$date="2012-09-12";
if (preg_match("/^(20[0-9]{2})-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$date)) {
return true;
} else {
return false;
}
function isValidDate(string $date, string $format = 'Y-m-d'): bool
{
$dateObj = DateTime::createFromFormat($format, $date);
return $dateObj && $dateObj->format($format) == $date;
}