How To Create Mongoose Schema with Array of Object IDs?

Question

I have defined a mongoose user schema:

var userSchema = mongoose.Schema({   email: { type: String, required: true, unique: true},   password: { type: String, required: true},   name: {       first: { type: String, required: true, trim: true},       last: { type: String, required: true, trim: true}   },   phone: Number,   lists: [listSchema],   friends: [mongoose.Types.ObjectId],   accessToken: { type: String } // Used for Remember Me });  var listSchema = new mongoose.Schema({     name: String,     description: String,     contents: [contentSchema],     created: {type: Date, default:Date.now} }); var contentSchema = new mongoose.Schema({     name: String,     quantity: String,     complete: Boolean });  exports.User = mongoose.model('User', userSchema); 

the friends parameter is defined as an array of Object IDs. So in other words, a user will have an array containing the IDs of other users. I am not sure if this is the proper notation for doing this.

I am trying to push a new Friend to the friend array of the current user:

user = req.user;   console.log("adding friend to db");   models.User.findOne({'email': req.params.email}, '_id', function(err, newFriend){     models.User.findOne({'_id': user._id}, function(err, user){       if (err) { return next(err); }       user.friends.push(newFriend);     });   }); 

however this gives me the following error:

TypeError: Object 531975a04179b4200064daf0 has no method 'cast'

Answer 1

If you want to use Mongoose populate feature, you should do:

var userSchema = mongoose.Schema({   email: { type: String, required: true, unique: true},   password: { type: String, required: true},   name: {       first: { type: String, required: true, trim: true},       last: { type: String, required: true, trim: true}   },   phone: Number,   lists: [listSchema],   friends: [{ type : ObjectId, ref: 'User' }],   accessToken: { type: String } // Used for Remember Me }); exports.User = mongoose.model('User', userSchema); 

This way you can do this query:

var User = schemas.User; User  .find()  .populate('friends')  .exec(...) 

You'll see that each User will have an array of Users (this user's friends).

And the correct way to insert is like Gabor said:

user.friends.push(newFriend._id);