base on The reference implementation of Sass, written in Dart. A [Dart][dart] implementation of [Sass][sass]. **Sass makes CSS fun**. <table> <tr> <td> <img width="118px" alt="Sass logo" src="https://rawgit.com/sass/sass-site/main/source/assets/img/logos/logo.svg" /> </td> <td valign="middle"> <a href="https://www.npmjs.com/package/sass"><img width="100%" alt="npm statistics" src="https://nodei.co/npm/sass.png?downloads=true"></a> </td> <td valign="middle"> <a href="https://pub.dartlang.org/packages/sass"><img alt="Pub version" src="https://img.shields.io/pub/v/sass.svg"></a> <br> <a href="https://github.com/sass/dart-sass/actions"><img alt="GitHub actions build status" src="https://github.com/sass/dart-sass/workflows/CI/badge.svg"></a> </td> <td> <a href="https://front-end.social/@sass"><img alt="@[email protected] on Fediverse" src="https://img.shields.io/mastodon/follow/110159358073946175?domain=https%3A%2F%2Ffront-end.social"></a> <br> <a href="https://twitter.com/SassCSS"><img alt="@SassCSS on Twitter" src="https://img.shields.io/twitter/follow/SassCSS?label=%40SassCSS&style=social"></a> <br> <a href="https://stackoverflow.com/questions/tagged/sass"><img alt="stackoverflow" src="https://img.shields.io/stackexchange/stackoverflow/t/sass?label=Sass%20questions&logo=stackoverflow&style=social"></a> <br> <a href="https://gitter.im/sass/sass?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge"><img alt="Gitter" src="https://img.shields.io/gitter/room/sass/sass?label=chat&logo=gitter&style=social"></a> </td> </tr> </table> [dart]: https://www.dartlang.org [sass]: https://sass-lang.com/ * [Using Dart Sass](#using-dart-sass) * [From Chocolatey or Scoop (Windows)](#from-chocolatey-or-scoop-windows) * [From Homebrew (macOS)](#from-homebrew-macos-or-linux) * [Standalone](#standalone) * [From npm](#from-npm) * [Dart Sass in the Browser](#dart-sass-in-the-browser) * [Legacy JavaScript API](#legacy-javascript-api) * [Using Sass with Jest](#using-sass-with-jest) * [From Pub](#from-pub) * [`sass_api` Package](#sass_api-package) * [From Source](#from-source) * [In Docker](#in-docker) * [Why Dart?](#why-dart) * [Compatibility Policy](#compatibility-policy) * [Browser Compatibility](#browser-compatibility) * [Node.js Compatibility](#nodejs-compatibility) * [Invalid CSS](#invalid-css) * [Embedded Dart Sass](#embedded-dart-sass) * [Usage](#usage) * [Behavioral Differences from Ruby Sass](#behavioral-differences-from-ruby-sass) ## Using Dart Sass There are a few different ways to install and run Dart Sass, depending on your environment and your needs. ### From Chocolatey or Scoop (Windows) If you use [the Chocolatey package manager](https://chocolatey.org/) or [the Scoop package manager](https://github.com/lukesampson/scoop) for Windows, you can install Dart Sass by running ```cmd choco install sass ``` or ```cmd scoop install sass ``` That'll give you a `sass` executable on your command line that will run Dart Sass. See [the CLI docs][cli] for details. [cli]: https://sass-lang.com/documentation/cli/dart-sass ### From Homebrew (macOS or Linux) If you use [the Homebrew package manager](https://brew.sh/), you can install Dart Sass by running ```sh brew install sass/sass/sass ``` That'll give you a `sass` executable on your command line that will run Dart Sass. ### Standalone You can download the standalone Dart Sass archive for your operating system—containing the Dart VM and the snapshot of the executable—from [the GitHub release page][]. Extract it, [add the directory to your path][], restart your terminal, and the `sass` executable is ready to run! [the GitHub release page]: https://github.com/sass/dart-sass/releases/ [add the directory to your path]: https://katiek2.github.io/path-doc/ ### From npm Dart Sass is available, compiled to JavaScript, [as an npm package][npm]. You can install it globally using `npm install -g sass` which will provide access to the `sass` executable. You can also add it to your project using `npm install --save-dev sass`. This provides the executable as well as a library: [npm]: https://www.npmjs.com/package/sass ```js const sass = require('sass'); const result = sass.compile(scssFilename); // OR // Note that `compileAsync()` is substantially slower than `compile()`. const result = await sass.compileAsync(scssFilename); ``` See [the Sass website][js api] for full API documentation. [js api]: https://sass-lang.com/documentation/js-api #### Dart Sass in the Browser The `sass` npm package can also be run directly in the browser. It's compatible with all major web bundlers as long as you disable renaming (such as [`--keep-names`] in esbuild). You can also import it directly from a browser as an ECMAScript Module without any bundling (assuming `node_modules` is served as well): [`--keep-names`]: https://esbuild.github.io/api/#keep-names ```html <script type="importmap"> { "imports": { "immutable": "./node_modules/immutable/dist/immutable.es.js", "sass": "./node_modules/sass/sass.default.js" } } </script> <!-- Support browsers like Safari 16.3 without import maps support. --> <script async src="https://unpkg.com/es-module-shims@^1.7.0" crossorigin="anonymous"></script> <script type="module"> import * as sass from 'sass'; console.log(sass.compileString(` .box { width: 10px + 15px; } `)); </script> ``` Or from a CDN: ```html <script type="importmap"> { "imports": { "immutable": "https://unpkg.com/immutable@^4.0.0", "sass": "https://unpkg.com/sass@^1.63.0/sass.default.js" } } </script> <!-- Support browsers like Safari 16.3 without import maps support. --> <script async src="https://unpkg.com/es-module-shims@^1.7.0" crossorigin="anonymous"></script> <script type="module"> import * as sass from 'sass'; console.log(sass.compileString(` .box { width: 10px + 15px; } `)); </script> ``` Or even bundled with all its dependencies: ```html <script type="module"> import * as sass from 'https://jspm.dev/sass'; console.log(sass.compileString(` .box { width: 10px + 15px; } `)); </script> ``` Since the browser doesn't have access to the filesystem, the [`compile()`] and `compileAsync()` functions aren't available for it. If you want to load other files, you'll need to pass a [custom importer] to [`compileString()`] or [`compileStringAsync()`]. The [legacy API] is also not supported in the browser. [`compile()`]: https://sass-lang.com/documentation/js-api/functions/compile [`compileAsync()`]: https://sass-lang.com/documentation/js-api/functions/compileAsync [custom importer]: https://sass-lang.com/documentation/js-api/interfaces/stringoptions/#importer [`compileString()`]: https://sass-lang.com/documentation/js-api/functions/compileString [`compileStringAsync()`]: https://sass-lang.com/documentation/js-api/functions/compileStringAsync [legacy API]: #legacy-javascript-api #### Legacy JavaScript API Dart Sass also supports an older JavaScript API that's fully compatible with [Node Sass] (with a few exceptions listed below), with support for both the [`render()`] and [`renderSync()`] functions. This API is considered deprecated and will be removed in Dart Sass 2.0.0, so it should be avoided in new projects. [Node Sass]: https://github.com/sass/node-sass [`render()`]: https://sass-lang.com/documentation/js-api/functions/render [`renderSync()`]: https://sass-lang.com/documentation/js-api/functions/renderSync Sass's support for the legacy JavaScript API has the following limitations: * Only the `"expanded"` and `"compressed"` values of [`outputStyle`] are supported. * Dart Sass doesn't support the [`precision`] option. Dart Sass defaults to a sufficiently high precision for all existing browsers, and making this customizable would make the code substantially less efficient. * Dart Sass doesn't support the [`sourceComments`] option. Source maps are the recommended way of locating the origin of generated selectors. [`outputStyle`]: https://sass-lang.com/documentation/js-api/interfaces/LegacySharedOptions#outputStyle [`precision`]: https://github.com/sass/node-sass#precision [`sourceComments`]: https://github.com/sass/node-sass#sourcecomments #### Using Sass with Jest If you're using [Jest] to run your tests, be aware that it has a [longstanding bug] where its default test environment breaks JavaScript's built-in [`instanceof` operator]. Dart Sass's JS package uses `instanceof` fairly heavily, so in order to avoid breaking Sass you'll need to install [`jest-environment-node-single-context`] and add `testEnvironment: 'jest-environment-node-single-context'` to your Jest config. [Jest]: https://jestjs.io/ [longstanding bug]: https://github.com/facebook/jest/issues/2549 [`instanceof` operator]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/instanceof [`jest-environment-node-single-context`]: https://www.npmjs.com/package/jest-environment-node-single-context ### From Pub If you're a Dart user, you can install Dart Sass globally using `pub global activate sass`, which will provide a `sass` executable. You can also add it to your pubspec and use it as a library. We strongly recommend importing it with the prefix `sass`: ```dart import 'package:sass/sass.dart' as sass; void main(List<String> args) { print(sass.compile(args.first)); } ``` See [the Dart API docs][api] for details. [api]: https://www.dartdocs.org/documentation/sass/latest/sass/sass-library.html #### `sass_api` Package Dart users also have access to more in-depth APIs via the [`sass_api` package]. This provides access to the Sass AST and APIs for resolving Sass loads without running a full compilation. It's separated out into its own package so that it can increase its version number independently of the main `sass` package. [`sass_api` package]: https://pub.dev/packages/sass_api ### From Source Assuming you've already checked out this repository: 1. [Install Dart](https://www.dartlang.org/install). If you download an archive manually rather than using an installer, make sure the SDK's `bin` directory is on your `PATH`. 2. [Install Buf]. This is used to build the protocol buffers for the [embedded compiler]. 3. In this repository, run `dart pub get`. This will install Dart Sass's dependencies. 4. Run `dart run grinder protobuf`. This will download and build the embedded protocol definition. 5. Run `dart bin/sass.dart path/to/file.scss`. [Install Buf]: https://docs.buf.build/installation [embedded compiler]: #embedded-dart-sass That's it! ### In Docker You can install and run Dart Sass within Docker using the following Dockerfile commands: ```Dockerfile # Dart stage FROM bufbuild/buf AS buf FROM dart:stable AS dart # Add your scss files COPY --from=another_stage /app /app # Include Protocol Buffer binary COPY --from=buf /usr/local/bin/buf /usr/local/bin/ WORKDIR /dart-sass RUN git clone https://github.com/sass/dart-sass.git . && \ dart pub get && \ dart run grinder protobuf # This is where you run sass.dart on your scss file(s) RUN dart ./bin/sass.dart /app/sass/example.scss /app/public/css/example.css ``` ## Why Dart? Dart Sass has replaced Ruby Sass as the canonical implementation of the Sass language. We chose Dart because it presented a number of advantages: * It's fast. The Dart VM is highly optimized, and getting faster all the time (for the latest performance numbers, see [`perf.md`][perf]). It's much faster than Ruby, and close to par with C++. * It's portable. The Dart VM has no external dependencies and can compile applications into standalone snapshot files, so we can distribute Dart Sass as only three files (the VM, the snapshot, and a wrapper script). Dart can also be compiled to JavaScript, which makes it easy to distribute Sass through npm, which the majority of our users use already. * It's easy to write. Dart is a higher-level language than C++, which means it doesn't require lots of hassle with memory management and build systems. It's also statically typed, which makes it easier to confidently make large refactors than with Ruby. * It's friendlier to contributors. Dart is substantially easier to learn than Ruby, and many Sass users in Google in particular are already familiar with it. More contributors translates to faster, more consistent development. [perf]: https://github.com/sass/dart-sass/blob/master/perf.md ## Compatibility Policy For the most part, Dart Sass follows [semantic versioning][]. We consider all of the following to be part of the versioned API: [semantic versioning]: https://semver.org/ * The Sass language semantics implemented by Dart Sass. * The Dart API. * The JavaScript API. * The command-line interface. Because Dart Sass has a single version that's shared across the Dart, JavaScript, and standalone distributions, this may mean that we increment the major version number when there are in fact no breaking changes for one or more distributions. However, we will attempt to limit the number of breaking changes we make and group them in as few releases as possible to minimize churn. We strongly encourage users to use [the changelog][] for a full understanding of all the changes in each release. [the changelog]: https://github.com/sass/dart-sass/blob/master/CHANGELOG.md There is one exception where breaking changes may be made outside of a major version revision. It is occasionally the case that CSS adds a feature that's incompatible with existing Sass syntax in some way. Because Sass is committed to full CSS compatibility, we occasionally need to break compatibility with old Sass code in order to remain compatible with CSS. In these cases, we will first release a version of Sass that emits deprecation warnings for any stylesheets whose behavior will change. Then, at least three months after the release of a version with these deprecation warnings, we will release a minor version with the breaking change to the Sass language semantics. ### Browser Compatibility In general, we consider any change to Dart Sass's CSS output that would cause that CSS to stop working in a real browser to be a breaking change. However, there are some cases where such a change would have substantial benefits and would only negatively affect a small minority of rarely-used browsers. We don't want to have to block such a change on a major version release. As such, if a change would break compatibility with less than 2% of the global market share of browser according to [StatCounter GlobalStats][], we may release a minor version of Dart Sass with that change. [StatCounter GlobalStats]: https://gs.statcounter.com/ ### Node.js Compatibility We consider dropping support for a given version of Node.js to be a breaking change *as long as* that version is still supported by Node.js. This means that releases listed as Current, Active LTS, or Maintenance LTS according to [the Node.js release page][]. Once a Node.js version is out of LTS, Dart Sass considers itself free to break support if necessary. [the Node.js release page]: https://nodejs.org/en/about/previous-releases ### Invalid CSS Changes to the behavior of Sass stylesheets that produce invalid CSS output are _not_ considered breaking changes. Such changes are almost always necessary when adding support for new CSS features, and delaying all such features until a new major version would be unduly burdensome for most users. For example, when Sass began parsing `calc()` expressions, the invalid expression `calc(1 +)` became a Sass error where before it was passed through as-is. This was not considered a breaking change, because `calc(1 +)` was never valid CSS to begin with. ## Embedded Dart Sass Dart Sass includes an implementation of the compiler side of the [Embedded Sass protocol]. It's designed to be embedded in a host language, which then exposes an API for users to invoke Sass and define custom functions and importers. [Embedded Sass protocol]: https://github.com/sass/sass/blob/main/spec/embedded-protocol.md ### Usage * `sass --embedded` starts the embedded compiler and listens on stdin. * `sass --embedded --version` prints `versionResponse` with `id = 0` in JSON and exits. The `--embedded` command-line flag is not available when you install Dart Sass as an [npm package]. No other command-line flags are supported with `--embedded`. [npm package]: #from-npm ## Behavioral Differences from Ruby Sass There are a few intentional behavioral differences between Dart Sass and Ruby Sass. These are generally places where Ruby Sass has an undesired behavior, and it's substantially easier to implement the correct behavior than it would be to implement compatible behavior. These should all have tracking bugs against Ruby Sass to update the reference behavior. 1. `@extend` only accepts simple selectors, as does the second argument of `selector-extend()`. See [issue 1599][]. 2. Subject selectors are not supported. See [issue 1126][]. 3. Pseudo selector arguments are parsed as `<declaration-value>`s rather than having a more limited custom parsing. See [issue 2120][]. 4. The numeric precision is set to 10. See [issue 1122][]. 5. The indented syntax parser is more flexible: it doesn't require consistent indentation across the whole document. See [issue 2176][]. 6. Colors do not support channel-by-channel arithmetic. See [issue 2144][]. 7. Unitless numbers aren't `==` to unit numbers with the same value. In addition, map keys follow the same logic as `==`-equality. See [issue 1496][]. 8. `rgba()` and `hsla()` alpha values with percentage units are interpreted as percentages. Other units are forbidden. See [issue 1525][]. 9. Too many variable arguments passed to a function is an error. See [issue 1408][]. 10. Allow `@extend` to reach outside a media query if there's an identical `@extend` defined outside that query. This isn't tracked explicitly, because it'll be irrelevant when [issue 1050][] is fixed. 11. Some selector pseudos containing placeholder selectors will be compiled where they wouldn't be in Ruby Sass. This better matches the semantics of the selectors in question, and is more efficient. See [issue 2228][]. 12. The old-style `:property value` syntax is not supported in the indented syntax. See [issue 2245][]. 13. The reference combinator is not supported. See [issue 303][]. 14. Universal selector unification is symmetrical. See [issue 2247][]. 15. `@extend` doesn't produce an error if it matches but fails to unify. See [issue 2250][]. 16. Dart Sass currently only supports UTF-8 documents. We'd like to support more, but Dart currently doesn't support them. See [dart-lang/sdk#11744][], for example. [issue 1599]: https://github.com/sass/sass/issues/1599 [issue 1126]: https://github.com/sass/sass/issues/1126 [issue 2120]: https://github.com/sass/sass/issues/2120 [issue 1122]: https://github.com/sass/sass/issues/1122 [issue 2176]: https://github.com/sass/sass/issues/2176 [issue 2144]: https://github.com/sass/sass/issues/2144 [issue 1496]: https://github.com/sass/sass/issues/1496 [issue 1525]: https://github.com/sass/sass/issues/1525 [issue 1408]: https://github.com/sass/sass/issues/1408 [issue 1050]: https://github.com/sass/sass/issues/1050 [issue 2228]: https://github.com/sass/sass/issues/2228 [issue 2245]: https://github.com/sass/sass/issues/2245 [issue 303]: https://github.com/sass/sass/issues/303 [issue 2247]: https://github.com/sass/sass/issues/2247 [issue 2250]: https://github.com/sass/sass/issues/2250 [dart-lang/sdk#11744]: https://github.com/dart-lang/sdk/issues/11744 Disclaimer: this is not an official Google product. ", Assign "at most 3 tags" to the expected json: {"id":"11179","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"