docs(layers): correct configuration requirements

[dargmuesli]

🔗 Linked issue

n/a

❓ 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

In my testing it is required to also have locales set in the project which extends another. Also, the module does not have to be redefined in a project that extends another as the module is already defined in the project which is extended.

Beyond that, It would be interesting as well to have the documentation explain why it is necessary to repeat some of the configuration in the extending project! 💡 I'm wondering why it is like that and don't know :)

📝 Checklist

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

[nuxt-studio]

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[kazupon]

Thanks! LGTM!

@BobbieGoede
Do you have anything to add?

[BobbieGoede]

Looks like that property is required, thanks for the PR!

Beyond that, It would be interesting as well to have the documentation explain why it is necessary to repeat some of the configuration in the extending project! 💡 I'm wondering why it is like that and don't know :)

Especially when using multiple layers, properties can get overwritten by each layer, so if a project is consuming a layer with lazy: true and a layer with lazy: false, depending on the order of extend the lazy property will be different. If lazy ends up being true then main the project is required to have langDir set.

Another reason for this is that files defined in locales are resolved relative to langDir, so we need a langDir in the main project to resolve locales defined in layers containing lazy loaded locales.

This behavior is a bit unintuitive and hard to explain well, ideally the main project extending i18n layers should not be required to configure anything. I'm actually working on a change to make this possible, so hopefully I can get that done soon!