code: function(gzipEncoding) {
        var gzipSettings = gzipEncoding || {};
        var { whitelist, blacklist } = Object.keys(gzipSettings).reduce((prev, key) => {
          if (gzipSettings[key]) {
            prev['whitelist'].push(key);
          } else {
            prev['blacklist'].push(key);
          }
          return prev;
        }, { whitelist: [], blacklist: [] });
  
        // @NOTE - we REMOVE whitelisted types from the blacklist array
        var gzipBlacklist = defaultGzipBlacklist.concat(blacklist).filter(el => whitelist.indexOf(el));
  
        return _.uniq(gzipBlacklist);
      }
docs: Use sane defaults and user config to get array of file extensions to avoid gzipping
  @param gzipEncoding {Object} ex: {jpg: true, rando: false}
  @retyrb {Array} An array of file extensions to ignore