RFC - App-wide shared static/stale data

[Vadorequest]

I've implemented #334 today

It has a few benefits, especially around build optimizations, and also only generates the necessary pages (for actives languages) instead of generating all pages for all languages no matter what.

It also has a few considerations, I've found the plugin to make the app much less resilient to changes, and provide quite a bad dev experience on some troubling code issues, see ricokahler/next-plugin-preval#26

Overall, I like the changes, but I'm concerned about maintainability. It's an optimization I've wanted to do for more than a year, I hope the next-plugin-preval improves and fixes those developer-facing issues.

Don't hesitate to share your thoughts!

[Vadorequest]

Similar optimization has been implemented for i18n (Locize) too: #337

[samuelcastro]

This is really interesting. I wasn't aware about this plugin.

[Vadorequest]

I've encountered more issues, especially with larger datasets (our own private app):

• Is it possible to configure this plugin to only run once when the server starts? ricokahler/next-plugin-preval#27
• Another issue due to circular references, build on Vercel fails (the NRN demo doesn't have circular data, that's why it wasn't affected) My own mistake trying to JSON.stringify circular data

I'll disable the plugin during development, it's a shame but I don't see a better alternative until it's fixed.

[Vadorequest]

PR at #341