Add note about standalone mode not working for app router

[bjornarhagen]

No description provided.

[HamAndRock]

We are using standalone mode with appDirectory without any issues on 2 prod projects, as far as I know. The only issue we have is the server dying after some time due to OOM issues, but that's I think unrelated to standalone: #45508

But please correct me if I am wrong and we should get rid of output: standalone

[Innei]

It seems that this isn't just a problem with appDir, my project uses pageDir, but it's also has this problem

[HamAndRock]

Yeah, I know. Just wanted to say that we use standalone mode without any problems with appDirectory. The OOM/crashes are not related to this issue.

[bjornarhagen]

Sorry if this is actually no longer the case, and standalone mode should work fine with the App router. I just ran into this when trying to use standalone mode for this template https://github.com/medusajs/nextjs-starter-medusa. I also tried to install next@canary and build, but get the same error.

So without standalone mode it works fine, but when I turn it on, I get this build error

> Build error occurred
[Error: ENOENT: no such file or directory, lstat '/Users/USERNAME/dev/nextjs-starter-medusa/.next/server/app'] {
  errno: -2,
  code: 'ENOENT',
  syscall: 'lstat',
  path: '/Users/USERNAME/dev/nextjs-starter-medusa/.next/server/app'
}

[HamAndRock]

Well I am just unsure, you get some weird errors on start but seems like it works fine in prod,

[leerob]

Blocking because I'd like to get some clarity here first before this gets merged.

[DuCanhGH]

@bjornarhagen if you are using the pages/ directory only, perhaps you can try setting experimental.appDir to false? Or add an app/ page if there's none? Thanks!

I added App Router support for output: "standalone" months ago, so the note added in this PR is not correct :)

[bjornarhagen]

@DuCanhGH I see, must be something https://github.com/medusajs/nextjs-starter-medusa is doing that is causing the standalone build to fail then. Setting experimental.appDir to false does fix the issue.

Thank you so much! 😄

[leerob]

Note that the experimental flag is not needed with v13.4+.