4 Simple Memoization Patterns in Ruby (and One Gem)

28 August 2016

http://www.justinweiss.com/articles/4-simple-memoization-patterns-in-ruby-and-one-gem/

Super basic memoization

class User < ActiveRecord::Base
  def twitter_followers
    # assuming twitter_user.followers makes a network call
    @twitter_followers ||= twitter_user.followers
  end
end

Multi-line memoization

class User < ActiveRecord::Base
  def main_address
    @main_address ||= begin
      maybe_main_address = home_address if prefers_home_address?
      maybe_main_address = work_address unless maybe_main_address
      maybe_main_address = addresses.first unless maybe_main_address
    end
  end
end

Gem Memoist: https://github.com/matthewrudy/memoist