<?php

namespace Drupal\Core\Ajax;

/**
 * An AJAX command for marking HTML elements as changed.
 *
 * This command instructs the client to mark each of the elements matched by the
 * given selector as 'ajax-changed'.
 *
 * This command is implemented by Drupal.AjaxCommands.prototype.changed()
 * defined in misc/ajax.js.
 *
 * @ingroup ajax
 */
class ChangedCommand implements CommandInterface {

  /**
   * A CSS selector string.
   *
   * If the command is a response to a request from an #ajax form element then
   * this value can be NULL.
   *
   * @var string
   */
  protected $selector;

  /**
   * An optional CSS selector for elements to which asterisks will be appended.
   *
   * @var string
   */
  protected $asterisk;

  /**
   * Constructs a ChangedCommand object.
   *
   * @param string $selector
   *   CSS selector for elements to be marked as changed.
   * @param string $asterisk
   *   CSS selector for elements to which an asterisk will be appended.
   */
  public function __construct($selector, $asterisk = '') {
    $this->selector = $selector;
    $this->asterisk = $asterisk;
  }

  /**
   * Implements Drupal\Core\Ajax\CommandInterface:render().
   */
  public function render() {

    return [
      'command' => 'changed',
      'selector' => $this->selector,
      'asterisk' => $this->asterisk,
    ];
  }

}