Known issue: HMR not working on http://localhost:3000 for Next.js

[Vadorequest]

Next.js comes with HMR, which is great. But it doesn't work on http://localhost:3000 yet.
It works on http://localhost:3001 though

But it would be a better developer experience to have everything working seamlessly on http://localhost:3000

• I tried to simply use nextProxy(req, res) but got TypeError: Cannot read property 'waitUntilReloaded' of undefined at HotReloader._callee7$ (/Users/vadorequest/dev/serverless-with-next/node_modules/next/dist/server/hot-reloader.js:658:44)
• Then, I decided to proxy requests that Express doesn't want to handle to 3001, so that Next.js app handles them. But the proxy messes up with HMR and I haven't been able to fix it:
  • I tried to proxy all /_next by doing app.use('/_next/', proxy('http://localhost:3001/_next/')); but then I get 404 for all js scripts like http://localhost:3000/_next/-/main.js
  • I tried to proxy them all one by one but then they return HTML content instead of JS (basically the index page), ex: app.use('/_next/-/main.js', proxy('http://localhost:3001/_next/-/main.js'));
  • If you manually browse to http://localhost:3001/_next/-/main.js it works okay and return the actual JS file
  • I tried to disable HMR by setting dev: false but then the Next.js app complains Could not find a valid build in the '.next' directory!
  • I tried to force contentType to text/event-stream when proxying /_next/webpack-hmr and it seem to work okay as long as Express doesn't catch the request first
    (which is the case with GET /:level1/:level2 route), and it does display [HMR] connected but nothing happens when a file is changed.

[Vadorequest]

Opened issue at Next.js: vercel/next.js#3984

[Vadorequest]

The waitUntilReloaded was caused because of the missing nextApp.prepare() call. But when using it, the application become quite unstable, with infinite webpack rebuild, and therefore very slow.

I had noticed the same behaviour on other apps using serverless-offline and nextApp.prepare().

nextApp.prepare() is supposed to be done only once, but because we export our app instead of creating a server, we actually run nextApp.prepare() at every call.

[cbrulak]

was this ever resolved? I'm seeing this error after forking the tutorial.

[Vadorequest]

@cbrulak I strongly suggest not using this boilerplate anymore it's completely outdated.

Take a look at http://github.com/UnlyEd/next-right-now which is up-to-date and much better in every aspect. (more complicated, though)