to_json

railsの配列を簡単にjsonにしてくれる便利メソッド

{"word":<%= @word.to_json(:only => [:id, :title]) %>
  "parents":<%= @word.parents.map{|w|w.from}.to_json(:only => [:id, :title]) %>
  "children":<%= @word.children.map{|w|w.to}.to_json(:only => [:id, :title]) %>
}

http://apidock.com/rails/ActiveRecord/Serialization/to_json