Drupal 8 #attached not working inside eventsubscriber - drupal

Question

Hi All below Drupal 8 EventSubscriber class supposed to attach drupalSettings into Drupal 8 javascript settings. But unfortunately this \Drupal::service('renderer')->renderRoot($js_data); not attaching the drupal javascript settings.
namespace Drupal\ejectorseat\EventSubscriber;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\HttpKernel\KernelEvents;
use Drupal\Core\Url;
class EjectorseatSubscriber implements EventSubscriberInterface {
public function customEjector(GetResponseEvent $event) {
$account = \Drupal::currentUser();
$ejectorseat_interval = \Drupal::config('ejectorseat.settings')->get('ejectorseat_interval');
if(empty($ejectorseat_interval)){
$ejectorseat_interval = 60;
}
$ejectorseat_background = \Drupal::config('ejectorseat.settings')->get('ejectorseat_background');
if(empty($ejectorseat_background)){
$ejectorseat_background = 0;
}
if ($account->id() > 0 && (int) $ejectorseat_interval) {
$js_data = array();
$js_data['#attached']['drupalSettings']['ejectorSeat']['interval'] = $ejectorseat_interval;
$js_data['#attached']['drupalSettings']['ejectorSeat']['url'] = Url::fromRoute('ejectorseat/check');
$js_data['#attached']['drupalSettings']['ejectorSeat']['ignoreFocus'] = $ejectorseat_background ? TRUE : FALSE;
\Drupal::service('renderer')->renderRoot($js_data);
}
}
public static function getSubscribedEvents() {
$events[KernelEvents::REQUEST][] = array('customEjector');
return $events;
}
}

Answer 1

I was facing the same issue and i didn't find a OOP solution.
In your case just place your logic form the customEjector Method in a HOOK called hook_js_settings_alter in your ejectorseat.module file. This way you can be sure all variables are avaiable in the drupalSettings Object.
E.g just for demonstration:
<?php
/**
* Implements hook_js_settings_alter().
*
*/
function ejectorseat_js_settings_alter(array &$settings,
\Drupal\Core\Asset\AttachedAssetsInterface $assets
) {
...
$settings['all_settings'] = $globalSettings->getAll();
//if you want to push only a single value
$settings['custom_link'] = $globalSettings->get('custom_link')
$settings['ejectorSeat']['interval'] = $ejectorseat_interval;
$settings['ejectorSeat']['url'] = Url::fromRoute('ejectorseat/check');
$settings['ejectorSeat']['ejectorSeat']['ignoreFocus'] = $ejectorseat_background ? TRUE : FALSE;
}