tt_PREVWDAY function

dynamic tt_PREVWDAY(
  1. dynamic v1,
  2. dynamic v2
)

tt_PREVWDAY(date, dow): finds the previous occurrence of the given weekday before date

Implementation

dynamic tt_PREVWDAY(dynamic v1, dynamic v2) {
  final d = _vToDateTime(v1);
  if (d == null) return null;
  final target = varToInt(v2);
  var diff = d.weekday - target;
  if (diff <= 0) diff += 7;
  return d.subtract(Duration(days: diff));
}