cm_data_layer.module

<?php

/**
 * Implements hook_page_attachments().
 */
function cm_data_layer_page_attachments(array &$page) {
  $page['#attached']['library'][] = "cm_data_layer/data_layer_push_command";
}

/**
 * Implements hook_user_login().
 */
function cm_data_layer_user_login($account) {
  \Drupal::service('cm_data_layer.data_layer')->migrateAnonData();
}