cssbundling-rails VS propshaft

See the issue I opened on Github. [EDIT: closed by DHH recently]

In the Procfile.dev that's currently generated by the cssbundling-rails and jsbundling-rails gems, we can see that they write the web process like:

The functionality comes from https://github.com/rails/jsbundling-rails and https://github.com/rails/cssbundling-rails -- both come with Rails 7 and all you have to do is generate your app with the choices you want such as -j esbuild --css tailwind.

TailwindCSS from CSS Bundling for Rails - (this post)

Maybe https://github.com/rails/cssbundling-rails does what you want? For CSS only, afaik it's perfectly fine to mix different approaches for CSS and JS within one Rails app, so you could still use importmaps for JS.

The docs at https://github.com/rails/cssbundling-rails clearly state that

Install cssbundling-rails gem.

Propshaft has a smaller scope than sprockets and requires you to rely on the js-bundling and css-bundling gems to handle the building of CSS and JS assets. Read the docs for an extensive upgrade guide.

As you may know there's also a [CSS bundling](https://github.com/rails/cssbundling-rails). However, I've only upgraded a trivial project, don't know how involved that would be.

Ruby On Rails, thanks to propshaft, closes a chapter. Welcome to 2023, where deploying JavaScript and CSS is a breeze. Welcome to the no-build era.

No mention of propshaft which is the true replacement for sprockets: https://github.com/rails/propshaft

Learning about new ways to manipulate data in Ruby is always fun. This article details a way to access hash values as if they were methods via the ActiveSupport::OrderedOptions class. Initially, it wasn't clear why someone would reach for this over the default syntax, but the author pointed out that syntax can be helpful in keeping configuration files clean and readable. Apparently, this can be observed in the wild in the Propshaft (an asset pipeline library) codebase, which uses it to define config.assets in Railtie.

Propshaft is an asset pipeline library for Rails. It uses OrderedOptions to define the config.assets settings, instead of creating a new configuration object. You can read the complete source on Github.

Propshaft has a smaller scope than sprockets and requires you to rely on the js-bundling and css-bundling gems to handle the building of CSS and JS assets. Read the docs for an extensive upgrade guide.

[They have a replacement in the works for sprockets](https://github.com/rails/propshaft), but I'm ignoring it for now. Just coping with js-bundling and css budling is enough for me.

What an exciting couple of months it has been for the Rails community! Rails 7 was released in December of 2021 and this month we are welcoming Propshaft. David Heinemeier Hansson (DHH), the creator of Rails, released a post on Feb. 11 introducing the community to the new and improved asset pipeline for Rails. While Propshaft likely won't be the default until at least Rails 8, it promises a simpler solution to asset management over its predecessor, Sprockets. Sprockets, the current default asset pipeline library, has grown increasingly heavy over the years as it has attempted to shoulder all things related to bundling, minifying, transpiling, and compressing. Enabled by the new era of tech that makes Rails 7 possible, Propshaft is touted as being "absolutely tiny" in comparison and aims to provide the following: a configurable load path for your assets, digest stamping for long-expiry cache and better performance, a development server that removes the need to pre-compile assets, and basic compilers instead of full transpilers. Sprockets will require relatively long-term support and will remain the default for now but fret not! You can create a Rails 7+ app using Propshaft, or upgrade an existing app and start using it now.

There’s more info on the GitHub repository, stating

Oh and there's a new option https://github.com/rails/propshaft which will replace sprockets in the future, didn't use it though, but looks promising