Next.js: Next.js useRouter() query: { amp: undefined }

[tsoisauce]

I am having issues passing in query objects to useRouter() hook. I am attempting to capture URL params and pass it into a page component pages/post.js server-side using koa. and koa-router.

I am using Koa.js as my middleware based on next.js example: custom-koa-server
and using Next's documentation: Custom routes (using props from URL)

// server.js

app.prepare().then(() => {
  const server = new Koa();
  const router = new Router();

  router.get("/post/:slug", async ctx => {
    await app.render(ctx.req, ctx.res, "/post", { slug: ctx.params.slug });
    ctx.respond = false;
  });

  router.get("*", async ctx => {
    await handle(ctx.req, ctx.res);
    ctx.respond = false;
  });

  server.use(async (ctx, next) => {
    ctx.res.statusCode = 200;
    await next();
  });

  server.use(router.routes());
  server.listen(port, () => {
    console.log(`> Ready on http://localhost:${port}`);
  });
});

// pages/post.js

import { useRouter } from "next/router";

const Post = () => {
  const router = useRouter();
  console.log(useRouter());
  const { slug } = router.query;

  return <p>My Blog Post: {slug}</p>;
};

export default Post;

useRoute() console.log

// output: console.log(useRoute());

ServerRouter {
  route: '/post',
  pathname: '/post',
  query: { amp: undefined },
  asPath: '/post/testing' }

When attempting to access the query object, no matter what, I get { amp: undefined }

Any help on this will be super helpful! Thank you in advance!

[Timer]

Hi! Questions belong on our Spectrum, please open a support request there with a reproduction repository.

Also, in your provided code I don't see the need for a custom server, dynamic routes would fulfill your needs:
https://nextjs.org/docs#dynamic-routes

[tsoisauce]

@Timer Thanks! Apologies for the misplacement...issue posted here

oh and the reason why I am not using Dynamic Routes is that this will eventually be a server-side fetch to an API and passed rendered into a page component. Details in the General Channel of Next.js Spectrum.

[Timer]

Does getInitialProps not support what you're trying to do?

[jingyuanhe]

i have the same problem，How did you solve it

[chanced]

@jingyuanhe

All you need to do to resolve this is useEffect to make sure it runs after router has initialized.

For example:

  const [queryId, setQueryId] = useState(null)
  useEffect(()=> {
    if(router && router.query) {
      setQueryId(router.query.id)
    }
  }, [router])

[bduffany]

It seems a bit user-unfriendly that the router.query is not properly initialized until first render. What's the technical reasoning behind this?

[denvaar]

This is the workaround I used:

const queryString = require('query-string'); // https://www.npmjs.com/package/query-string
const { filters } = queryString.parse(router.asPath.substring(1));

I noticed that router.query was missing the query params as my component was re-rendered, but they were correct on router.asPath. I parse the params manually from that instead.

[codefist]

It seems a bit user-unfriendly that the router.query is not properly initialized until first render. What's the technical reasoning behind this?

There can't be a good reason, it's a bug. The returning of the router object SHOULD block by default, or we should be able to configure it to block until the query attribute has been set.