TypeError: Cannot read property 'isNextDevCommand' of undefined

[j-quelly]

Bug report

Describe the bug

TypeError: Cannot read property 'isNextDevCommand' of undefined options in createServer() do not seem to have the isNextDevCommand property

To Reproduce

1. start custom server
2. navigate to /
3. See error

Expected behavior

Not this

Screenshots

System information

• OS: macOS
• Browser (if applies) chrome
• Version of Next.js: 9.3.2
• Version of Node.js: v12.16.2

Additional context

[Timer]

Sounds like the next instance is being instantiated incorrectly.

Look for:

const app = next()

And be sure you're passing dev as shown in our examples:

const app = next({ dev: boolean })

---

Relevant examples:

next.js/examples/custom-server-express/server.js

Line 6 in 6ca00bf

const app = next({ dev })

next.js/examples/custom-server/server.js

Line 6 in 6ca00bf

const app = next({ dev })

next.js/examples/custom-server-typescript/server/index.ts

Line 7 in 6ca00bf

const app = next({ dev })

Happy to take a PR giving a better error message when there's bad user input.

[j-quelly]

Hey thanks Timer, my server is as follows:

Do you see anything that looks wrong here?

const cacheableResponse = require('cacheable-response');
const express = require('express');
const next = require('next');
const cookieParser = require('cookie-parser');
const { uuid } = require('uuidv4');

const port = 8001;
const dev = process.env.NODE_ENV !== 'production';
const app = next({ dev });
const handle = app.getRequestHandler();

const ssrCache = cacheableResponse({
  ttl: 1000 * 60 * 60, // 1hour
  get: async ({ req, res, pagePath, queryParams }) => {
    const data = await app.renderToHTML(req, res, pagePath, queryParams);

    // Add here custom logic for when you do not want to cache the page, for
    // example when the page returns a 404 status code:
    if (res.statusCode === 404) {
      res.end(data);
      return;
    }

    return { data };
  },
  send: ({ data, res }) => res.send(data),
});

const SSRController = ({ pagePath }, req, res) => {
  const {
    context: { isProduction },
  } = req;

  if (isProduction) {
    return ssrCache({ req, res, pagePath });
  }

  return app.render(req, res, pagePath, req.query);
};

app.prepare().then(() => {
  const server = express();
  server.use(cookieParser());

  server.get('/', SSRController.bind(null, { pagePath: '/' }));

  // handle all other requests
  // in dev mode this will always recompile
  // in production this will either return a precompiled page via renderToHTML
  // or will compile the requested route if it invokes methods that require a server
  // the SSR pages that resolve here are not cached
  // more here: https://gist.github.com/timruffles/153a04f6956399907d90d73af0093e9f
  server.get('*', (req, res) => handle(req, res));

  // error handler for express
  // this does not catch errors thrown in next.js
  server.use((err, req, res, next) => {
    const {
      context: { isDevelopment },
    } = req;

    if (err) {
      const scope = {
        sid: req.cookies.sid,
        method: req.method,
        url: req.path,
        query: req.query,
        headers: req.headers,
        params: req.params,
        msg: err.message,
        timestamp: new Date(),
        err,
      };
      if (!isDevelopment) {
        plogger.error(err.message || 'error', scope);
      } else {
        console.error(err.message || 'error', scope);
      }
    }

    next();
  });

  server.listen(port, err => {
    if (err) throw err;
  });
});

[Timer]

Without a full demo I can't help trace this down!

[todortotev]

Happy to take a PR giving a better error message when there's bad user input.

If I understand correctly, you want a better error message when the user passes any variable that isn't a boolean, correct?

Cause right now I can pass an integer, string, array, or even an arrow function and I won't see any warnings at all.

[j-quelly]

@todortotev I'm not asking for better error message.

I'm receiving this error message and I cannot figure out why.

@Timer You want to see a demo of the server failing to start and throwing the error message I attached as a screenshot? Happy to attach a gif, but I don't see what value that adds?

[moh12594]

@Timer I opened this PR to have a better message error, it seems like the error happens when the parameter isn't defined.

[j-quelly]

What just happened? Did any of you read this thread?

[timneutkens]

@Timer You want to see a demo of the server failing to start and throwing the error message I attached as a screenshot? Happy to attach a gif, but I don't see what value that adds?

A full github repository would help

[balazsorban44]

This issue has been automatically closed after 30 days of inactivity with no reproduction. If you are running into a similar issue, please open a new issue with a reproduction. Thank you.

[github-actions]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.