HtmxTestAttachmentsController.php

<?php

declare (strict_types=1);
namespace Drupal\test_htmx\Controller;

use Drupal\Core\Controller\ControllerBase;
use Drupal\Core\Url;

/**
 * Returns responses for HTMX Test Attachments routes.
 */
final class HtmxTestAttachmentsController extends ControllerBase {
    
    /**
     * Builds the response.
     *
     * @return mixed[]
     *   A render array.
     */
    public function page() : array {
        return self::generateHtmxButton();
    }
    
    /**
     * Builds the HTMX response.
     *
     * @return mixed[]
     *   A render array.
     */
    public function replace() : array {
        $build['content'] = [
            '#type' => 'container',
            '#attached' => [
                'library' => [
                    'test_htmx/assets',
                ],
            ],
            '#attributes' => [
                'class' => [
                    'ajax-content',
                ],
            ],
            'example' => [
                '#markup' => 'Initial Content',
            ],
        ];
        return $build;
    }
    
    /**
     * Static helper to for reusable render array.
     *
     * @return array
     *   The render array.
     */
    public static function generateHtmxButton() : array {
        $url = Url::fromRoute('test_htmx.attachments.replace');
        $build['replace'] = [
            '#type' => 'html_tag',
            '#tag' => 'button',
            '#attributes' => [
                'type' => 'button',
                'name' => 'replace',
                'data-hx-get' => $url->toString(),
                'data-hx-select' => 'div.ajax-content',
                'data-hx-target' => '[data-drupal-htmx-target]',
            ],
            '#value' => 'Click this',
            '#attached' => [
                'library' => [
                    'core/drupal.htmx',
                ],
            ],
        ];
        $build['content'] = [
            '#type' => 'container',
            '#attributes' => [
                'data-drupal-htmx-target' => TRUE,
                'class' => [
                    'htmx-test-container',
                ],
            ],
        ];
        return $build;
    }

}