Uncaught TypeError: callback is not a function FullCalendar

Question

i have a problem when i'm trying to put the events on the calendar, an error show:

document.addEventListener("DOMContentLoaded", function () {
  var calendarEl = document.getElementById("calendar");
  var calendar = new FullCalendar.Calendar(calendarEl, {
    initialView: "dayGridMonth",
    events: function (start, end, timezone, callback) {
      jQuery.ajax({
        url: "/getAllCitas",
        type: "GET",
        success: function (doc) {
          var events = [];
          doc.forEach(function (evt) {
            events.push({
              title: evt.paciente,
              start: evt.date,
              end: evt.date,
            });
          });
          console.log(events);
          callback(events);
        },
      });
    },
  });
  calendar.render();
});

Error

Uncaught TypeError: callback is not a function
    at Object.success (citas.js:179)
    at c (jquery.min.js:2)
    at Object.fireWith [as resolveWith] (jquery.min.js:2)
    at l (jquery.min.js:2)
    at XMLHttpRequest.<anonymous> (jquery.min.js:2)

event result. The doc is a json that have more infomation i only need the information like it is in the event.

0: {title: undefined, start: "2021-03-18", end: "2021-03-18"}
1: {title: undefined, start: "2021-04-02", end: "2021-04-02"}
2: {title: undefined, start: "2021-04-02", end: "2021-04-02"}
3: {title: undefined, start: "2021-04-06", end: "2021-04-06"}
4: {title: undefined, start: "2021-04-05", end: "2021-04-05"}
5: {title: "603fd0e423f0d241ecfdd337", start: "2021-04-06", end: "2021-04-06"}
6: {title: "Carlos", start: "2021-04-08", end: "2021-04-08"}

I need your help, thanks

Answer 1

I got the solution, the callback like you said was from an old version. Now its successCallback, i change it and now it works, this is the new code

document.addEventListener("DOMContentLoaded", function () {
  var calendarEl = document.getElementById("calendar");
  var calendar = new FullCalendar.Calendar(calendarEl, {
    initialView: "dayGridMonth",
    events: function (fetchInfo, successCallback, failureCallback) {
      jQuery.ajax({
        url: "/getAllCitas",
        type: "GET",
        success: function (res) {
          var events = [];
          res.forEach(function (evt) {
            events.push({
              title: evt.paciente,
              start: evt.date,
              end: evt.date,
            });
          });
          successCallback(events);
        },
      });
    },
  });
  calendar.render();
});

Thanks