Hide an exposed filter block if the view results are empty

/**
* Implements hook_views_pre_render().
*/
function mymodule_views_pre_render(ViewExecutable $view) {
 if ($view->storage->id() == 'myview' && $view->current_display == 'block_1') {
   if (empty($view->result) && empty($view->getExposedInput())) {
     $view->exposed_widgets = NULL;
   }
 }
}