fontawesome-8.x-2.x-dev/modules/fontawesome_iconpicker_widget/fontawesome_iconpicker_widget.module

<?php

/**
 * @file
 * Module for integration of iconpicker with Font Awesome.
 */

/**
 * Check to make sure that the iconpicker library is installed.
 *
 * @return bool
 *   Flag indicating if the library is properly installed.
 */
function fontawesome_iconpicker_widget_check_installed() {
  $iconpicker_library = \Drupal::service('library.discovery')->getLibraryByName('fontawesome_iconpicker_widget', 'fonticonpicker');
  return file_exists(DRUPAL_ROOT . '/' . $iconpicker_library['js'][0]['data']);
}