code: function format(timestamp, acceptLanguageHeader) {
        if (! timestamp) {
          return '';
        }
        // create a new moment from a timestamp
        var lastAccessTime = moment(timestamp);
        var language = defaultLanguage;
        try {
          if (acceptLanguageHeader) {
            var parseHeader = acceptLanguage.parse(acceptLanguageHeader);
            // parse should return an Array of parsed languages in priority order based on the `acceptLanguageHeader`.
            if (parseHeader && Array.isArray(parseHeader) && parseHeader.length > 0 && parseHeader[0].language) {
              // the 'accept-language' will fallback to unsupported locale if it cannot find anything
              // we do not want that, only set language if it is a supported locale.
              if (supportedLanguages.indexOf(parseHeader[0].language) !== -1) {
                language = parseHeader[0].language;
              }
            }
          }
        } catch (e) {
          // failed to parse the header, fallback to defaultLanguage
        }
  
        // set the moment locale to determined `language`.
        lastAccessTime.locale(language);
        // return a formatted `timeago` type string
        return lastAccessTime.fromNow();
      }
docs: Convert a given `timestamp` to a moment 'time from now' format
  based on a given `acceptLanguage`.
  Docs: http://momentjs.com/docs/#/displaying/fromnow/
  
  @param {Number} timestamp
  @param {String} acceptLanguageHeader
  @returns {String} Returns a localized string based on a given timestamp.
  Returns an empty string if no timestamp provided.