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JavaScript

Jonathan Haro
Jonathan Haro
18,101 Points
Posted by Jonathan Haro
Jonathan Haro
18,101 Points

How would I check to see if an email entered in a registration form was already in the a mongo database?

Would I add an 'else if' block after the 'if' block which confirms that the passwords entered at the form match?

else if (User.findOne({req.body.email}) == true ) {
        var err = new Error('A user with that email has already registered. Please use a different email..')
        err.status = 400;
        return next(err);
}

pretty sure you can't use methods like 

User.findOne({req.body.email})

within a route.

If that's the case then does this check happen in the user.js? Would I create another method off the UserSchema.statics like:

UserSchema.statics.emailCheck = function(email, callback) {

}

3 Answers

Aemiro Allison
Aemiro Allison
480 Points
Aemiro Allison
Aemiro Allison
480 Points

If your User Schema has an email field then you can check the email field on the User model with the email entered from the form in req.body.email

//a simple if/else to check if email already exists in db
User.findOne({ email: req.body.email }, function(err, user) {
   if(err) {
      //handle error here
   }

   //if a user was found, that means the user's email matches the entered email
   if (user) {
         var err = new Error('A user with that email has already registered. Please use a different email..')
        err.status = 400;
        return next(err);
   } else {
       //code if no user with entered email was found
   }
});
Jonathan Haro
Jonathan Haro
18,101 Points
Jonathan Haro
Jonathan Haro
18,101 Points

Ok so this is what I have in my User model:

UserSchema.statics.emailCheck = function(email, callback) {
  User.findOne({ email: req.body.email })
    .exec(function (error, user) {
      if (error) {
        return callback(error);
      } else if ( user ) {
        var err = new Error('A user with that email has already registered. Please use a different email.');
        err.status = 401;
        return next(err);
      }
    });
};

Would I then add code in my index.js to run the above function?

      User.emailCheck(req.body.email, function (error, user) {
        if (error) {
          return next(err);
        }
      });
Seth Kroger
Seth Kroger
56,415 Points
Seth Kroger
Seth Kroger
56,415 Points

Are you using Mongoose? Model.findOne() never returns the actual document, which would be a synchronous action. It either takes a callback that runs when the query is finished or returns a query if you didn't specify a callback which needs to be exec()ed with a callback or promise.

Aemiro Allison
Aemiro Allison
480 Points
Aemiro Allison
Aemiro Allison
480 Points

You do not have access to the next() function when creating your User model, so you must return the error or user (either will work fine) to the callback. You also don't have access to the request object in your User model definition, so you need to replace 'req.body.email' with entered argument 'email'.

Also in your User model, if the email does not exist, all the code within the exec function's callback will be ignored and can lead to hidden errors. You should call the callback with the user to keep code exceution predictable if an email is found or not.

Lastly, if your going to use 'next(err)' to throw your errors then you should have an error handling express middleware to catch all your errors. (https://expressjs.com/en/guide/error-handling.html)

UserSchema.statics.emailCheck = function(email, callback) {
  // replaced req.body.email with email
  User.findOne({ email: email })
    .exec(function (error, user) {
      if (error) {
        return callback(error);
      }

      // Pass user to callback and handle whether email exist in the callback.
      callback(null, user);
    });
};

  User.emailCheck(req.body.email, function (error, user) {
        if (error) {
          return next(error);
        }

        if( user ) {
             // Tell client that the email already exist.
             res.status(401).json({error: 'User with email already found'});
        } else {
            // Code if no user with entered email was found. 
            res.json({ message: 'Successfully created account.'});
        }
    });