- var_dump: documentation ( source)
<?php
$DateTime = new \DateTime('2018-5-30');
$formatter = new IntlDateFormatter('en-US', IntlDateFormatter::SHORT, IntlDateFormatter::NONE, 'Europe/Berlin');
$format = $formatter->getPattern();
echo $format . "\r\n";
$formattedDateTime = $formatter->format($DateTime);
echo $formattedDateTime . "\r\n";
$date = DateTime::createFromFormat($format, $formattedDateTime);
var_dump($date);
var_dump(DateTime::getLastErrors());
echo $date->format('Y-m-d');