code: function isCacheValid (cache, fileHash, query) {
    // Verify that the source file is the same
    return cache.hash === fileHash &&
      // Verify that the options are the same
      cache.optionHash === generateHashForOptions(query) &&
      // Verify that the favicons version of the cache maches this version
      cache.version === pluginVersion;
  }
docs: Checks if the given cache object is still valid