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 som

Answer 1

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);
  }
});

Answer 2

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