If you explicitly declare _id: Schema.ObjectId for your model, then the ObjectId will not be available after new or save.

If you explicitly declare

_id: Schema.ObjectId

for your model, then the ObjectId will not be available after new or save.

[aheckmann]

ah, the docs were incorrectly hiding the option you need (will be fixed next time they’re published).

you must pass the auto option like so:

new Schema({ _id: { type: Schema.ObjectId, auto: true }})

[jeshuneo]

new Schema({ _id: { type: Schema.ObjectId, auto: true }}) “CHANGE (_id) to (id)”