Method ensureInitialized

packages/service-worker/worker/src/driver.ts:374–398

(event: ExtendableEvent)

  }

  private async ensureInitialized(event: ExtendableEvent): Promise<void> {
    // Since the SW may have just been started, it may or may not have been initialized already.
    // `this.initialized` will be `null` if initialization has not yet been attempted, or will be a
    // `Promise` which will resolve (successfully or unsuccessfully) if it has.
    if (this.initialized !== null) {
      return this.initialized;
    }

    // Initialization has not yet been attempted, so attempt it. This should only ever happen once
    // per SW instantiation.
    try {
      this.initialized = this.initialize();
      await this.initialized;
    } catch (error) {
      // If initialization fails, the SW needs to enter a safe state, where it declines to respond
      // to network requests.
      this.state = DriverReadyState.SAFE_MODE;
      this.stateMessage = `Initialization failed due to error: ${errorToString(error)}`;

      throw error;
    } finally {
      // Regardless if initialization succeeded, background tasks still need to happen.
      event.waitUntil(this.idle.trigger());
    }
  }

  private async handleMessage(msg: MsgAny & {action: string}, from: Client): Promise<void> {
    if (isMsgCheckForUpdates(msg)) {