Use find on a model inside a model

Question

Use find on a model inside a model

I'm trying to use the mongoose find method to find an object on an unknown object. Here is the code to explain better.

Here are my models :

var Screen = new mongoose.Schema({
    id : Number,
    pid : Number,
    uploaded : {type: Date, default: Date.now },
    name : String,
    url : String,
    shorty : String
});

var User = new mongoose.Schema({
  id : Number,
  mail:    { type : String, match : /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/ },
  pass:  String,
  token:  String,
  inscDate: { type: Date, default: Date.now },
  lastConnec:     { type: Date, default: Date.now },
  screens:   [Screen],
  lastIp : String,
  valid : { type: Boolean, default : 0}
});

var UserModel = mongoose.model('users', User);
var ScreenModel = mongoose.model('screens', Screen);

So the thing is that my user model contains an array of screens. Basically I want to search a precise screen for an unknown user. Doing something like this :

var query = UserModel.find({'screens.shorty' : shorty});
query.exec(function(err, screenR) {

    });

But this code crashes, and the other similar codes I tried never returns anything else than an empty array. And my search isn't wrong (I tried to copypasta an exact string).

Is there any working way to do that ?

javascript
node.js
mongodb
mongoose

Answer 1

If you're using MongoDB 2.2+ you can use the $ projection operator to have screens filtered to the first element that matches your query selector.

Like this:

var query = UserModel.findOne({'screens.shorty': shorty}, {'screens.$': 1});
query.exec(function(err, user) {
    if (user) {
        // user.screens[0] contains the first element with the matching shorty field
    }
});

Answer 2

Okay, I managed to make this work. Not sure this is the most elegant way, but at least it is a way :

var query = UserModel.find({'screens.shorty' : shorty}); // That query will get me the correct user, but not the screen
query.exec(function(err, screenR) {
    if (err) throw err;
    if (screenR[0]){ 
        for (var i in screenR[0].screens){ // I loop through all the screens
            if (screenR[0].screens[i].shorty == shorty) {
                // Here I have the correct screen and can do whatever with it.
            }

        }

    } else {
        // If no result
    }
});