code: function isDayInRange(day, range) {
    var from = range.from,
        to = range.to;
  
    return from && isSameDay(day, from) || to && isSameDay(day, to) || from && to && isDayBetween(day, from, to);
  }
docs: Return `true` if a day is included in a range of days.
  
  @export
  @param  {Date}  day
  @param  {Object}  range
  @return {Boolean}