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);
  }
});