Let's read some Rails code: with

Did you know you can refactor this:

# Duplicated :dependent => :destroy option.
class Account < ActiveRecord::Base
  has_many :customers, :dependent => :destroy
  has_many :products,  :dependent => :destroy
  has_many :invoices,  :dependent => :destroy
  has_many :expenses,  :dependent => :destroy
end

into this?

# Better, perhaps.
class Account < ActiveRecord::Base
  with_options :dependent => :destroy do |assoc|
    assoc.has_many :customers
    assoc.has_many :products
    assoc.has_many :invoices
    assoc.has_many :expenses
  end
end

The with_options method is a really cool chunk of code that lets you DRY up duplication that sometimes appear when passing the same options to a series of methods.

Curious how it works behind the scenes? Check out this 11-minute code walkthrough: