当我尝试调用下面的端点时，我从postman那里得到下面的错误。

{
"success": false,
"error": "Unexpected token / in JSON at position 7"
}

• 在addFollowing函数中，您可以看到我尝试记录userId和followingId，但未从我的终端收到任何日志
• 接下来我试着用一个软件包这个软件包npm i json-sanitizer来清理req.body，但是没有用

const addFollowing = async (req, res, next) => {
  const userId = req.body.userId;
  const followId = req.body.followId;
  console.log(userId, followId);
  try {
  // Update the user's following list
  const updatedUser = await User.findByIdAndUpdate(
    userId,
    { $addToSet: { following: followId } },
    { new: true }
  ).select("username email following followers");

  if (!updatedUser) {
    return next(new ErrorResponse(404, "User not found"));
  }

  // Update the follower's followers list
  const updatedFollower = await User.findByIdAndUpdate(
    followId,
    { $addToSet: { followers: userId } },
    { new: true }
  ).select("username email following followers");

  if (!updatedFollower) {
    // Roll back the previous update to the user's following list
    await User.findByIdAndUpdate(userId, { $pull: { following: followId } });
    return next(new ErrorResponse(404, "User not found"));
  }

  // Return the updated user and follower objects
  res.json({
    user: updatedUser,
    follower: updatedFollower,
  });
  } catch (err) {
  next(err);
  }
};

我第一次在写完这个端点后调用它，它是成功的，但是后来的尝试导致了上面的错误，我一直试图把我的头包起来。因此，真的很感谢帮助。谢谢
这是我的路线

router.post("/add-following",protect, addFollowing);