Weeks In Year (ISO)
Gets the number of weeks in the current year, according to ISO weeks.
TIP
This requires the IsoWeeksInYear plugin to work
js
dayjs.extend(isoWeeksInYear);
dayjs.extend(isLeapYear);
dayjs('2004-01-01').isoWeeksInYear(); // 53
dayjs('2005-01-01').isoWeeksInYear(); // 52