TagCloud map/reduce Mongo Mapper

gistfile1.rb

class TagCloud
  MAP = <<-JS
          function () {
            this.tags.forEach(function (tag) {
              emit(tag, 1);
            });
          }
        JS

  REDUCE = <<-JS
             function (prev, current) {
               var count = 0;
               for (index in current) {
                 count += current[index];
               }
               return count;
             }
           JS
           
  def self.build
    Post.collection.map_reduce(MAP, REDUCE).find.to_a
  end
end