nextjs-handler-no-middleware.ts

import type { NextApiRequest, NextApiResponse } from 'next';

type User = { userId: string };

const allowedMethods = ['GET'];

const formSchema = z
  .object({
    email: z.string().email(),
    password: z.string().min(4),
    passwordConfirm: z.string().min(4),
  })
  .refine((data) => data.password === data.passwordConfirm, {
    message: "Passwords don't match",
  });

const handler = (req: NextApiRequest, res: NextApiResponse<User>) => {
  try {
    if (!allowedMethods.includes(req.method!) || req.method == 'OPTIONS') {
      return res.status(405).send({ message: 'Method not allowed.' });
    }

    // Validate the incoming data and return 400 if it's not what is expected
    const body = typeof req.body === 'object' ? req.body : JSON.parse(req.body);
    const validation = formSchema.safeParse(body);

    if (!validation.success) {
      return res.status(400).send({
        message: validation.error,
      });
    }

    return res.status(200).json({ userId: 'abc123' });
  } catch (error) {
    console.error(error);
    Sentry.captureException(error);
    res.status(500).send({ message: 'Server error!' });
  }
};

export default handler;