic parameter to the ActionView::Base#render method. This adds an opinionated method of rendering a partial at a derived path. Useful in situations where you have views that belong to polymorphic resources.

Show Rather Than Tell:

Examples assume these associations:

class Message < ActiveRecord::Base
  belongs_to :messageable, :polymorphic => true
end

class User < ActiveRecord::Base
  has_many :messages, :as => :messageable
end

class Group < ActiveRecord::Base
  has_many :messages, :as => :messageable
end

before render :polymorphic

# in app/views/messages/index.html.erb
<%- if message.messageable.is_a?(User) %>
  # lot's of user-specific view code here
<%- elsif messageable.messageable.is_a?(Group) %>
  # lot's of group-specific view code here
<%- end %>

Personally, I despise huge blocks of conditional logic wrapping lots of view code. The above could be written a bit more nicely without using render :polymorphic as such:

# in app/views/messages/index.html.erb
<%- if message.messageable.is_a?(User) %>
  <%= render :partial => 'user_index', :locals => { :message => message } %>
<%- elsif messageable.messageable.is_a?(Group) %>
  <%= render :partial => 'group_index', :locals => { :message => message } %>
<%- end %>

But there's an abstraction to be made there, which is precisely what render :polymorphic does:

# in app/views/messages/index.html.erb
<%= render :polymorphic => message.messageable, :locals => { :message => message } %>

Which will in turn render a partial at app/views/users/messages_index.html.erb (assuming message.messageable is a User). And there we go, a neatly encapsulated pattern for getting excess conditional logic out of the view.