NodeRow.php

<?php

namespace Drupal\node\Plugin\views\row;

use Drupal\views\Plugin\views\row\EntityRow;

/**
 * Plugin which performs a node_view on the resulting object.
 *
 * Most of the code on this object is in the theme function.
 *
 * @ingroup views_row_plugins
 *
 * @ViewsRow(
 *   id = "entity:node",
 * )
 */
class NodeRow extends EntityRow {
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['view_mode']['default'] = 'teaser';
        return $options;
    }

}