Question

So I’m taking my first step into using Presenters for my rails app and I’m just looking at a refactoring of some of my code. I have several fields which display phone numbers (i.e. phone, cell and fax) nicely formatted or show “none given”. Obviously I originally had this in the view but moved the logic into my presenter. Once there I noticed it was all the same so refactored it into a private method which uses the method name and the send function:

class CustomerPresenter < BasePresenter
  presents :customer

  def phone
    format_number(__method__)
  end

  def cell
    format_number(__method__)
  end

  def fax
    format_number(__method__)
  end

private

  def format_number(method)
    hande_none customer.send(method) do
      h.number_to_phone(customer.send(method), :area_code => true)
    end
  end
end

and yet this code still doesn’t seem DRY. Because format_number uses the method name it seems that I have to define three seperate methods. I was curious if there was something more I could do here.

p.s. hande_none simply returns the block if there is something there or returns “none given”

Answer 1

I generally avoid to mix actual getter/method/attributes names with the methods used to format them.

That’s why I’d use *_formatted suffix: with a general suffix, you can have a simple method_missing which would lead you to something like:

class CustomerPresenter < BasePresenter
  presents :customer

  private

  def format_number(method)
    hande_none customer.send(method) do
      h.number_to_phone(customer.send(method), :area_code => true)
    end
  end

  def method_missing(method_name, *args, &block)
    case method_name
    when /(.*)_formatted$/
      #here you could create the method on the fly to avoid method missing next time
      return format_number( $1 )
    end    
    super(method_name, *args, &block)
  end
end

Basically, I’ve this in my BasePresenter for *_currency_format