Mongoose Obtener ID después de salvar
n.save(function(err,room){
var newRoomId = room._id;
});
florinrelea
n.save(function(err,room){
var newRoomId = room._id;
});//if you are sending an id field in req.body then mongoose will return e null _id
//to solve this just delete the _id field before running the save method
if(req.body._id === null) {
delete req.body._id;
}