Score.php

<?php

namespace Drupal\search\Plugin\views\field;

use Drupal\views\Plugin\views\field\NumericField;
use Drupal\views\ResultRow;

/**
 * Field handler for search score.
 *
 * @ingroup views_field_handlers
 *
 * @ViewsField("search_score")
 */
class Score extends NumericField {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        // Check to see if the search filter added 'score' to the table.
        // Our filter stores it as $handler->search_score -- and we also
        // need to check its relationship to make sure that we're using the same
        // one or obviously this won't work.
        foreach ($this->view->filter as $handler) {
            if (isset($handler->search_score) && $handler->relationship == $this->relationship) {
                $this->field_alias = $handler->search_score;
                $this->tableAlias = $handler->tableAlias;
                return;
            }
        }
        // Hide this field if no search filter is in place.
        $this->options['exclude'] = TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function render(ResultRow $values) {
        // Only render if we exist.
        if (isset($this->tableAlias)) {
            return parent::render($values);
        }
    }

}