If you're building a web application that requires user authentication, you'll
need to validate user input, including email addresses. In this article, we'll
explore how to validate email addresses using Mongoose, a popular Node.js ORM
for MongoDB.

What is email validation?

Email validation is the process of verifying whether an email address is valid
and exists. There are several ways to validate email addresses, including
checking the syntax of the email address, checking the domain name, and
checking if the email address exists on the mail server. Validating email
addresses is important because it helps prevent fraudulent activities such as
spamming and phishing.

Why use Mongoose for email validation?

Mongoose is a popular ORM for MongoDB that provides schema validation out of
the box. Schema validation enables you to define rules for your data, ensuring
that it conforms to a specific structure. This makes it easy to validate email
addresses, as you can define a schema for your user model that includes an
email field with validation rules.

How to validate email addresses using Mongoose?

To validate email addresses using Mongoose, you'll need to define a schema for
your user model that includes an email field with validation rules. Here's an
example:

const mongoose = require('mongoose');const userSchema = new mongoose.Schema({email: {type: String,required: true,unique: true,validate: {validator: function(v) {return /[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}/i.test(v);},message: props => `${props.value} is not a valid email address!`}}});const User = mongoose.model('User', userSchema);

In this example, we define a user schema with an email field that is required,
unique, and has a custom validation function that checks if the email address
is valid. The custom validation function uses a regular expression to check
the syntax of the email address. If the email address is invalid, Mongoose
will throw a validation error with the specified message.

Common errors when validating email addresses with Mongoose

When validating email addresses with Mongoose, you may encounter some common
errors. One of the most common errors is the "email is not defined" error.
This error occurs when you try to validate an email field that is not defined
in your schema. To fix this error, make sure that your schema includes an
email field with the correct validation rules.

Conclusion

Validating email addresses is an important part of building a secure web
application. By using Mongoose schema validation, you can easily define rules
for your data, including email addresses. If you encounter any errors when
validating email addresses with Mongoose, make sure to check your schema and
validation rules.