Array#reactiverecordize

array_reactiverecordize.rb

# array_reactiverecordize_spec.rb

require 'spec_helper'

describe "Array#reactiverecordize" do

  let!(:john_doe)  { create(:user, first_name: "John", last_name: "Doe",  birth_year: '1966')}
  let!(:mike_pike) { create(:user, first_name: "Mike", last_name: "Pike", birth_year: '1996')}
  let!(:carl_doe)  { create(:user, first_name: "Carl", last_name: "Doe",  birth_year: '1926')}

  subject { User.where(last_name: 'Doe').select { |u| u.birth_year == 1926} }
  specify { expect(subject).to be_an Array }
  specify { expect(subject).to include(carl_doe) }

  # this raises undefined method `where' for []:Array
  specify { expect{subject.where(first_name: "Carl")}.to raise_error }
  
  # but this works
  specify { expect(subject.reactiverecordize.where(first_name: "Carl")).to include(carl_doe) }
end

# lib/core_ext/array.rb
class Array
  def reactiverecordize
    class_of_first = self[0].class
    ids = self.map(&:id)
    class_of_first.where(id: ids)
  end
end

This is a fix for a situation that arises when you try to chain active_record scopes and in-memory operations like selects, array intersection/join, and so on.

It tries to convert an array back to an ActiveRecord scope by refiltering on ids.

The code inside Array#reactiverecordize is just a proof of concept, it requires some fixes like:

• make sure all elements of Array are of the same class (to avoid mixing pears and apples);
• make sure the above class extends ActiveRecord::Base;
• [].reactiverecordize should return an instance of ActiveRecord::NullRelation.