src/constraint/weekofmonth.js
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)));
  }
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)));
  }
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 ) ) ) ; }
The start of the week of the specified date.

@param {Date} d: The specified date
The start of the week of the specified date .