async backup()

in src/js/background/sync.js [111:186]
16 lines of code
10 McCabe index (conditional complexity)

    async backup(options) {
      // remove listeners to avoid an infinite loop!
      await sync.checkForListenersMaybeRemove();

      const identities = await updateSyncIdentities();
      const siteAssignments = await updateSyncSiteAssignments();
      await updateInstanceInfo(identities, siteAssignments);
      if (options && options.uuid) 
        await this.deleteIdentity(options.uuid);
      if (options && options.undeleteUUID) 
        await removeFromDeletedIdentityList(options.undeleteUUID);
      if (options && options.siteStoreKey) 
        await this.deleteSite(options.siteStoreKey);
      if (options && options.undeleteSiteStoreKey) 
        await removeFromDeletedSitesList(options.undeleteSiteStoreKey);

      if (SYNC_DEBUG) console.log("Backed up!");
      await sync.checkForListenersMaybeAdd();

      async function updateSyncIdentities() {
        const identities = await browser.contextualIdentities.query({});

        for (const identity of identities) {
          delete identity.colorCode;
          delete identity.iconUrl;
          identity.macAddonUUID = await identityState.lookupMACaddonUUID(identity.cookieStoreId);
          if(identity.macAddonUUID) {
            const storageKey = "identity@@_" + identity.macAddonUUID;
            await sync.storageArea.set({ [storageKey]: identity });
          }
        }
        //await sync.storageArea.set({ identities });
        return identities;
      }

      async function updateSyncSiteAssignments() {
        const assignedSites = 
          await assignManager.storageArea.getAssignedSites();
        for (const siteKey of Object.keys(assignedSites)) {
          await sync.storageArea.set({ [siteKey]: assignedSites[siteKey] });
        }
        return assignedSites;
      }

      async function updateInstanceInfo(identitiesInput, siteAssignmentsInput) {
        const date = new Date();
        const timestamp = date.getTime();
        const installUUID = sync.storageArea.getInstanceKey();
        if (SYNC_DEBUG) console.log("adding", installUUID);
        const identities = [];
        const siteAssignments = [];
        for (const identity of identitiesInput) {
          identities.push(identity.macAddonUUID);
        }
        for (const siteAssignmentKey of Object.keys(siteAssignmentsInput)) {
          siteAssignments.push(siteAssignmentKey);
        }
        await sync.storageArea.set({ [installUUID]: { timestamp, identities, siteAssignments } });
      }

      async function removeFromDeletedIdentityList(identityUUID) {
        const deletedIdentityList = 
          await sync.storageArea.getDeletedIdentityList();
        const newDeletedIdentityList = deletedIdentityList
          .filter(element => element !== identityUUID);
        await sync.storageArea.set({ deletedIdentityList: newDeletedIdentityList });
      }

      async function removeFromDeletedSitesList(siteStoreKey) {
        const deletedSiteList = 
          await sync.storageArea.getDeletedSiteList();
        const newDeletedSiteList = deletedSiteList
          .filter(element => element !== siteStoreKey);
        await sync.storageArea.set({ deletedSiteList: newDeletedSiteList });
      }
    },