Drupal - Why is my Datetime field not saved?

The above code is correct, date time was saved into DB. the problem is frontend.

frontend expected this format:

"2016-08-01T12:30:00", need a "T" as separator.

here is how to put that T as separator,

\DateTime::format("Y-m-d\Th:i:s"), need a escape character in-front of T.

2016-01-22 update:

By the way, I have found out in Drupal 8 , correct way to store datetime is follow:

1> first , find out current user timezone, \Drupal::currentUser()->getTimezone()

2> $given = new \Drupal\Core\Datetime\DrupalDateTime("2016-08-01T12:30:00",$user->getTimezone());

3> $given->setTimezone(new \DateTimeZone("UTC"));

4> then get back formated datetime string $given->format("Y-m-d\Th:i:s");

I had the same problem, please try this

$dateTime = \DateTime::createFromFormat('Y-m-d','2000-01-30');
$newDateString = $dateTime->format('Y-m-d\TH:i:s');
$node = \Drupal\node\Entity\Node::create(array(
          'type' => 'article',
          'title' => 'The title',
          'langcode' => 'en',
          'uid' => 1,
          'status' => 1,
          'body' => array('The body text'),
          //'field_date' => array("2000-01-30"),
          'field_date' => $newDateString,
    ));
$node->save();

I've picked it from here:https://www.drupal8.ovh/en/tutoriels/64/create-a-node-date-field

I hope it helps you.