How to exclude the current node from a view display in drupal 8

exclude_current_node_from_view.php

function YOUR_MODULE_views_query_alter(ViewExecutable $view, QueryPluginBase $query) {  
  if ($view->id() == 'name_of_your_view') {
    $node = \Drupal::routeMatch()->getParameter('node');
    if ($node instanceof NodeInterface) {
      // You can get nid and anything else you need from the node object.
      $nid = $node->id();

      $query
        ->addWhere(0, db_and()
          ->condition('node_field_data.nid', $nid, '!='));
    }
  }
}