index.js

const { createNodeMiddleware, createProbot } = require("probot");

const app = require("../");
const probot = createProbot();
const middleware = createNodeMiddleware(app, {
  probot,
  webhooksPath: "/",
});

/**
 * Redirect `GET /` to `/stats`, pass `POST /` to Probot's middleware
 *
 * @param {import('@vercel/node').VercelRequest} request
 * @param {import('@vercel/node').VercelResponse} response
 */
module.exports = (request, response) => {
  if (request.method !== "POST") {
    response.writeHead(302, {
      Location: "/stats",
    });
    response.end();
    return;
  }

  middleware(request, response);
};