Product
Introducing License Enforcement in Socket
Ensure open-source compliance with Socket’s License Enforcement Beta. Set up your License Policy and secure your software!
The sass npm package is a preprocessor scripting language that is interpreted or compiled into Cascading Style Sheets (CSS). It enables developers to use variables, nested rules, mixins, functions, and more, which can help in writing CSS in a more structured and maintainable way.
Variables
Variables allow you to store values that you can reuse throughout your stylesheet.
$primary-color: #333;
body {
color: $primary-color;
}
Nesting
Nesting enables you to nest your CSS selectors in a way that follows the same visual hierarchy of your HTML.
nav {
ul {
margin: 0;
padding: 0;
list-style: none;
}
li { display: inline-block; }
a {
display: block;
padding: 6px 12px;
text-decoration: none;
}
}
Partials and Import
Partials are Sass files named with a leading underscore. You can import these partials into other Sass files to modularize your CSS and help keep things easier to maintain.
// _reset.scss
html,
body,
ul,
ol {
margin: 0;
padding: 0;
}
// main.scss
@import 'reset';
body {
font-family: sans-serif;
}
Mixins
Mixins allow you to define styles that can be reused throughout your stylesheet.
@mixin border-radius($radius) {
-webkit-border-radius: $radius;
-moz-border-radius: $radius;
-ms-border-radius: $radius;
border-radius: $radius;
}
.box { @include border-radius(10px); }
Extend/Inheritance
Extend/Inheritance lets you share a set of CSS properties from one selector to another.
.message {
border: 1px solid #ccc;
padding: 10px;
color: #333;
}
.success {
@extend .message;
border-color: green;
}
Operators
Sass supports standard math operators like +, -, *, /, and %.
.container {
width: 100%;
}
.article {
width: 600px / 960px * 100%;
}
Less is a backward-compatible language extension for CSS. It provides similar features to Sass, such as variables, mixins, and nesting. However, Less uses JavaScript for compilation, whereas Sass was originally written in Ruby and now primarily uses a C implementation (Dart Sass).
Stylus is a preprocessor that offers a more flexible syntax than Sass and Less, with optional semicolons and braces. It also provides powerful features like variable interpolation and iteration. Stylus can be more terse and expressive in some cases but might have a steeper learning curve for those used to more traditional CSS syntax.
PostCSS is a tool for transforming CSS with JavaScript plugins. While it is not a preprocessor in the traditional sense, it can be used to achieve many of the same goals as Sass through its extensive plugin ecosystem. PostCSS is highly customizable and can be tailored to specific build processes and requirements.
A Dart implementation of Sass. Sass makes CSS fun again.
There are a few different ways to install and run Dart Sass, depending on your environment and your needs.
If you use the Chocolatey package manager for Windows, you can install Dart Sass by running
choco install sass -prerelease
That'll give you a sass
executable on your command line that will run Dart
Sass.
You can download the standalone Dart Sass archive for your operating
system—containing the Dart VM and the snapshot of the Sass library—from
the release page. Extract it, add the directory to your path, and
the dart-sass
executable is ready to run!
To add the directory to your path on Windows, open the Control Panel, then
search for and select "edit environment variables". Find the variable named
PATH
, click Edit, add ;C:\path\to\dart-sass
to the end of the value, then
click OK.
On more Unix-y systems, edit your shell configuration file (usually ~/.bashrc
or ~/.profile
) and add at the end:
export PATH=$PATH:/path/to/dart-sass
Regardless of your OS, you'll need to restart your terminal in order for this configuration to take effect.
Dart Sass is available, compiled to JavaScript, as an npm package. You
can install it globally using npm install -g sass
, or to your project using
npm install sass
. This provides a sass
executable as well as a library:
var sass = require('sass');
sass.render({file: scss_filename}, function(err, result) { /* ... */ });
// OR
var result = sass.renderSync({file: scss_filename});
See below for details on Dart Sass's JavaScript API.
If you're a Dart user, you can install Dart Sass globally using pub global activate sass ^1.0.0-alpha
, which will provide a dart-sass
executable. You can
also add it to your pubspec and use it as a library:
import 'package:sass/sass.dart' as sass;
void main(List<String> args) {
print(sass.compile(args.first));
}
See the Dart API docs for details.
Assuming you've already checked out this repository:
Install Dart. If you download it
manually, make sure the SDK's bin
directory is on your PATH
.
In this repository, run pub get
. This will install Dart Sass's
dependencies.
Run dart bin/sass.dart path/to/file.scss
.
That's it!
When installed via NPM, Dart Sass supports a JavaScript API that aims to be
compatible with Node Sass. Full
compatibility is a work in progress, but Dart Sass currently supports the
render()
and renderSync()
functions with the following options:
file
data
includePaths
indentedSyntax
indentType
indentWidth
linefeed
"expanded"
value of
outputStyle
is supported.importer
is supported, but only for importers that return
values synchronously. The done()
callback is currently not passed to any
importers, even when running the asynchronous render()
function.The following options are not yet supported, but are intended:
No support is intended for the following options:
precision
. Dart Sass defaults
to a sufficiently high precision for all existing browsers, and making this
customizable would make the code substantially less efficient.
sourceComments
. Once
Dart Sass supports source maps, that will be the recommended way of locating
the origin of generated selectors.
Dart Sass is intended to eventually replace Ruby Sass as the canonical implementation of the Sass language. It has 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
). It's much faster
than Ruby, and not too far away from C.
It's portable. The Dart VM has no external dependencies and can compile applications into standalone snapshot files, so a fully-functional Dart Sass could be distributed as only three files (the VM, the snapshot, and a wrapper script). Dart can also be compiled to JavaScript, which would make it easy to distribute Sass through npm or other JS package managers.
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.
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.
@extend
only accepts simple selectors, as does the second argument of
selector-extend()
. See issue 1599.
Subject selectors are not supported. See issue 1126.
Pseudo selector arguments are parsed as <declaration-value>
s rather than
having a more limited custom parsing. See issue 2120.
The numeric precision is set to 10. See issue 1122.
The indented syntax parser is more flexible: it doesn't require consistent indentation across the whole document. See issue 2176.
Colors do not support channel-by-channel arithmetic. See issue 2144.
Unitless numbers aren't ==
to unit numbers with the same value. In
addition, map keys follow the same logic as ==
-equality. See
issue 1496.
rgba()
and hsla()
alpha values with percentage units are interpreted as
percentages. Other units are forbidden. See issue 1525.
Too many variable arguments passed to a function is an error. See issue 1408.
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.
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.
The old-style :property value
syntax is not supported in the indented
syntax. See issue 2245.
The reference combinator is not supported. See issue 303.
Universal selector unification is symmetrical. See issue 2247.
@extend
doesn't produce an error if it matches but fails to unify. See
issue 2250.
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.
Disclaimer: this is not an official Google product.
1.0.0-beta.3
Properly parse numbers with exponents.
Don't crash when evaluating CSS variables whose names are entirely
interpolated (for example, #{--foo}: ...
).
importer
option to render()
and renderSync()
.
Only synchronous importers are currently supported.Added an Importer
class. This can be extended by users to provide support
for custom resolution for @import
rules.
Added built-in FilesystemImporter
and PackageImporter
implementations that
support resolving file:
and package:
URLs, respectively.
Added an importers
argument to the compile()
and compileString()
functions that provides Importer
s to use when resolving @import
rules.
Added a loadPaths
argument to the compile()
and compileString()
functions that provides paths to search for stylesheets when resolving
@import
rules. This is a shorthand for passing FilesystemImporter
s to the
importers
argument.
FAQs
A pure JavaScript implementation of Sass.
The npm package sass receives a total of 11,496,031 weekly downloads. As such, sass popularity was classified as popular.
We found that sass demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 3 open source maintainers collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Product
Ensure open-source compliance with Socket’s License Enforcement Beta. Set up your License Policy and secure your software!
Product
We're launching a new set of license analysis and compliance features for analyzing, managing, and complying with licenses across a range of supported languages and ecosystems.
Product
We're excited to introduce Socket Optimize, a powerful CLI command to secure open source dependencies with tested, optimized package overrides.