quickly convert json (array of equally structured objects) into csv

json2csv.rb

#!/usr/bin/env ruby                                                                       

require 'json'
require 'csv'

CSV do |csv|
  data = JSON.parse(ARGF.read)
  csv << data.first.keys.sort
  data.each do |line|
    csv << line.to_a.sort_by { |a| a.first }.map { |a| a.last }
  end
end