JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/flatpickr/dist/flatpickr.min.css">
<script src="https://cdn.jsdelivr.net/npm/flatpick"></script>
<!-- Input for date picker -->
<input type="text" id="datepicker" placeholder="Select Date">
<button id="disableButton">Disable Dates</button>

<!-- Include Flatpickr CSS -->
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/flatpickr/dist/flatpickr.min.css">

<!-- Include Flatpickr JavaScript -->
<script src="https://cdn.jsdelivr.net/npm/flatpickr"></script>

<script>
  document.addEventListener('DOMContentLoaded', function() {
    // Initialize the Flatpickr instance and store it in a variable
    const picker = flatpickr("#datepicker", {
      enableTime: false,
      dateFormat: "Y-m-d",
      enable: ["2024-10-26"]
    });

    document.getElementById('disableButton').addEventListener('click', function() {
      picker.set('_enable', undefined);
    });
  });
</script>