ServiceWorkerHelper.ts

import Log from '../libraries/Log';
import Path from '../models/Path';
import { InvalidStateError, InvalidStateReason } from '../errors/InvalidStateError';
import { OneSignalUtils } from '../utils/OneSignalUtils';

export default class ServiceWorkerHelper {
  // Gets details on the service-worker (if any) that controls the current page
  public static async getRegistration(): Promise<ServiceWorkerRegistration | null | undefined> {
    try {
      // location.href is used for <base> tag compatibility when it is set to a different origin
      return await navigator.serviceWorker.getRegistration(location.href);
    } catch (e) {
      // This could be null in an HTTP context or error if the user doesn't accept cookies
      Log.warn("[Service Worker Status] Error Checking service worker registration", location.href, e);
      return null;
    }
  }

  public static getServiceWorkerHref(
    workerState: ServiceWorkerActiveState,
    config: ServiceWorkerManagerConfig): string {
    let workerFullPath = "";

    // Determine which worker to install
    if (workerState === ServiceWorkerActiveState.WorkerA)
      workerFullPath = config.workerBPath.getFullPath();
    else if (workerState === ServiceWorkerActiveState.WorkerB ||
      workerState === ServiceWorkerActiveState.ThirdParty ||
      workerState === ServiceWorkerActiveState.None)
      workerFullPath = config.workerAPath.getFullPath();
    else if (workerState === ServiceWorkerActiveState.Bypassed) {
      /*
        if the page is hard refreshed bypassing the cache, no service worker
        will control the page.

        It doesn't matter if we try to reinstall an existing worker; still no
        service worker will control the page after installation.
       */
      throw new InvalidStateError(InvalidStateReason.UnsupportedEnvironment);
    }

    return new URL(workerFullPath, OneSignalUtils.getBaseUrl()).href;
  }
}

export enum ServiceWorkerActiveState {
  /**
   * OneSignalSDKWorker.js, or the equivalent custom file name, is active.
   */
  WorkerA = 'Worker A (Main)',
  /**
   * OneSignalSDKUpdaterWorker.js, or the equivalent custom file name, is
   * active.
   *
   * We no longer need to use this filename. We can update Worker A by appending
   * a random query parameter to A.
   */
  WorkerB = 'Worker B (Updater)',
  /**
   * A service worker is active, but it is neither OneSignalSDKWorker.js nor
   * OneSignalSDKUpdaterWorker.js (or the equivalent custom file names as
   * provided by user config).
   */
  ThirdParty = '3rd Party',
  /**
   * A service worker is currently installing and we can't determine its final state yet. Wait until
   * the service worker is finished installing by checking for a controllerchange property..
   */
  Installing = 'Installing',
  /**
   * No service worker is installed.
   */
  None = 'None',
  /**
   * A service worker is active but not controlling the page. This can occur if
   * the page is hard-refreshed bypassing the cache, which also bypasses service
   * workers.
   */
  Bypassed = 'Bypassed',
  /**
   * Service workers are not supported in this environment. This status is used
   * on HTTP pages where it isn't possible to know whether a service worker is
   * installed or not or in any of the other states.
   */
  Indeterminate = 'Indeterminate'
}

export interface ServiceWorkerManagerConfig {
  /**
   * The path and filename of the "main" worker (e.g. '/OneSignalSDKWorker.js');
   */
  workerAPath: Path;
  /**
   * The path and filename to the "alternate" worker, used to update an existing
   * service worker. (e.g. '/OneSignalSDKUpdaterWorer.js')
   */
  workerBPath: Path;
  /**
   * Describes how much of the origin the service worker controls.
   * This is currently always "/".
   */
  registrationOptions: { scope: string };
}