gistfile1.as

require 'json'

first = JSON.parse File.read 'first.json'
second = JSON.parse File.read 'second.json'
third = JSON.parse File.read 'third.json'

categories = []

first['filterElementCommands'].each_with_index do |top_level_category_info, index|
	top_category = { info: top_level_category_info }
	top_category[:parents] = []
	second[index]['filterElementCommands'].each_with_index do |second_level_category_info, index|
		second_category = { info: second_level_category_info }
		second_category[:parents] = [top_category]
		second_category_children = third[index]['filterElementCommands']
		if second_category_children.any?
			second_category_children.each_with_index do |third_level_category_info, index|
				third_category = { info: third_level_category_info }
				third_category[:parents] = [top_category, second_category]
				categories << third_category
			end
		else
			categories << second_category
		end
	end
end

File.open('output.json', 'w') { |f| f << JSON.dump(categories) }