Data validation based on rules
$validator = new class extends \Validator\Core\AbstractValidator {};
$validator->defineRules([
'username' => 'max(50):min(4)',
'other' => 'equals(:username)'
]);
$data = ['username' => 'Kanfa', 'other' => 'Other'];
if ($validator->validate($data)) {
// Action
} else {
$errors = $validator->getErrors();
// Error action
}