Add custom class on x-number of days (months/years) on jQuery UI datepicker dates (each td)

Question

I am trying to dynamically add a class to a number of "td" within the jQuery UI datepicker based on the values from "periodValue" and "periodType".

I am having serious trouble in implementing a method of adding the class "your-custom-class" to the x-number of days directly after the current day.

For instance, if today is 29/12/2023 [29] then in my coded example, the next 5 days should have the class "your-custom-class". So this would be: 30/12/2023, 31/12/2023, 01/01/2024, 02/01/2024 and 03/01/2024.

$(document).ready(function() {

  let periodValue = 5;
  let periodType = d;



  $('.input .date').each(function() {
    $(this).on('click', function() {
      let inputContainer = $(this).closest('.input');
      if (inputContainer.hasClass('kn-custom-calendar-confirmation-period')) {
        addCustomClassToDates(periodValue, periodType);
      } else {
        removeCustomClassToDates();
      }
    });
  });

  // Initialize datepickers with change event
  $('.input .date').each(function() {
    var inputId = $(this).attr('id');
    var $input = $('#' + inputId);

    $input.datepicker({
      // Other datepicker options...
      onChangeMonthYear: function(year, month, inst) {
        updateCustomClasses();
      }
    }).on('change', updateCustomClasses);
  });
});

function updateCustomClasses() {
  let inputContainer = $('.input.kn-custom-calendar-confirmation-period');
  if (inputContainer.length > 0) {
    let periodValue = parseInt(inputContainer.data('periodValue'), 10);
    let periodType = inputContainer.data('periodType');
    addCustomClassToDates(periodValue, periodType);
  } else {
    removeCustomClassToDates();
  }
}

function addCustomClassToDates(periodValue, periodType) {
  var currentDate = new Date(); // Get today's date
  var endDate = calculateEndDate(currentDate, periodValue, periodType); // Calculate end date

  $("#ui-datepicker-div .ui-datepicker-calendar tbody td").each(function() {
    var tdDate = $(this).data('year') + '-' + ($(this).data('month') + 1) + '-' + $(this).text().trim();
    tdDate = new Date(tdDate);

    if (tdDate > currentDate && tdDate <= endDate) {
      $(this).addClass('your-custom-class');
    }
  });
}


function calculateEndDate(startDate, periodValue, periodType) {
  var endDate = new Date(startDate);

  switch (periodType) {
    case 'd':
      endDate.setDate(endDate.getDate() + periodValue);
      break;
    case 'm':
      endDate.setMonth(endDate.getMonth() + periodValue);
      break;
    case 'y':
      endDate.setFullYear(endDate.getFullYear() + periodValue);
      break;
  }

  return endDate;
}


function removeCustomClassToDates() {
  $("#ui-datepicker-div .ui-datepicker-calendar tbody td").removeClass('your-custom-class');
}

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