mongodb group by day

mongodb-group-by-day.js

/**
 * group by day
 * @link https://gist.github.com/phnessu4/5636642
 * @param query document {key1:123,key2:456}
 */
var count_by_day = function(query){
    return db.action.group(
    {
        keyf: function(doc) {
            var date = new Date(doc.time);
            var dateKey = (date.getMonth()+1)+"/"+date.getDate()+"/"+date.getFullYear();
            return {'date': dateKey};
        },
        cond:query,
        initial: {count:0},
        reduce: function(obj, prev) {
          prev.count++;
        }
    });
}

count_by_day({this:'is',the:'query'})