How to check if that data already exist in the database during update Mongoose And Express

Question

How to do validations before saving the edited data in mongoose   For example  if sample name already exists in the database  the user will receive a some sort of error  something like that  here s my code below    Post   sample edit app post uri     edit   function  req  res  next      Sample findById req param  sid    function  err  sample         if  err          return next new Error err               if   sample          return next new Error  Invalid reference to sample information                   basic info     sample name   req body supplier name      sample tin   req body supplier tin          contact info     sample contact email   req body supplier contact email      sample contact mobile   req body supplier contact mobile      sample contact landline   req body supplier contact landline      sample contact fax   req body supplier contact fax          address info     sample address street   req body supplier address street      sample address city   req body supplier address city      sample address state   req body supplier address state      sample address country   req body supplier address country      sample address zip   req body supplier address zip       sample save function  err          if  err            return next new Error err                   res redirect uri     view     sample  id

User · Answer

For anybody falling on this old solution  There is a better way from the mongoose docs   var s   new Schema   name    type  String  unique  true      s path  name   index   unique  true

User · Answer

If you re searching by an unique index  then using UserModel count may actually be better for you than UserModel findOne due to it returning the whole document  ie doing a read  instead of returning just an int

User · Answer

Another way to continue with the example  nfreeze used is this validation method   UserModel schema path  name   validate function  value  res        UserModel findOne  name  value    id   function err  user            if  err  return res err           if  user  return res false           res true               already exists

User · Answer

Here is another way to accomplish this in less code   UPDATE 3  Asynchronous model class statics  Similar to option 2  this allows you to create a function directly linked to the schema  but called from the same file using the model   model js   userSchema statics updateUser   function user  cb      UserModel find  name   user name   exec function err  docs        if  docs length         cb  Name exists already   null         else         user save function err            cb err user                           Call from file  var User   require    path to model     User updateUser user name  function err  user      if err        var error   new Error  Already exists         error status   401      return next error

User · Answer

check with one query if email or phoneNumber already exists in DB  let userDB   await UserS findOne    or        email  payload email        phoneNumber  payload phoneNumber         if  userDB      if  payload email    userDB email        throw new BadRequest   message   E-mail already exists         else if  payload phoneNumber    userDB phoneNumber        throw new BadRequest   message   phoneNumber already exists

User · Answer

Typically you could use mongoose validation but since you need an async result  db query for existing names  and validators don t support promises  from what I can tell   you will need to create your own function and pass a callback  Here is an example   var mongoose   require  mongoose        Schema   mongoose Schema      ObjectId   Schema ObjectId   mongoose connect  mongodb   localhost testDB     var UserSchema   new Schema       name   type String       var UserModel   mongoose model  UserModel  UserSchema    function updateUser user cb       UserModel find  name   user name   function  err  docs            if  docs length               cb  Name exists already  null            else              user save function err                   cb err user                                        UserModel findById req param  sid   function err existingUser      if   err  amp  amp  existingUser          existingUser name    Kevin          updateUser existingUser function err2 user              if  err2     user                  console log  error updated user    err2               else                 console log  user updated    user                                        UPDATE  A better way  The pre hook seems to be a more natural place to stop the save   UserSchema pre  save   function  next        var self   this      UserModel find  name   self name   function  err  docs            if   docs length               next             else                              console log  user exists    self name               next new Error  User exists                               UPDATE 2  Async custom validators  It looks like mongoose supports async custom validators now so that would probably be the natural solution       var userSchema   new Schema         name            type  String          validate              validator  function v  cb                User find  name  v   function err docs                  cb docs length    0                                          message   User already exists

User · Answer

There is a more simpler way using the mongoose exists function router post  quot  groups members quot   async  ctx    gt        const group name   ctx request body group membership group name      const member name   ctx request body group membership group members      const GroupMembership   GroupModels GroupsMembers      console log  quot group name    quot   group name   quot member    quot   member name       try           if                await GroupMembership exists                    quot group membership group name quot   group name                      false                         console log  quot new function quot                const newGroupMembership   await GroupMembership insertMany                   group membership                          group name  group name  group members   member name                                                    await newGroupMembership save              else               const UpdateGroupMembership   await GroupMembership updateOne                     quot group membership group name quot   group name                       push     quot group membership   group members quot   member name                                 console log  quot update function quot                await UpdateGroupMembership save                      ctx response status   201          ctx response message    quot A member added to group successfully quot         catch  error            ctx body                 message   quot Some validations failed for Group Member Creation quot               error  error message                     console log error           ctx throw 400  error

User · Answer

In addition to already posted examples  here is another approach using express-async-wrap and asynchronous functions  ES2017    Router  router put    id settings profile   wrap async function  request  response  next        const username   request body username     const email   request body email     const userWithEmail   await userService findUserByEmail email      if  userWithEmail            return response status 409  send  message   Email is already taken               const userWithUsername   await userService findUserByUsername username      if  userWithUsername            return response status 409  send  message   Username is already taken               const user   await userService updateProfileSettings userId  username  email      return response status 200  json  user  user         UserService  async function updateProfileSettings  userId  username  email        try           return User findOneAndUpdate    id   userId                  set                     username   username                   auth email   email                           new  true         catch  error            throw new Error  Unable to update user with id    userId               async function findUserByEmail  email        try           return User findOne   auth email   email toLowerCase           catch  error            throw new Error  Unable to connect to the database             async function findUserByUsername  username        try           return User findOne   username   username         catch  error            throw new Error  Unable to connect to the database                other methods  export default       updateProfileSettings      findUserByEmail      findUserByUsername      Resources  async function  await  express-async-wrap

[node.js] How to check if that data already exist in the database during update (Mongoose And Express)

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