Switch from Sass imports to Sass Module System

[inwardmovement]

Just putting this here, maybe for v5.

Sass Module System

[MartijnCuppens]

AFAICT, the module system only works in Dart Sass, not in ruby Sass or Lib Sass. Since the majority of build systems won't support this yet, I guess it won't be a good idea to switch now.

[mocsy]

What are the 'majority of build systems' you mention?
I had no problems with webpack, parcel nor gulp using the sass package.

Maybe the right approach would be to migrate from node-sass to sass first.
The module system comes as a free bonus with the migrator anyway.

That might clear these warning from my build logs as another added bonus:

WARNING: You probably don't mean to use the color value indigo in interpolation here.
It may end up represented as indigo, which will likely produce invalid CSS.
Always quote color names when using them as strings or map keys (for example, "indigo").
If you really want to use the color value here, use '"" + $color'.

  ╷
4 │     --#{$color}: #{$value};
  │         ^^^^^^
  ╵
    node_modules/bootstrap/scss/_root.scss 4:9       @import
    node_modules/bootstrap/scss/bootstrap.scss 11:9  @import

[MartijnCuppens]

@mocsy, node-sass is used more to compile sass, see https://npmcharts.com/compare/sass,node-sass?interval=30

Other than that, we have a list of other compilers using LibSass: https://sass-lang.com/libsass

Even if we switch to sass instead of node-sass (which we might do at some point), we still need to support node-sass as long as it is not deprecated.

[glen-84]

LibSass: sass/libsass#2807
Ruby Sass: EOL

[zackdotcomputer]

Just hopping in here to +1 this, especially since SASS used Bootstrap as an example for how the new package system could be used.

[jquense]

The event horizon for node-sass supporting the new module system seems like 2-3+ years, it's already many months behind libsass which seems like it's slating impl for a major release tentatively in 2021? I'd love to see Sass modules used in bootstrap, but it does seem like there needs be either a cultural shift from using libsass or an influx of new contributors to help speed up implementation. Seems like web-devs wanting to do c++ development is a fairly niche subset!

[WraithKenny]

Why not leave 4.5 as libsass compatible, and make 5 dartsass...at least until libsass updates itself (if ever). Backwards compatibility makes no sense here.

[yaquawa]

I really need this +1

[ydmitry]

Highly need this for more advanced theming support