Returns a new CalculationDate relative to the CalculationDate on the same day of the week for the week following the one that contains the CalculationDate.
var date = now.valueOf('2017-03-15'); // a Wednesday
var nextWeek = date.nextWeek();
console.log('nextWeek = %s', nextWeek);
//nextWeek = 2017-02-22 00:00:00