mongodb count embeded objects by an atrribute

countembeded.js

var map = function() { emit(this.e, { notifications : this.notifications});};

var reduce = function(key, values) { 
	var count = 0;
  values.forEach(function(docs) { 
	for(var doc in docs.notifications){
		if(docs.notifications[doc].date>1332836355){
			count+=1;
		}
	}
  });
  return { c : count};
};

db.collection1.mapReduce(map, reduce, {out: collection2});