node.js - Mongoose - FindOneAndUpdate - Type Error -

i having troubles implementing findoneandupdate query.

//usercontroller  userdao                                                                                                          ['findoneandupdate'](userid, {'passwordtoken': passwordtoken, 'resetpasswordexpires': resetpasswordexpires})   .then( (user) => {                                                                                               return mailcontroller.forgotpasswordmail(user, hosturl);                                                     })                                                                                                             .then( (updated) => {                                                                                            return res.status(200).json(updated);                                                                        })                                                                                                             .catch(error => {                                                                                                return res.status(400).json(error);                                                                          });                                                                                                           //userdao  userschema.static('findoneandupdate', (userid, query) => {   return new promise((resolve, reject) => {     if (!_.isobject(query)) {       return reject(new typeerror('query not valid object.'));     }      user       .findoneandupdate(         {_id: userid},         query,         {upsert: true}       )       .exec((err, updated) => {       err ? reject(err) : resolve(updated);     });   }); }); 

these 2 methods on usercontroller , on userdao. once execute them, logs out "findoneandupdate.exec not method". weird things returning moongose methods way.

what doing wrong?

once finished writing question figured out whats problem. function name "findoneandupdate" crashing findoneandupdate original mongoose function. change function name , solved problem!