Flarum\Event\ConfigureApiController::addInclude PHP Method

    public function addInclude($name)
    {
        $this->controller->include = array_merge($this->controller->include, (array) $name);
    }

 /**
  * @param ConfigureApiController $event
  */
 public function includeLikes(ConfigureApiController $event)
 {
     if ($event->isController(Controller\ShowDiscussionController::class)) {
         $event->addInclude('posts.likes');
     }
     if ($event->isController(Controller\ListPostsController::class) || $event->isController(Controller\ShowPostController::class) || $event->isController(Controller\CreatePostController::class) || $event->isController(Controller\UpdatePostController::class)) {
         $event->addInclude('likes');
     }
 }