index.ts

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

/**
 * Custom API implementation for rewrites to support runtime rewrite config
 * https://github.com/vercel/next.js/issues/21888
 */
export const handler = async (req: NextApiRequest, res: NextApiResponse): Promise<void> => {
  const newPath = req.url as string;
  if (newPath) {
    const url = `${process.env.SITECORE_API_HOST}${newPath}`;
    const { data, status, headers } = await axios({
      url,
      responseType: 'arraybuffer',
    });

    // map headers
    Object.entries(headers).map((h) => res.setHeader(h[0], (h[1] as string) ?? ''));

    res.status(status).send(data);
  } else {
    res.status(400).json({ error: 'Request URL was not provided.' });
  }
};

export default handler;