code: function(d) {
      return d.wmStart || (d.wmStart = later.date.next(
        later.Y.val(d),
        later.M.val(d),
        Math.max(later.D.val(d) - later.dw.val(d) + 1, 1)));
    }
docs: The start of the week of the specified date.
  
  @param {Date} d: The specified date