How to properly write email validation?

Question

PHP

Validation for the field Name (contact) is registered in the module controller

if ((utf8_strlen($this->request->post['contact']) < 3) || (utf8_strlen($this->request->post['contact']) > 100)) {
$json['error']['contact'] = $this->language->get('error_contact');
}

You need to add validation for the email field using a regular expression.

Answer 1

php.net/manual/en/filter.examples.validation.php

if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
    echo "E-mail ($email_a) указан верно.";
}

Answer 2

Googling once or twice.
Here is an interesting way, by the way, without regular expressions:

if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
    // invalid emailaddress
}