feat(nuxt): app.config improvements

[Tahul]

🔗 Linked issue

nuxt/nuxt#14670

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Resolves:

• Use defu.arrayFn to allow overrriding arrays in multi-layer format
  • In c54292b I implemented it how it was made in @nuxt-themes/kit
  • In 1b07424 I implemented it using arrayFn as suggested in app.config improvements nuxt#14670
    • Leads to strange behaviors with HMR (array keys going null when going from a play array to function format)
  • I would say that overwriting is expected behavior in this kind of config, and that function format seem to introduce a bit of overhead for the user to understand when reading config files.
• Fixed an issue in which deep keys were not properly deleted on HMR, as seen here.
  • This portion of codes properly deepAssign on changes, but does not delete existing keys
  • Reproduction
• Implement updateAppConfig composable

Few notes about this:

I've seen appConfig merging occurs in built template here, considering that, what is the proper way to implement features that needs to have access to the fully merged app config file inside Nuxt?

In nuxt/nuxt#14670, there is mentions to:

• Use untyped to (auto)generate types from appConfig instead of defu
• Support _schema (global config) [needs new issue to track]

I would love to help on these issues but need guidance on how to resolve the whole appConfig object from Nuxt side, in order to generate typings from it.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

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[pi0]

Thanks for PR @Tahul! I think after resolving comments it is good to go 👍🏼

Please for next ones keep them small to one change.

[pi0]

I've seen appConfig merging occurs in built template here, considering that, what is the proper way to implement features that needs to have access to the fully merged app config file inside Nuxt?

If by "inside Nuxt" you mean within modules, it is not possible. App config is a runtime template and merged and available only on runtime. Modules can access or extend it via a runtime plugin.

[Tahul]

#6905 (comment)

I mean from inside Nuxt, this seem needed to generate typings and support _schema key as mentioned in the PR description.

[pi0]

I mean from inside Nuxt, this seem needed to generate typings and support _schema key as mentioned in the PR description.

We have access to nuxt.options.appConfig... But more thinking, a generic schema support for Nuxt makes more sense (it is not limited to app config feature) but can type appConfig too.

[Tahul]

I mean from inside Nuxt, this seem needed to generate typings and support _schema key as mentioned in the PR description.

We have access to nuxt.options.appConfig... But more thinking, a generic schema support for Nuxt makes more sense (it is not limited to app config feature) but can type appConfig too.

I understand we have access to nuxt.options.appConfig, but does that mean people can only write their schema from nuxt.config.ts file then?

[pi0]

I understand we have access to nuxt.options.appConfig, but does that mean people can only write their schema from nuxt.config.ts file then?

I don't expect ordinary people to use (advanced) _schema feature we are planning to add. But yes it is a built-time thing for schema not runtime. Defined either using nuxt.config or hooks.

[pi0]

Thanks