Class: ROM::Transformer

Inherits:
Object
  • Object
show all
Extended by:
Dry::Core::ClassAttributes
Defined in:
core/lib/rom/transformer.rb

Overview

Transformer is a data mapper which uses Transproc's transformer DSL to define transformations.

Class Method Summary collapse

Class Method Details

.build ⇒ Transformer

Build a mapper instance

Returns:



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# File 'core/lib/rom/transformer.rb', line 92

def self.build
  new
end

.map(&block) ⇒ self

Define transformation pipeline

Examples:

class UsersMapper < ROM::Transformer
  map do
    rename_keys user_id: :id
    deep_stringify_keys
  end
end

Returns:

  • (self) 


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# File 'core/lib/rom/transformer.rb', line 74

def self.map(&block)
  define! do
    map_array(&block)
  end
end

.register_as ⇒ Symbol .register_as(name) ⇒ Object

Get or set registration name

Overloads:

  • .register_as ⇒ Symbol

    Return the registration name

    Returns:

    • (Symbol)
  • .register_as(name) ⇒ Object

    Configure registration name

    Examples:

    class MyMapper < ROM::Transformer
  relation :users
  register_as :my_mapper
end

    Parameters:

    • name (Symbol) —

      The registration name



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# File 'core/lib/rom/transformer.rb', line 33

defines :register_as

.relation(name = Undefined, options = EMPTY_HASH) ⇒ Object

Configure relation for the transformer

Examples:

with a custom name

class UsersMapper < ROM::Transformer
  relation :users, as: :json_serializer

  map do
    rename_keys user_id: :id
    deep_stringify_keys
  end
end

users.map_with(:json_serializer)

Parameters:

  • name (Symbol) (defaults to: Undefined)
  • options (Hash) (defaults to: EMPTY_HASH)

Options Hash (options):

  • :as (Symbol) —

    Mapper identifier



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# File 'core/lib/rom/transformer.rb', line 54

def self.relation(name = Undefined, options = EMPTY_HASH)
  return @relation if name.equal?(Undefined) && defined?(@relation)

  register_as(options.fetch(:as, name))
  @relation = name
end