Avoid duplicate entries on Mongoose array

Question

I have a many to many relation using mongoose, that looks like this.

TeamSchema = new Schema 
    name : String
    players: [{ type: ObjectId, ref: \'Player         


        

Answer 1

Use the $addToSet update operator like so:

Team.update({_id: team._id}, {$addToSet: {players: player}})

Assuming player is the ObjectId of a player, it will only be added to the team's players array if it's not already present.