db.pmusers.aggregate([
	{
	    $addFields : {
		    "todayDayOfYear" : {
		        "$dayOfYear" : new Date()
		    },
		    "birthDayOfYear" : {
		        "$dayOfYear" : new Date(Date.UTC('$dateOfBirth.year', '$dateOfBirth.month', '$dateOfBirth.day'))				
		    },
			'year' : '$dateOfBirth.year',
			'month' : '$dateOfBirth.month',
			'day' : '$dateOfBirth.day',
			'date' : Date.UTC('$dateOfBirth.year', '$dateOfBirth.month', '$dateOfBirth.day')
	    }		
	}
]).pretty()

{
        "todayDayOfYear" : 215,
        "birthDayOfYear" : 1,
        "year" : 2010,
        "month" : 4,
        "day" : 7,
        "date" : NaN
}