Hi!

Working hard to see where AssetMapper adjustments need to be made. 3 changes proposed here:

1. AssetMapper's "public output path" awareness was moved to a newPublicAssetsPathResolver service
2. The asset compilers were updated to use relative paths when adjusting paths in files.
3. Drop the "mime type" stuff entirely - except for the "dev server" so it can set the content-type. Asset compiler's can use$mappedAsset->getPublicExtension() instead.

Why these changes?

1. Allow public/assets/ structure to flatten/change

The newPublicAssetsPathResolver + the "adjustment" of import/url paths in the compilers allows the "output" directory structure to be decoupled from the source structure. Currently the output structure matches your "source" structure, so you get things likepublic/assets/styles/app.css orpublic/assets/bundles/easyadmin/foo.css. We could add an option in the future (or the user could decoratePublicAssetsPathResolver immediately) to "flatten" everything into justpublic/assets/.

2. Allow for building of certain files, like.scss or.jsx

These changes allow users to create... more controversial functionality that could build certain files automatically. For example, you could have:

<linkrel="stylesheet"href="{{ asset('styles/app.scss') }}">

Locally, I have a custom compiler that executes thedart-sass binary to convert this to CSS. Then, by decoratingPublicAssetsPathResolver, I'm changing the public path forstyles/app.scss so that it ends with.css. This is about 50 lines of code that results in the sass-compiled CSS file being properly rendered onto the page.

I have a similar compiler + path decorator locally that compiles.jsx =>.js using the babel binary. Usage:

// assets/app.jsimportHelloWorldComponentfrom'./HelloReact.jsx';// ... render like normal

I realize usage like this is more controversial... however it's also super pragmatic if you DO use Sass or have some React components. The alternative would be to run thesass binary manually, import the built.css file and probably ignore that file fromgit.

Thanks for your consideration :).

Cheers!