Lazily convert an Enumerator or Enumerator::Lazy to a JSON array. Save as config/initializers/enumerator_to_json.rb

enumerator_to_json.rb

# Natively, Enumerators get JSONized like "#<Enumerator::Lazy:0x007f8714807080>", or they explode, either of which is a problem.
# We want them to make an array, and do it lazily so we don't have to keep the items in memory!
class Enumerator
  def to_json(state)
    state.depth += 1

    string = "[\n"
    first_item = true

    self.each do |item|
      separator = ",\n" unless first_item

      as_json = item.as_json

      indentation = state.indent * state.depth
      string << "#{separator}#{indentation}#{as_json.to_json(state)}"

      first_item = false
    end

    state.depth -= 1

    indentation = state.indent * state.depth
    string << "\n#{indentation}]"
  end
end