Curryable

 What is a command object?

An object (noun) that acts as a container for a function (verb).

Design goals

• Objects should be immutable
• Object should act like a function
• Arguments to the object can be curried
• Objects should be inspectable. Inspection should reveal
  • the class
  • which arguments have been curried, and their values

class SignUpUser
  def initialize(user_creator:, attributes:, email_api:, crm_api:)
    @user_creator = user_creator
    @attributes = attributes
    @email_api = email_api
    @crm_api = crm_api
  end

  attr_reader :user_creator, :attributes, :email_api, :crm_api
  private     :user_creator, :attributes, :email_api, :crm_api

  def call
    create_user_record
    send_confirmation_email
    add_user_to_crm
  end
end

signup_service = Curryable.new(SignUpUser).call(
  user_creator: User,
  email_api: EmailAPI.new(EMAIL_AUTH_TOKEN),
  crm_api: CRMAPI.new(CRM_AUTH_TOKEN),
)

signup_service.inspect
# => <# Curryable<SignUpUser> user_creator=User, email_api=<#EmailAPI>, crm_api=<#CRMAPI>, attributes=>

signup_service.call(
  attributes: user_attrs,
)