Refactoring towards decorators in Rails

Decorators

They wrap an object and extend its functionality without modifying the object itself.

The problem

Say you have the following view.

 <p>Name: <%= @company.name.titleize %></p>

 <p>Email: <%= @company.email_private? 'Private' : @company.email %></p>

 <p>Sign Up At: <%= @company.sign_up_at.strftime('%d. %m. %Y.') %></p>

It's bad because the view should not care about how to display the data, it should just display it.

The Decorator object

class CompanyDecorator < SimpleDelegator
  def display_name
    name.titleize
  end

  def protected_email
    return "Private" if email_private?
    email
  end

  def formatted_sign_up_at
    sign_up_at.strftime("%d %b %Y")
  end
end

The implementation

Nice, let's see how the controller looks now.

class CompanyController < ApplicationController
  def show
    company = Company.find(params[:id])
    @decorated_company = CompanyDecorator.new(company)
  end
end

Now, the view

 <p>Name: <%= @decorated_company.display_name %></p>

 <p>Email: <%= @decorated_company.protected_email %></p>

 <p>Birthday: <%= @decorated_company.formatted_sign_up_at %></p>

Final thoughts

Not only looks better, testing this approach is much simpler.

This does not only applies for Rails apps, this pattern could be used anywhere in Ruby.

Comments

[Fernando Maia]

Nice and clean solution. Awesome!