<% function getCalendarWeek(dateStr) { const date = new Date(dateStr); const d = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate())); const dayNum = d.getUTCDay() || 7; d.setUTCDate(d.getUTCDate() + 4 - dayNum); const yearStart = new Date(Date.UTC(d.getUTCFullYear(), 0, 1)); const weekNo = Math.ceil((((d - yearStart) / 86400000) + 1) / 7); return weekNo; } const calendarWeek = getCalendarWeek(week.week_start); %> Kalenderwoche <%= String(calendarWeek).padStart(2, '0') %>: <%= new Date(week.week_start).toLocaleDateString('de-DE') %> - <%= new Date(week.week_end).toLocaleDateString('de-DE') %>