MongoDB Product MapReduce 2

gistfile1.js

map = function map(){
      var size;
      for (size in this.sizes) {
	  emit(size, this.sizes[size]);
      }
};

reduce = function reduce(key,values){
         var result = { count: 0 };

  	 values.forEach(function(value){
  		result.count += value;
  	 });
  	
    return result;
}
> db.product.mapReduce(map,reduce,{out:"productMapReduce2"})
{
	"result" : "productMapReduce2",
	"timeMillis" : 2,
	"counts" : {
		"input" : 6,
		"emit" : 18,
		"reduce" : 3,
		"output" : 3
	},
	"ok" : 1,
}
> db.productMapReduce2.find()
{ "_id" : "L", "value" : { "count" : 11 } }
{ "_id" : "XL", "value" : { "count" : 19 } }
{ "_id" : "XXL", "value" : { "count" : 24 } }