Your change handler function has access to two arguments: dateStr and selectedDates.

The first, dateStr, is a string of the chosen date. The second, selectedDates, is an array of selected date objects. In many use cases selectedDates will have only one value but you’ll still need to access it from index 0.

NOTE: On Change does not account for manual input by users, so if your date picker sets allowInput, you should use the onClose method instead.