node.js mongodb one-to-many association error - node.js

Question

I got a One-to-Many association error between(user 1<--->1..*robot) , I want to add a new document when a new user subscribe he should add a new robot with (reference and nom), so the user information should be add on the user collection as new document and the robot information should be add as a new collection on the robot collection in my mongodb database.
/routes/users.js :
router.post('/register', function(req, res, next) {
//tester si username exist
var user = new models.user({
nom_prenom: req.body.nom_prenom,
username: req.body.username,
password: req.body.password,
email: req.body.email,
sexe: req.body.sexe,
adresse: req.body.adresse,
admin: false
});
var robot = new models.robot({
reference: req.body.reference,
nom: req.body.nom,
flag: req.body.flag
});
user.save(function(err, u){
if(err) res.json(err);
res.json(u);
})
robot.save(function(err, u){
if(err) res.json(err);
res.json(u);
})
});
/models/users.js :
var mongoose = require('../config/db');
var UserSchema = mongoose.Schema({
nom_prenom: String,
password: String,
username: String,
email: String,
//username: { String, unique:true, required:true },
//email: { String, unique:true, required:true },
date_naissance: Date,
adresse: String,
sexe: String,
equipements:[{type: mongoose.Schema.Types.ObjectId, ref: 'Equipement'}],
robots:[{type: mongoose.Schema.Types.ObjectId, ref: 'Robot'}],
admin: Boolean
});
module.exports = mongoose.model('User', UserSchema);
/models/robot :
var mongoose = require('../config/db');
var RobotSchema = mongoose.Schema({
reference: String,
nom: String,
flag: Boolean,
user: { type: mongoose.Schema.Types.ObjectId, ref: 'User' }
});
module.exports = mongoose.model('Robot', RobotSchema);
/routes/robots.js:
router.get('/', function(req, res, next){
models.robot.aggregate([
{
"$group": {
"_id": "$user_id",
"robots": { "$push": "$$ROOT" }
}
}
]).exec(function(err, results){
if (err) res.json({error: err});
models.user.populate(results, { "path": "_id" }, function(err, result) {
if(err) res.json({error: err});
console.log(result);
res.json(result);
});
});
});
the result Postman:
The Result on CMD after i execute :db.robots.find().pretty();
{
"_id" : ObjectId("57b5862673c11c840b31cc55"),
"reference" : "Rob9999",
"nom" : "Robot 9999",
"flag" : false,
"__v" : 0
}
and the result on CMD after I execute db.users.find().pretty();
{
"_id" : ObjectId("57b5862673c11c840b31cc54"),
"nom_prenom" : "test",
"username" : "test",
"password" : "test",
"email" : "test#orange.tn",
"sexe" : "femme",
"adresse" : "tunis",
"admin" : false,
"robots" : [ ],
"equipements" : [ ],
"__v" : 0
}
I don't find why the array robots in user is empty??
Can I do that insert a user and a robot that should appear in the list of robots of that user?

Answer 1

I think you didn't push newly created robot's _id to the robots array in user document while saving it.
Try This:
router.post('/register', function(req, res, next) {
//tester si username exist
var user = new models.user({
nom_prenom: req.body.nom_prenom,
username: req.body.username,
password: req.body.password,
email: req.body.email,
sexe: req.body.sexe,
adresse: req.body.adresse,
admin: false
});
var robot = new models.robot({
reference: req.body.reference,
nom: req.body.nom,
flag: req.body.flag
});
// dont change the header(res.json(u)) multiple times, make sure you set the header
// single time only. otherwise you may get unnecessary errors.
robot.save(function(err, u){
if(err) res.json(err);
//save user only after robot is successfully saved and push its id into robots array.
user.robots.push(u._id);
user.save(function(err, user){
if(err) res.json(err);
res.json(user);
return;
});
});
});