发送给客户端后无法设置标头

Question

我正在创建一个电子商务网站，在调用 api 下订单时出现错误。

节点：内部/进程/承诺：227 triggerUncaughtException(err, true /* fromPromise */); ^

错误 [ERR_HTTP_HEADERS_SENT]：发送到客户端后无法设置标头

    orderRouter.post(
  "/new",
  isAuth,
  expressAsyncHandler(async (req, res) => {
    if (req.body.orderItem.length === 0) {
      return res.status(404).send({ message: "Cart is empty" });
    } else {
      const order = new Order({
        orderItem: req.body.orderItem,
        shippingAddress: req.body.shippingAddress,
        paymentMethod: req.body.paymentMethod,
        user: req.body.user,
        statusId: req.body.statusId,
        isPaid: req.body.isPaid || null,
        // statusMsg = req.body.statusMsg || "No msg"
      });
      const createdOrder = await order.save();
      return res
        .status(200)
        .send({ message: "Order placed succefully", order: createdOrder });
    }
  })
);