Map reduce problem

map reduce

map function:

function(doc) {
    if(doc.symbol.lastIndexOf("HFF") == 0){    
    emit(doc.symbol,{last_update:doc.last_updatedutc,symbol:doc.symbol,last_yield:doc.last_yield});
    }
}

View output:

{"total_rows":19,"offset":0,"rows":[
{"id":"HFF1502242012-02-22 15:59:59","key":"HFF150224","value":{"last_update":"2012-02-22 15:59:59.00","symbol":"HFF150224","last_yield":0.01094398}},
{"id":"HFF1502242012-02-22 18:04:10.4398","key":"HFF150224","value":{"last_update":"2012-02-22 18:04:10.43","symbol":"HFF150224","last_yield":0.01094398}},
{"id":"HFF1502242012-02-23 09:21:04.5628","key":"HFF150224","value":{"last_update":"2012-02-23 09:21:04.56","symbol":"HFF150224","last_yield":0.01093423}}
]}

Reduce function:

function(keys, values, rereduce) {
    var max_ts = "";
    var max_id = null;
        
    for (var idx=0; idx<values.length; idx++){
        if (values[idx].last_update > max_ts) {
            max_ts = values[idx].last_update;
            max_id = values[idx].symbol;
        }
    }
    return { "symbol": max_id, "last_update": max_ts};

}

result (reduce=true&group=true):

{"rows":[
{"key":"HFF150224","value":null}]}