class LinkSeparateFormatter

class LinkSeparateFormatter extends LinkFormatter {
    
    /**
     * {@inheritdoc}
     */
    public static function defaultSettings() {
        return [
            'trim_length' => 80,
            'rel' => '',
            'target' => '',
        ] + parent::defaultSettings();
    }
    
    /**
     * {@inheritdoc}
     */
    public function viewElements(FieldItemListInterface $items, $langcode) {
        $element = [];
        $entity = $items->getEntity();
        $settings = $this->getSettings();
        foreach ($items as $delta => $item) {
            // By default use the full URL as the link text.
            $url = $this->buildUrl($item);
            $link_title = $url->toString();
            // If the link text field value is available, use it for the text.
            if (empty($settings['url_only']) && !empty($item->title)) {
                // Unsanitized token replacement here because the entire link title
                // gets auto-escaped during link generation in
                // \Drupal\Core\Utility\LinkGenerator::generate().
                $link_title = \Drupal::token()->replace($item->title, [
                    $entity->getEntityTypeId() => $entity,
                ], [
                    'clear' => TRUE,
                ]);
            }
            // The link_separate formatter has two titles; the link text (as in the
            // field values) and the URL itself. If there is no link text value,
            // $link_title defaults to the URL, so it needs to be unset.
            // The URL version may need to be trimmed as well.
            if (empty($item->title)) {
                $link_title = NULL;
            }
            $url_title = $url->toString();
            if (!empty($settings['trim_length'])) {
                $link_title = $link_title !== NULL ? Unicode::truncate($link_title, $settings['trim_length'], FALSE, TRUE) : NULL;
                $url_title = Unicode::truncate($url_title, $settings['trim_length'], FALSE, TRUE);
            }
            $element[$delta] = [
                '#theme' => 'link_formatter_link_separate',
                '#title' => $link_title,
                '#url_title' => $url_title,
                '#url' => $url,
            ];
            if (!empty($item->_attributes)) {
                // Set our attributes on the <a> element that is being built.
                $url->setOption('attributes', $item->_attributes);
                // Unset field item attributes since they have been included in the
                // formatter output and should not be rendered in the field template.
                unset($item->_attributes);
            }
        }
        return $element;
    }

}