Method lookupResourceWithHash

packages/service-worker/worker/src/driver.ts:1167–1189

* Determine if a specific version of the given resource is cached anywhere within the SW, * and fetch it if so.

(url: NormalizedUrl, hash: string)

   * and fetch it if so.
   */
  lookupResourceWithHash(url: NormalizedUrl, hash: string): Promise<Response | null> {
    return (
      Array
        // Scan through the set of all cached versions, valid or otherwise. It's safe to do such
        // lookups even for invalid versions as the cached version of a resource will have the
        // same hash regardless.
        .from(this.versions.values())
        // Reduce the set of versions to a single potential result. At any point along the
        // reduction, if a response has already been identified, then pass it through, as no
        // future operation could change the response. If no response has been found yet, keep
        // checking versions until one is or until all versions have been exhausted.
        .reduce(async (prev, version) => {
          // First, check the previous result. If a non-null result has been found already, just
          // return it.
          if ((await prev) !== null) {
            return prev;
          }

          // No result has been found yet. Try the next `AppVersion`.
          return version.lookupResourceWithHash(url, hash);
        }, Promise.resolve<Response | null>(null))
    );
  }

  async lookupResourceWithoutHash(url: NormalizedUrl): Promise<CacheState | null> {
    await this.initialized;