NextJS https server

server.js

// @ts-check
// server.js
const { createServer } = require("https");
const fs = require("fs").promises;
const { parse } = require("url");
const next = require("next").default;

const hostname = "localhost";
const port = 3000;
const app = next({ dev: true, hostname, port });
const handle = app.getRequestHandler();

app.prepare().then(async () => {
  // reading env after `Next.prepare()` call
  // https://github.com/vercel/next.js/issues/12269#issuecomment-933322120
  const HTTPS_KEY_PATH = process.env.HTTPS_KEY_PATH;
  const HTTPS_CERT_PATH = process.env.HTTPS_CERT_PATH;
  const key = await fs.readFile(HTTPS_KEY_PATH, { encoding: "utf-8" });
  const cert = await fs.readFile(HTTPS_CERT_PATH, { encoding: "utf-8" });

  const server = createSecureServer({ key, cert }, async (req, res) => {
    // Be sure to pass `true` as the second argument to `url.parse`.
    // This tells it to parse the query portion of the URL.
    const parsedUrl = parse(req.url, true);
    await handle(req, res, parsedUrl);
  });

  server.listen(port, (err) => {
    if (err) throw err;
    console.log(`> Ready on https://${hostname}:${port}`);
  });
});

server.md

Run the dev server

node server.js

HTTPS_KEY_PATH and HTTPS_CERT_PATH are custom environment variables.
It is important to access process.env only after app.prepare() call, so it would do the nextjs thing with environment variables first.