How to use the pouchdb-utils.hasLocalStorage function in pouchdb-utils

//   Mobile/9B206 Safari/7534.48.3
  // Firefox for iOS UA:
  //   Mozilla/5.0 (iPhone; CPU iPhone OS 8_3 like Mac OS X) AppleWebKit/600.1.4
  //   (KHTML, like Gecko) FxiOS/1.0 Mobile/12F69 Safari/600.1.4

  // indexedDB is null on some UIWebViews and undefined in others
  // see: https://bugs.webkit.org/show_bug.cgi?id=137034
  if (typeof indexedDB === 'undefined' || indexedDB === null ||
      !/iP(hone|od|ad)/.test(navigator.userAgent)) {
    // definitely not WKWebView, avoid creating an unnecessary database
    return true;
  }
  // Cache the result in LocalStorage. Reason we do this is because if we
  // call openDatabase() too many times, Safari craps out in SauceLabs and
  // starts throwing DOM Exception 14s.
  var hasLS = hasLocalStorage();
  // Include user agent in the hash, so that if Safari is upgraded, we don't
  // continually think it's broken.
  var localStorageKey = '_pouch__websqldb_valid_' + navigator.userAgent;
  if (hasLS && localStorage[localStorageKey]) {
    return localStorage[localStorageKey] === '1';
  }
  var openedTestDB = canOpenTestDB();
  if (hasLS) {
    localStorage[localStorageKey] = openedTestDB ? '1' : '0';
  }
  return openedTestDB;
}

function dbCreated() {
    // note the db name in case the browser upgrades to idb
    if (hasLocalStorage()) {
      window.localStorage['_pouch__websqldb_' + api._name] = true;
    }
    callback(null, api);
  }

adapter: match[1]
    };
  }

  var adapters = PouchDB.adapters;
  var preferredAdapters = PouchDB.preferredAdapters;
  var prefix = PouchDB.prefix;
  var adapterName = opts.adapter;

  if (!adapterName) { // automatically determine adapter
    for (var i = 0; i < preferredAdapters.length; ++i) {
      adapterName = preferredAdapters[i];
      // check for browsers that have been upgraded from websql-only to websql+idb
      /* istanbul ignore if */
      if (adapterName === 'idb' && 'websql' in adapters &&
          hasLocalStorage() && localStorage['_pouch__websqldb_' + prefix + name]) {
        // log it, because this can be confusing during development
        guardedConsole('log', 'PouchDB is downgrading "' + name + '" to WebSQL to' +
          ' avoid data loss, because it was already opened with WebSQL.');
        continue; // keep using websql to avoid user data loss
      }
      break;
    }
  }

  var adapter = adapters[adapterName];

  // if adapter is invalid, then an error will be thrown later
  var usePrefix = (adapter && 'use_prefix' in adapter) ?
    adapter.use_prefix : true;

  return {

req.onsuccess = function () {
      //Remove open request from the list.
      openReqList.delete(dbName);
      if (hasLocalStorage() && (dbName in localStorage)) {
        delete localStorage[dbName];
      }
      callback(null, { 'ok': true });
    };