   ts.convertFormat = function( dateString, format ) {
      dateString = ( dateString || '' )
       .replace( ts.regex.spaces, ' ' )
       .replace( ts.regex.shortDateReplace, '/' );
      if ( format === 'mmddyyyy' ) {
         dateString = dateString.replace( ts.regex.shortDateXXY, '$3/$1/$2' );
      } else if ( format === 'ddmmyyyy' ) {
         dateString = dateString.replace( ts.regex.shortDateXXY, '$3/$2/$1' );
      } else if ( format === 'yyyymmdd' ) {
         dateString = dateString.replace( ts.regex.shortDateYMD, '$1/$2/$3' );
      }
      var date = new Date( dateString );
      return date instanceof Date && isFinite( date ) ? date.getTime() : '';
   };