delegate_to_instance

Helper for single purpose objects

Installation

Add this line to your application's Gemfile:

gem 'delegate_to_instance'

And then execute:

$ bundle

Or install it yourself as:

$ gem install delegate_to_instance

Usage

Write

class SendInvoiceJob
  extend DelegateToInstance
  delegate_to_instance :perform

  def initialize(invoice_id, recipients)
    @invoice_id, @recipients = invoice_id, recipients
  end

  def perform
    send_invoice(invoice_id, recipients)
  end
end

instead of

class SendInvoiceJob
  def self.perform(invoice_id, recipients)
    new(invoice_id, recipients).perform
  end

  def initialize(invoice_id, recipients)
    @invoice_id, @recipients = invoice_id, recipients
  end

  def perform
    send_invoice(invoice_id, recipients)
  end
end

Why

When I write single purpose objects, like

class HTMLSanitizer
  def self.sanitize(html)
    new(html).sanitize
  end

  def initialize(html)
    @html = html
  end

  def sanitize
    sanitize_html(html)
  end
end

I often find myself writing a class level delegator (and corresponding tests for it)

class HTMLSanitizer
  def self.sanitize(html)
    new(html).sanitize
  end

  # ...

Instead, just write

class HTMLSanitizer
  include DelegateToInstance
  delegate_to_instance :sanitize

  # ...

TODO

1. Add a RSpec matcher