document must have an _id before saving mongoose error

Question

I am trying to create a schema.

I keep getting the document does not have an _id error, besides the code below I did try to initialize it explicitly, but nothing works.

var UserSchema = new mongoose.Schema({
     _id: mongoose.Schema.ObjectId,
     username: String,
     password: String
 });

var User = mongoose.model('user', UserSchema);

Answer 1

http://mongoosejs.com/docs/guide.html#_id reads:

Mongoose assigns each of your schemas an _id field by default if one is not passed into the Schema constructor.

If you explicitly define _id type in the schema, it's your responsibility to set it:

User._id = mongoose.Types.ObjectId('000000000000000000000001');