I want to order id auto genarate and set text field, below function dosen't working. Is it correct?

function generateOrderID() {
    try {
        let lastOrderId = orderDB[orderDB.length-1].getOrderId();
        let newOrderId = parseInt(lastOrderId.substring(1,7))+1;
        if (newOrderId < 10) {
            $("#txtOrderId").val('D00-00'+newOrderId);
        }else if (newOrderId < 100) {
            $("#txtOrderId").val('D00-0'+newOrderId);
        } else {
            $("#txtOrderId").val('D00-'+newOrderId);
        }
    } catch (e) {
        $("#txtOrderId").val("D00-001");
    }
}