nl_tokens: weeksSince won t work here as the result needs to be floored not rounded .
pl_tokens: function getWeekNumber ( date ) { date = date . <mask> ( ) ; var dow = callDateGet ( date , 'Day' ) || 7 ; date . addDays ( 4 - dow ) . reset ( ) ; return 1 + floor ( date . daysSince ( date . clone ( ) . beginningOfYear ( ) ) / 7 ) ; }