system_js_settings_build

system_js_settings_build(&$settings, AttachedAssetsInterface $assets)

function system_js_settings_build(&$settings, AttachedAssetsInterface $assets) {
  // Generate the values for the core/drupal.ajax library.
  // We need to send ajaxPageState settings for core/drupal.ajax if:
  // - ajaxPageState is being loaded in this Response, in which case it will
  //   already exist at $settings['ajaxPageState'] (because the core/drupal.ajax
  //   library definition specifies a placeholder 'ajaxPageState' setting).
  // - core/drupal.ajax already has been loaded and hence this is an AJAX
  //   Response in which we must send the list of extra asset libraries that are
  //   being added in this AJAX Response.
  /** @var \Drupal\Core\Asset\LibraryDependencyResolver $library_dependency_resolver */
  $library_dependency_resolver = \Drupal::service('library.dependency_resolver');
  if (isset($settings['ajaxPageState']) || in_array('core/drupal.ajax', $library_dependency_resolver->getLibrariesWithDependencies($assets->getAlreadyLoadedLibraries()))) {
    // Provide the page with information about the theme that's used, so that
    // a later AJAX request can be rendered using the same theme.
    // @see \Drupal\Core\Theme\AjaxBasePageNegotiator
    $theme_key = \Drupal::theme()->getActiveTheme()->getName();
    $settings['ajaxPageState']['theme'] = $theme_key;
  }
}