code: function prettyDate (time, useCompactFormat, maxDiff) {
          maxDiff = maxDiff || 86400 * 10; // default = 10 days
  
          switch (time.constructor) {
          case String: // timestamp
              time = parseInt(time);
              break;
          case Date:
              time = time.getTime();
              break;
          }
  
          var secDiff = (Date.now() - time) / 1000;
          if (isNaN(secDiff)) {
              return _('incorrectDate');
          }
  
          if (Math.abs(secDiff) > 60) {
              // round milliseconds up if difference is over 1 minute so the result is
              // closer to what the user would expect (1h59m59s300ms diff should return
              // "in 2 hours" instead of "in an hour")
              secDiff = secDiff > 0 ? Math.ceil(secDiff) : Math.floor(secDiff);
          }
  
          if (secDiff > maxDiff) {
              return localeFormat(new Date(time), '%x');
          }
  
          var f = useCompactFormat ? '-short' : '-long';
          var parts = relativeParts(secDiff);
  
          var affix = secDiff >= 0 ? '-ago' : '-until';
          for (var i in parts) {
              return _(i + affix + f, { value: parts[i] });
          }
      }
docs: Returns a translated string which respresents the
  relative time before or after a date.
  @param {String|Date} time before/after the currentDate.
  @param {String} useCompactFormat whether to use a compact display format.
  @param {Number} maxDiff returns a formatted date if the diff is greater.