date_recur-8.x-2.2/src/Plugin/Validation/Constraint/DateRecurTimeZoneConstraintValidator.php

<?php

declare(strict_types=1);

namespace Drupal\date_recur\Plugin\Validation\Constraint;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

/**
 * Validates the DateRecurTimeZone constraint.
 */
class DateRecurTimeZoneConstraintValidator extends ConstraintValidator {

  /**
   * {@inheritdoc}
   */
  public function validate($value, Constraint $constraint) {
    \assert($constraint instanceof DateRecurTimeZoneConstraint);
    $timeZones = \DateTimeZone::listIdentifiers();
    if (\is_string($value) && !\in_array($value, $timeZones, TRUE)) {
      $this->context->addViolation($constraint->invalidTimeZone, ['%value' => $value]);
    }
  }

}