feat(nuxt): add watch option and refactor dev server restarting

[danielroe]

🔗 Linked issue

❓ 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)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This provides a number of improvements to the dev server restarting behaviour:

1. it allows configuring the files that cause a server restart (with either string/RegExp - more complex patterns can be handled with builder:watch hook
2. it fixes implementation detail where we were only listening in dev server to rootDir changes, but we were trying to match against srcDir - this would have worked unless there was a custom srcDir (an undetected bug?)
3. it now offers more precise matching in pages module to detect changes and trigger restart
4. we now support restarting on actual component/composables/utils directories that are used rather than hard-coded values

What's more, because we're moving the logic into the ad-hoc modules that actually care about this, it should mean we integrate better with upcoming nuxi-ng, but definitely cc: @pi0 in case you foresee any issues here.

📝 Checklist

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

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[Atinux]

Looks much better now and also bringing back a needed feature from Nuxt 2 to Nuxt 3 (ie: Tailwind module for instance)

[mcfarljw]

This feature hasn't been added to the documentation yet.

[KnifeFed]

How do you use this? I tried all imaginable combinations of watch: ['tailwind.config.ts'] but it's not restarting the server when changing the file.

[danielroe]

@KnifeFed Those paths need to be absolute. I've merged a fix to allow you to use paths relative to your srcDir, which will be included in the next patch release.

[FreekVR]

Is the fix for relative paths confirmed to be merged?

I've tried every variation, but the watcher only works with abspath for me on nuxt 3.6.0

    watch: [
        '/assets/styles/css-variables.js'
    ],
    watch: [
        './assets/styles/css-variables.js'
    ],
    watch: [
        'assets/styles/css-variables.js'
    ],
    watch: [
        '@/assets/styles/css-variables.js'
    ],

[danielroe]

@FreekVR Yes, this was merged. If you are experiencing a regression, please do open a new issue with a reproduction.

[plcdnl]

I'm so sorry but i'm trying to do it with nuxt 3.6.5 and it doesn't restart the app. Both with the absolute url and with the relative one

[danielroe]

Let's track in #22272.