boolean_value.rb

class BooleanValue
  # https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/column.rb#L8
  FALSE_VALUES = [false, 0, "0", "f", "F", "false", "FALSE", "off", "OFF"]

  def self.convert(value)
    Rails.present? ? with_rails(value) : without_rails(value)
  end

  private

  def self.with_rails(value)
    major, minor, patch = Rails.version.split(".").map(&:to_i)
    case major
    # Rails 5
    when 5
      ActiveRecord::Type::Boolean.new.cast(value)
    # Rails 4
    when 4
      # Rails < 4.2
      if minor < 2
        ActiveRecord::ConnectionAdapters::Column.value_to_boolean(value)
      # Rails >= 4.2
      else
        ActiveRecord::Type::Boolean.new.type_cast_from_user(value)
      end
    # Other
    else
      without_rails value
    end
  end

  # as defined in Rails 5:
  # everything, except empty string and FALSE_VALUES considered as TRUE
  def self.without_rails(value)
    value == "" ? nil : !FALSE_VALUES.include?(value)
  end
end