text: define(function () {
  
      /**
       * convert time into another unit
       */
      function convert(val, sourceUnitName, destinationUnitName){
  	destinationUnitName = destinationUnitName || 'ms';
  	return (val * getUnit(sourceUnitName)) / getUnit(destinationUnitName);
      }
  
  
      //TODO: maybe extract to a separate module
      function getUnit(unitName){
  	switch(unitName){
  	    case 'ms':
  	    case 'millisecond':
  		return 1;
  	    case 's':
  	    case 'second':
  		 return 1000;
  	    case 'm':
  	    case 'minute':
  		 return 60000;
  	    case 'h':
  	    case 'hour':
  		 return 3600000;
  	    case 'd':
  	    case 'day':
  		 return 86400000;
  	    case 'w':
  	    case 'week':
  		 return 604800000;
  	    default:
  		throw new Error('"'+ unitName + '" is not a valid unit');
  	}
      }
  
  
      return convert;
  
  });
  