Drupal 8 - Example of adding dynamic js libraries which require locale

my_module.module

/**
 * Implements hook_library_info_build().
 *
 * @return array
 */
function mymodule_library_info_build() {
  $libraries = [];
  
  $api_key = \Drupal::config('mymodule.api_key');

  $libraries['mymodule.map'] = [
    'js' => [
      'https://www.googleapis.com/geolocation/v1/geolocate?key=' . $api_key => [],
    ],
  ];

  return $libraries;
}

/**
 * Implements hook_page_attachments().
 */
function mymodule_page_attachments(array &$page) {
  $page['#attached']['library'][] = 'mymodule/map';
}