code: function getDateDifference(timestr1, timestr2) {
  	// Force into predictable date format
  	var start = timestr1.toLocaleDateString ? timestr1 : new Date(timestr1);
  	var end = timestr2.toLocaleDateString ? timestr2 : new Date(timestr2);
  
  	if (start.toString() === 'Invalid Date' || end.toString() === 'Invalid Date') {
  		throw new TypeError('pendel.date() expects two valid date strings');
  	}
  
  	var dr = moment.range(start, end);
  
  	return {
  		years: dr.diff('years'),
  		months: dr.diff('months'),
  		weeks: dr.diff('weeks'),
  		days: dr.diff('days'),
  		hours: dr.diff('hours'),
  		minutes: dr.diff('minutes'),
  		seconds: dr.diff('seconds')
  	};
  }
docs: Get the time difference between two datestrings.
  
  @param {string} timestr1 - a date string.
  @param {string} timestr2 - a date string.
  @returns {object}