Map reduce with mongoosejs - node.js

Question

I'm trying to get a map reduce operation to work using Nodejs, mongoose and MongoDB.
I've got a fairly flat schema structure and I want to get a list of value/date pairs per 'named' object. There is clearly something wrong with the map reduce function but I can't see how to fix it to get the format I'm after.
The MongoDB document schema is as follows:
{ "name" : "object1", "value" : "123", "date" : "2013-01-02 01:00:00" }
{ "name" : "object1", "value" : "456", "date" : "2013-01-02 02:00:00" }
{ "name" : "object2", "value" : "123", "date" : "2013-01-02 02:00:00" }
The map reduce functions I'm using in my Mongoose Schema are as follows:
var o = {};
o.map = function () {
emit(
{ 'name': this.name },
{'data': [ { 'value': this.value, 'date': this.date} ] }
)
}
o.reduce = function (k, vals) {
var reduced = {'data': []};
for (var i in vals) {
reduced.data.push(vals[i]);
}
return reduced;
}
this.mapReduce(o, function(err, model) {
if(err) console.log(err);
model.find().exec(cb);
});
What I'd like to see is some JSON along the lines of
[
{
"name": "object1",
"data": [
{
"value": "123",
"date": "2013-01-02T01:00:00.123456"
},
{
"value": "456",
"date": "2013-01-02T02:00:00.123456"
},
]
},
{
"name": "object2",
"data": [
{
"value": "123",
"date": "2013-04-22T13:10:03.893018"
},
...
]
},
...
But I end up getting this nested mess! Can someone give me a pointer on what I've missed!!
[
{
"_id": {
"name": "object1"
},
"value": {
"data": [
{
"data": [
{
"data": [
{
"data": [
{
"value": "123",
"date": "2013-01-02T02:00:00.123456"
}
]
},
{
"data": [
{
"value": "465",
"date": "2013-01-02T01:00:00.123456"
}
]
},
... etc

Answer 1

try something like that: (not tested but the idea is here I think :))
var o = {};
o.map = function () {
emit(this.name, { 'value': this.value, 'date': this.date} )
}
o.reduce = function (k, vals) {
var reduced = {name: k, data : []};
for (var i in vals) {
reduced.data.push(vals[i]);
}
return reduced;
// or just return vals? it's already the array you want.
}