class ChangedCommand

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,
        ];
    }

}