Function utcWeekNum

docs/tests/v2/es6/js/sanddance.js:92243–92246

(d)

};

function utcWeekNum(d) {
  const y = Date.UTC(d.getUTCFullYear(), 0, 1);
  return _d3Time.utcWeek.count(y - 1, d);
}

function utcFirst(y) {
  t0.setTime(Date.UTC(y, 0, 1));