feat(nitro)!: support overriding runtime config at a second level

[danielroe]

❓ 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

Currently we can only override at the top level of runtime config. This now allows for overriding at a second (nested) level, for example, for modules which want to allow runtime configuration. At the same time, we also normalise to upper-snake-case (baseURL -> BASE_URL)

Consider this example:

export default defineNuxtConfig({
  publicRuntimeConfig: {
    // this previously required overriding with `baseURL=other node .output/server/index.mjs`
    // but is now normalised to `BASE_URL`
    baseURL: 'test',
    // this was previously impossible to override piece-meal
    // but can now be overriden with `MY_MODULE_SOME_KEY=false node .output/server/index.mjs`
    myModule: {
      someKey: true
    }
  }
})

Notes

1. Note that we have special handling for app config - perhaps we can abandon this and default to (e.g.) APP_CDN_URL instead of NUXT_APP_CDN_URL?

   framework/packages/nitro/src/runtime/app/config.ts

   Lines 24 to 28 in a971aab

   	// Load dynamic app configuration
   	const appConfig = _runtimeConfig.public.app
   	appConfig.baseURL = process.env.NUXT_APP_BASE_URL || appConfig.baseURL
   	appConfig.cdnURL = process.env.NUXT_APP_CDN_URL || appConfig.cdnURL
   	appConfig.buildAssetsDir = process.env.NUXT_APP_BUILD_ASSETS_DIR || appConfig.buildAssetsDir

2. If we're happy with this approach, I will update the documentation.

👉 Migration

• If you are depending on overriding with a mixed-case environment variable, you should convert it to upper-snake-case instead (baseURL -> BASE_URL).

📝 Checklist

• I have updated the documentation accordingly.

[netlify]

✔️ Deploy Preview for nuxt3-docs ready!

🔨 Explore the source changes: 5a01b7a

🔍 Inspect the deploy log: https://app.netlify.com/sites/nuxt3-docs/deploys/61f7c52f7526820008515a4b

😎 Browse the preview: https://deploy-preview-3007--nuxt3-docs.netlify.app

[pi0]

(PR is merged to nitropack relesing soon)