DartSass

Mix tasks for installing and invoking sass.

Installation

If you are going to build assets in production, then you add dart_sass as a dependency on all environments but only start it in dev:

def deps do
  [
    {:dart_sass, "~> 0.1", runtime: Mix.env() == :dev}
  ]
end

However, if your assets are precompiled during development, then it only needs to be a dev dependency:

def deps do
  [
    {:dart_sass, "~> 0.1", only: :dev}
  ]
end

Once installed, change your config/config.exs to pick your dart_sass version of choice:

config :dart_sass, version: "1.36.0"

Now you can install sass by running:

$ mix sass.install

And invoke sass with:

$ mix sass default assets/css/app.scss priv/static/assets/app.css

If you need additional load paths you may specify them:

$ mix sass default assets/css/app.scss --load-path=assets/node_modules/bulma priv/static/assets/app.css

The executable may be kept at _build/sass. However in most cases running dart-sass requires two files: the portable Dart VM is kept at _build/dart and the Sass snapshot is kept at _build/sass.snapshot.

Profiles

The first argument to dart_sass is the execution profile. You can define multiple execution profiles with the current directory, the OS environment, and default arguments to the dart_sass task:

config :dart_sass,
  version: "1.36.0",
  default: [
    args: ~w(css/app.scss ../priv/static/assets/app.css),
    cd: Path.expand("../assets", __DIR__)
  ]

When mix sass default is invoked, the task arguments will be appended to the ones configured above.

Acknowledgements

This package is based on the excellent esbuild by Wojtek Mach and José Valim.

License

Copyright (c) 2021 CargoSense, Inc.

dart_sass source code is licensed under the MIT License.