buildDate example

'operator' => RuleConstraints::datetimeOperators(false),
        ];
    }

    public function match(RuleScope $scope): bool
    {
        if ($this->lineItemCreationDate === null) {
            return false;
        }

        try {
            $ruleValue = $this->buildDate($this->lineItemCreationDate);
        } catch (\Exception) {
            return false;
        }

        if ($scope instanceof LineItemScope) {
            return $this->matchesCreationDate($scope->getLineItem(), $ruleValue);
        }

        if (!$scope instanceof CartRuleScope) {
            return false;
        }

        

return $constraints;
        }

        $constraints['lineItemReleaseDate'] = RuleConstraints::datetime();

        return $constraints;
    }

    public function match(RuleScope $scope): bool
    {
        try {
            $ruleValue = $this->buildDate($this->lineItemReleaseDate);
        } catch (\Exception) {
            return false;
        }

        if ($scope instanceof LineItemScope) {
            return $this->matchesReleaseDate($scope->getLineItem(), $ruleValue);
        }

        if (!$scope instanceof CartRuleScope) {
            return false;
        }

        

$separator = $this->getSetting('separator');

    foreach ($items as $delta => $item) {
      if (!empty($item->start_date) && !empty($item->end_date)) {
        /** @var \Drupal\Core\Datetime\DrupalDateTime $start_date */
        $start_date = $item->start_date;
        /** @var \Drupal\Core\Datetime\DrupalDateTime $end_date */
        $end_date = $item->end_date;

        if ($start_date->getTimestamp() !== $end_date->getTimestamp()) {
          $elements[$delta] = [
            'start_date' => $this->buildDate($start_date),
            'separator' => ['#plain_text' => ' ' . $separator . ' '],
            'end_date' => $this->buildDate($end_date),
          ];
        }
        else {
          $elements[$delta] = $this->buildDate($start_date);
        }
      }
    }

    return $elements;
  }

$separator = $this->getSetting('separator');

    foreach ($items as $delta => $item) {
      if (!empty($item->start_date) && !empty($item->end_date)) {
        /** @var \Drupal\Core\Datetime\DrupalDateTime $start_date */
        $start_date = $item->start_date;
        /** @var \Drupal\Core\Datetime\DrupalDateTime $end_date */
        $end_date = $item->end_date;

        if ($start_date->getTimestamp() !== $end_date->getTimestamp()) {
          $elements[$delta] = [
            'start_date' => $this->buildDate($start_date),
            'separator' => ['#plain_text' => ' ' . $separator . ' '],
            'end_date' => $this->buildDate($end_date),
          ];
        }
        else {
          $elements[$delta] = $this->buildDate($start_date);

          if (!empty($item->_attributes)) {
            $elements[$delta]['#attributes'] += $item->_attributes;
            // Unset field item attributes since they have been included in the             // formatter output and should not be rendered in the field template.

/** * {@inheritdoc} */
  public function viewElements(FieldItemListInterface $items, $langcode) {
    $elements = [];

    foreach ($items as $delta => $item) {
      if (!empty($item->date)) {
        /** @var \Drupal\Core\Datetime\DrupalDateTime $date */
        $date = $item->date;

        $elements[$delta] = $this->buildDate($date);
      }
    }

    return $elements;
  }

  /** * {@inheritdoc} */
  protected function formatDate($date) {
    $format = $this->getFieldSetting('datetime_type') == DateTimeItem::DATETIME_TYPE_DATE ? DateTimeItemInterface::DATE_STORAGE_FORMAT : DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
    

public function viewElements(FieldItemListInterface $items, $langcode) {
    // @todo Evaluate removing this method in     // https://www.drupal.org/node/2793143 to determine if the behavior and     // markup in the base class implementation can be used instead.     $elements = [];

    foreach ($items as $delta => $item) {
      if (!empty($item->date)) {
        /** @var \Drupal\Core\Datetime\DrupalDateTime $date */
        $date = $item->date;

        $elements[$delta] = $this->buildDate($date);
      }
    }

    return $elements;
  }

  /** * {@inheritdoc} */
  protected function formatDate($date) {
    $format = $this->getSetting('date_format');