What's the best place to add code that is only meant to be executed once when doing a static build and has no relationship with any route?

[adriancuadrado]

Summary

If the code does not have any relationship with any route it shouldn't go in any layout or page, but because it is a static build, instrumentation.ts won't be run.

Is this a bug though? Should instrumentation.ts be run when doing a static build? I couldn't find any info about it. (If this is a bug please let me know so I can create an issue for it).

Anyways, I don't want to add the code to any generateStaticParams() because I am not generating any static parameter so it doesn't seem appropriate to add my code there.

I don't want to add the code to any server component because it doesn't affect the output of that component.

Specifically, I have a folder with some markdown files and I want to create an RSS feed. I want to create the xml file and put it in the public/ folder using this JS library.

The best I can think of right now is to create a separate javascript file to do just that and modify my npm build command to run it before next build, but I wanted to ask just in case someone else comes up with a more appropriate solution.

Please keep in mind that I worded the title of this discussion in such a way to allow for more generic answers that could apply in cases other than mine. Just in case a solution comes up but it only makes sense in the context of RSS feed generation. This way more people might benefit from this.

Additional information

No response

Example

No response

[icyJoseph]

It sounds like, for your use case, you could use, next.config.js as a function, and check for the build phase:

• https://nextjs.org/docs/app/api-reference/config/next-config-js#phase

• next.js/packages/next/shared/lib/constants.ts

  Line 20 in 5e6b008

  export const PHASE_PRODUCTION_BUILD = 'phase-production-build'

Though, since your use case, is totally independent from the rest of your app, running a separate script, sounds just about right too.

[adriancuadrado]

I just wanted to create an RSS feed and realized I could return the feed in the GET method of src/app/rss.xml/route.ts instead.

If someone else wants to create a file or something like that you can try a simialr approach and do it this way.

I don't like using next.config.js because from what I've seen it gets executed more than once when building the static site. And I don't like creating and running a separate script either because I am deploying my site to github pages using a Github Action that runs next build instead of npm build. I could change that easily but I think it makes more sense to find a JS file in the project to execute my code to make sure it gets executed once even if I decided to deploy somewhere else and couldn't run npm build instead of next build for whatever reason.

[icyJoseph]

Oh that's correct! Nice approach. That yields the same result, and you can even revalidate and what not within the Route Handler.

[ivocreates]

[adriancuadrado]

Your answer is AI generated and literally doesn't add anything to what the other answers already said.

Thank you for nothing.

[ivocreates]

You're right — after reviewing my previous response, I realized it didn’t add any meaningful value beyond what had already been mentioned. That’s why I chose to delete it — not out of disregard, but to avoid cluttering the discussion with redundant information.

I also want to be transparent: I did use AI to help refine the grammar and structure of my reply, but the core of the content came from my research and understanding. My intention was only to present it more clearly, not to mislead or add noise.

Apologies if it came across otherwise, and I’ll be more mindful going forward to ensure my responses are both original and genuinely helpful.