MongoDB Mongoose save object with nested objects - mongodb

Question

I'm new to MongoDB and I'm creating a simple db with Mongoose with the following models: User, Game and Players.
So, one user contains none or many games. Every game has to players, and each player refers to a user. Like this (I simplified the schemas for clarity):
const UserSchema = new Schema({
name: String,
games: [{
type: Schema.Types.ObjectId,
ref: 'game'
}]
});
const GameSchema = new Schema({
mode: Number,
players: {
type: [{
type: Schema.Types.ObjectId,
ref: 'player'
}],
required: true
}
});
const PlayerSchema = new Schema({
order: Number,
isWinner: Boolean,
user: {
type: Schema.Types.ObjectId,
ref: 'user',
required: true
}
});
So, now in the frontend I want to send a petition to the backend to create a new game for users Joe (_id:11111) and Bob (_id:22222) and so I send a POST to /api/games with the body { users: [ 11111, 22222 ] }
Now my question is, for the backend to create a new game, it also has to create 2 players. What's the best way to achieve this?
In the Game.create() method, shall I retrieve the data, create and save the players, create the game, assign the players, save the game, and also update the users and add the game ids?
I also read about Mongoose middleware, where you can set certain functions to be executed before or after some operations. So maybe it's better:
pre function before Game.create, to create the players
post function before Game.create, to update the users
This last one seems cleaner.
What's the best way? Maybe another one I have not considered?
Thanks

Answer 1

I would suggest you using the post and pre functions defined in the mongoose middleware. They're pretty straightforward and neat to use. It will probably solve your problem.
Here is a personal example of a problem we had; In our case, we had to assign a userId from a sequence in the database. We used the following code:
var UserSchema = new Schema({
username: { type: String, required: true, unique: true },
id: { type: String },
...
});
UserSchema.pre('save', function(next) {
let doc = this;
let id = 'userSeq'
Sequence.findByIdAndUpdate(id, { $inc : {nextSId : 1} }, function(error,data) {
if(error)
next(error)
doc.id = data.nextSId-1;
next();
})
});
My suggestion is that before you create the game, you can search for the users and add a reference to the game. If I were you, I would use the findAndModify query of mongodb to find the users or create if they do not exist yet.