How to use flat-cache

async getAddress(locationObject) {
    const cacheKey = `${String(+locationObject.lat.toFixed(3))}-${String(+locationObject.lon.toFixed(3))}`
    const cachedResult = geoCache.getKey(cacheKey)
    if (cachedResult) return cachedResult

    try {
      const geocoder = this.getGeocoder()
      const [result] = await geocoder.reverse(locationObject)
      const flag = emojiFlags[result.countryCode]
      const addressDts = this.mustache.compile(this.config.locale.addressFormat)
      result.addr = addressDts(result)
      result.flag = flag ? flag.emoji : ''
      geoCache.setKey(cacheKey, result)
      geoCache.save(true)
      return result
    } catch (err) {
      throw new Error({ source: 'getAddress', error: err })
    }
  }

let cache = flatCache.load(`${cacheHash}`, path.resolve(options.cacheDir));
if (cache._persisted.data === undefined || Object.keys(cache._persisted).length == 0) {
 (options.verbose) ? console.log(chalk.bold.green('✅    INFO:: Cache is empty, fetching data from GitHub')) : null;
 return fetch_starred_repos(options, pages)
  .then((data) => {
   cache.setKey('data', data);
   cache.save();
   return data;
  });
} else {
 (options.verbose) ? console.log(chalk.bold.red('⚠️    INFO:: Serving search results from cache')) : null;
 return cache.getKey('data');