public static DateTimePlus::prepareArray($array, $force_valid_date = FALSE)

protected DateTimePlus::prepareFormat($format)

protected DateTimePlus::prepareTime($time)

The prepared timezone object used to construct this date. File core/lib/Drupal/Component/Datetime/DateTimePlus

public static DateHelper::dayOfWeek($date = NULL)

public DateFormatterInterface::format($timestamp,

public static Datetime::valueCallback(&$element, $input, FormStateInterface

public static Datetime::processDatetime(&$element, FormStateInterface

public DateFormatterInterface::formatInterval($interval

public static DateHelper::weekDays($required = FALSE)