Class: PluckMap::Relationships::PolymorphicOne

Inherits:
Attribute
  • Object
show all
Defined in:
lib/pluck_map/relationships/polymorphic_one.rb

Instance Attribute Summary

Attributes inherited from Attribute

#block, #id, #indexes, #model, #name, #selects, #value

Instance Method Summary collapse

Methods inherited from Attribute

#==, #apply, #eql?, #exec, #hash, #to_ruby, #value?, #values, #will_map?

Constructor Details

#initialize(attribute_name, reflection, block, options) ⇒ PolymorphicOne

Returns a new instance of PolymorphicOne.



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# File 'lib/pluck_map/relationships/polymorphic_one.rb', line 7

def initialize(attribute_name, reflection, block, options)
  @reflection = reflection
  @attributes_block = block
  @scope_block = options[:scope_block]

  options = options.slice(:as).merge(
    select: [ reflection.foreign_type.to_sym, reflection.foreign_key.to_sym ],
    map: ->(*args) { @preloads[args] })

  super(attribute_name, reflection.active_record, options)
end

Instance Method Details

#nested? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pluck_map/relationships/polymorphic_one.rb', line 19

def nested?
  true
end

#preload!(results) ⇒ Object 



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# File 'lib/pluck_map/relationships/polymorphic_one.rb', line 23

def preload!(results)
  ids_by_type = Hash.new { |hash, key| hash[key] = [] }

  results.each do |values|
    type, id = values.values_at(*indexes)
    ids_by_type[type].push(id)
  end

  @preloads = Hash.new
  ids_by_type.each do |type, ids|
    klass = type.constantize
    scope = klass.where(id: ids)
    scope = scope.instance_exec(&@scope_block) if @scope_block

    presenter = PluckMap[klass].define do |q|
      q.__id select: klass.primary_key.to_sym

      if @attributes_block.arity == 1
        @attributes_block.call(q)
      else
        q.instance_eval(&@attributes_block)
      end
    end

    presenter.to_h(scope).each do |h|
      id = h.delete(:__id)
      @preloads[[type, id]] = h
    end
  end

  nil
end