deraen / sass4clj

SASS compiler for Clj, Lein and Boot, using Libsass Java wrapper

Sass4clj

Clojure wrapper for jsass JNA wrapper for Libsass. This repository also contains Boot and Leiningen tasks.

For parallel Less library check less4clj

ATTENTION: libsass (the C library) and the JNA wrapper library jsass are deprecated. Consider using Dart Sass if you do not need to read SCSS files from the Java classpath. You can integrate Dart Sass process with Shadow CLJS.

Both sass4clj still works and will receive bug fixes, but the difference between libsass and dart-sass will continue growing.

Some ideas if you need to read files from the classpath or jar files:

• It might be possible to extend dart-sass through Importer API
• Extract files from the jar files in a script before calling dart-sass compile (for example, using clj and unzip)

Features

• Jsass features
  • Requires Java 1.8
  • Linux & Windows builds are automatically tested
  • (Doesn't work on Alpine based Docker images)
• Load imports directly from Java classpath (e.g. Webjars)
  • Add dependency [org.webjars.bower/bootstrap "4.0.0-alpha"] to use Bootstrap
• Assumes that files starting with _ are partial files and should not be compiled into CSS files.
• Non feature: compilation warnings are reported by libsass/jsass directly to stdout, and aren't accessible from sass4clj API.

Boot

• Provides the sass task (deraen.boot-sass/sass)
• Select main files using inputs option
• or, for each .sass or .scss file not starting with _ in the fileset creates equivalent .css file.
• Check boot sass --help for task options.

Leiningen

• Provides the sass4clj task
• Select main files using inputs option
• or, for each .sass or .scss file not starting with _ in source-dirs creates equivalent .css file.
• Check lein help sass4clj for options.

Clj

Test in the repository:

clj -m sass4clj.main --source-paths test-resources

Check clj -m sass4clj.main --help for options.

Import load order

Loading order for @import "{name}"; on file at {path}

1. Local file at {path}/{name}.sass or {path}/{name}.scss
2. Local files on other source-paths, {source-path}/{name}.ext
3. Classpath resource (io/resource "{name}.ext")
4. Classpath resource (io/resource "{path}/{name}.ext")
5. Webjar asset
   • Resource META-INF/resources/webjars/{package}/{version}/{path} can be referred using {package}/{path}
   • For example @import "bootstrap/scss/bootstrap.scss"; will import META-INF/resources/webjars/bootstrap/4.0.0-alpha/scss/bootstrap.scss

FAQ

Shadow-cljs integration

If you want to combine CLJS compilation with Shadow CLJS and Sass compilation, you can create your function which starts both watches and run this using shadow-cljs clj-run task.

(ns app.shadow
  (:require [shadow.cljs.devtools.api :as shadow]
            [sass4clj.api :as sass]
            [clojure.edn :as edn]))

(defn watch
  {:shadow/requires-server true}
  [& _args]
  ;; Sass compilation probably starts faster.
  ;; Both watches keep running until ctrl-c.
  (sass/start (-> (edn/read-string (slurp "sass4clj.edn"))
                  (assoc :target-path "target/dev/public/css")))
  (shadow/watch :app))

The configuration file, sass4clj.edn, is also supported by sass4clj.main namespace. You could use that to compile CSS for your production build instead of the leiningen plugin.

And start the watch with (or with whatever tool you are using):

lein run -m shadow.cljs.devtools.cli clj-run app.shadow/watch

You need to ensure that the classpath used by shadow-cljs contains deraen/sass4clj and any packages where you are importing sass files from.

Log configuration

If you don't have any slf4j implementations, you will see a warning:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

To disable this, add a no operation logger to your project. As this is only required on the build phase, you can use :scope "test" so that the dependency is not transitive and is not included in Uberjar. Alternatively, you can add this dependency to your Leiningen dev profile.

[org.slf4j/slf4j-nop "1.7.13" :scope "test"]

License

Copyright © 2014-2021 Juho Teperi

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.