Mongoose model with array logic - arrays

Question

I'm currently training with Mongoose and to do so I'm building a little messaging app.
I have a collection of user, here is the User.js :
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var UserSchema = new Schema({
username: String,
password: String
});
module.exports = mongoose.model('User', UserSchema);
now I want to write a chatroom model that should contain a list of users, how should I proceed ? Here is my current Chatroom.js :
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var ChatroomSchema = new Schema({
name: String,
password: String,
members: ???
});
module.exports = mongoose.model('Chatroom', ChatroomSchema);
Finally I would like to know how to post a user in that members array when creating a chatroom, here is my route code for /chatroom :
router.route('/chatroom')
.post(function(req, res) {
var chatroom = new Chatroom();
chatroom.name = req.body.name;
chatroom.password = encrypt(req.body.password,chatroom.name);
chatroom.members = ???;
chatroom.save(function(err) {
if (err)
res.send(err);
res.json({ message: 'Chatroom created!' });
});
});
Is there a specific way to bind a user to the members array or should I just define members as an array of string :
members : {username:String}

Answer 1

Population would be ideal in your case. From the docs:
Population is the process of automatically replacing the specified
paths in the document with document(s) from other collection(s).
Population will seamlessly help you bring data from the Users collection into your Chatroom model. Consider the following example to illustrate this approach:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var ChatroomSchema = new Schema({
name: String,
password: String,
members: [{ type: Schema.Types.ObjectId, ref: 'User' }]
});
module.exports = mongoose.model('Chatroom', ChatroomSchema);
In your chatroom schema definition, you add a list of primary surrogate keys to each object, called ObjectId, referenced as _id in the data by surrounding the field definition members in square brackets to get this functionality. These will be the keys used to refer to documents in the User collections.
Note:- When you define the references, the ref attribute must match exactly the model name in your model definition else you will get an error (suppose you refer to a non-existing Member model or Users)
MissingSchemaError: Schema hasn't been registered for model "Member"..
Reading the data
This is where Mongoose population shows how easy and fast it is to makes reads of documents very straightforward through its populate() function. So for instance, to show the referenced users in a chatroom, call the populate() method with the name of that field in a string as a parameter e.g.
Chatroom.findOne({"_id": chatId})
.populate("members")
.exec(err, chats) { ... }
Writing data
When you save data for the Chatroom model, you will also need to save the references to the users. For instance, when a new Chatroom is created, you'll need an array of User references saved as the members field:
router.route('/chatroom')
.post(function(req, res) {
var chatroom = new Chatroom();
var usersIds = ["54b5659536cd5250a3a93bd3", "54b5659836cd5250a3a93bd4"]; // <-- an array with members ids, for example.
chatroom.name = req.body.name;
chatroom.password = encrypt(req.body.password,chatroom.name);
chatroom.members = usersIds;
chatroom.save(function(err) {
if (err)
res.send(err);
res.json({ message: 'Chatroom created!' });
});
});

Answer 2

Try with referenced documents
Chatroom.js
var ChatroomSchema = new Schema({
name: String,
password: String,
members: [Schema.Types.ObjectID, ref = 'user']
});
Controller
router.route('/chatroom')
.post(function(req, res) {
var chatroom = new Chatroom();
chatroom.name = req.body.name;
chatroom.password = encrypt(req.body.password,chatroom.name);
chatroom.members = req.user; // if the user is authenticated
chatroom.save(function(err) {
if (err)
res.send(err);
res.json({ message: 'Chatroom created!' });
});
});