如何从flatpicker获取起始日期和终止日期？

<input type="text" id="date-picker" />

// 获取起始日期和终止日期的方法
function getStartDate() {
    return document.getElementById("start-date").value;
}

function getEndDate() {
    return document.getElementById("end-date").value;
}

// 初始化日期选择器
const datePicker = flatpickr("#date-picker", {
    onChange: function(selectedDates, dateStr, instance) {
        const startDate = getStartDate();
        const endDate = getEndDate();
        console.log("起始日期：" + startDate);
        console.log("终止日期：" + endDate);
    }
});

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/flatpickr/dist/flatpickr.min.css">
<script src="https://cdn.jsdelivr.net/npm/flatpickr"></script>