AjaxResponse.php

<?php

namespace Drupal\Core\Ajax;

use Drupal\Core\Render\BubbleableMetadata;
use Drupal\Core\Render\AttachmentsInterface;
use Drupal\Core\Render\AttachmentsTrait;
use Symfony\Component\HttpFoundation\JsonResponse;

/**
 * JSON response object for AJAX requests.
 *
 * @ingroup ajax
 */
class AjaxResponse extends JsonResponse implements AttachmentsInterface {
    use AttachmentsTrait;
    
    /**
     * The array of ajax commands.
     *
     * @var array
     */
    protected $commands = [];
    
    /**
     * Add an AJAX command to the response.
     *
     * @param \Drupal\Core\Ajax\CommandInterface $command
     *   An AJAX command object implementing CommandInterface.
     * @param bool $prepend
     *   A boolean which determines whether the new command should be executed
     *   before previously added commands. Defaults to FALSE.
     *
     * @return $this
     *   The current AjaxResponse.
     */
    public function addCommand(CommandInterface $command, $prepend = FALSE) {
        if ($prepend) {
            array_unshift($this->commands, $command->render());
        }
        else {
            $this->commands[] = $command->render();
        }
        if ($command instanceof CommandWithAttachedAssetsInterface) {
            $assets = $command->getAttachedAssets();
            $attachments = [
                'library' => $assets->getLibraries(),
                'drupalSettings' => $assets->getSettings(),
            ];
            $attachments = BubbleableMetadata::mergeAttachments($this->getAttachments(), $attachments);
            $this->setAttachments($attachments);
        }
        return $this;
    }
    
    /**
     * Gets all AJAX commands.
     *
     * @return array
     *   Returns render arrays for all previously added commands.
     */
    public function &getCommands() {
        return $this->commands;
    }

}