I'm building a user auth in the backend. I created a post method for registering a new user

userRouter.post("/", expressAsyncHandler(async (req, res) =>
{
  try {
        const { name, email, password } = req.body;
        const userExists = await User.findOne({ email });
        if (userExists) {
          res.status(400).json({ message: "User already exists" });
        }
        const user = await User.create({
          name,
          email,
          password,
        });

        if (user) {
          res.status(201).json({
            data: {
              _id: user._id,
              name: user.name,
              email: user.email,
              token: generateToken(user._id),
            },
          });
        } else {
          res.status(400).json({ message: "Registration failed" });
        }
  } catch (error) {
      res.status(500).json({message:error.message})
  }
}))

It is working but shows

Cannot set headers after they send it to the client

I'm feeling a little uncomfortable with this code. so how can I make the code cleaner and more efficient? what are the best practices to follow?

Thanks in advance :)