Mongoose mapReduce Error: OUT parameter must be defined - node.js

Question

I am using mongoose framework to communicate with the mongodb. Now i am in the situation to join the two collections using mapReduce. I have followed this tutoria "http://blog.knoldus.com/2014/03/12/easiest-way-to-implement-joins-in-mongodb-2-4/" to get it done.
I have successfully done with join using mapReduce in mongoDB Shell using robomongo.
Same i am trying with mongoose frame work but its giving me error that Out parameter must be defied.
The code sample what i have done.
This is the collection schema for User profile:
var User = new mongoose.Schema({
name : {
first : {type : String},
last : {type : String}
},
title : {type : String},
userName : {type : String, unique : true},
profileImgUrl : {type : String},
mojo : Number
});
this is the collection schema for the testimonials:
var Testimonials = new mongoose.Schema({
from : String,
to : String,
text : String
});
This is the code using mongoose, nodejs:-
var mapTalent = function () {
var output= {userName : this.userName,firstname:this.name.first, lastname:this.name.last , profileImgUrl : this.profileImgUrl, mojo : this.mojo, text : null}
emit(this.userName, output);
};
var mapTestimonial = function () {
var output = {fromTalentName : this.fromTalentName, firstname:null, lastname:null, profileImgUrl : null, mojo : null, text : this.text}
emit(this.text, output);
};
var reduceF = function(key, values) {
var outs = {firstname:null, lastname:null , profileImgUrl:null, text : null, mojo:null};
values.forEach(function(v){
if(outs.firstname ==null){
outs.firstname = v.firstname
}
if(outs.lastname ==null){
outs.lastname = v.lastname
}
if(outs.profileImgUrl ==null){
outs.profileImgUrl = v.profileImgUrl
}
if(outs.mojo ==null){
outs.mojo = v.mojo
}
if(outs.text == null){
outs.text = v.text
}
});
return outs;
};
result = Testimonials.mapReduce(mapTestimonial, reduceF, {out : {reduce : "Talent_Testimonials"}});
result = Talent.mapReduce(mapTalent, reduceF, {out : {reduce : "Talent_Testimonials"}});
Here the error is thrown as " the out option parameter must be defined".
What i am doing wrong here i am not getting. This same works in mongoDB shell.

Answer 1

mapReduce can't be called the same way in Mongoose as it is in the shell.
For Mongoose, the call would need to look like:
Testimonials.mapReduce({
map: mapTestimonial,
reduce: reduceF,
out : {reduce : "Talent_Testimonials"}
}, function (err, results) { ... });
See the docs here.