with no native code or external dependencies. It provides a command-line
executable and a Node.js API.
You can install Sass 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
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 for full API documentation.
Node Sass (with a few exceptions listed below), with support for both the
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.
Dart Sass doesn't support the
precisionoption. 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
sourceCommentsoption. Source maps are the recommended way of locating the origin of generated selectors.
Node Sass, which is a wrapper around LibSass, the C++ implementation of Sass. Node Sass supports the same API as this package and is also faster (although it's usually a little slower than Dart Sass). However, it requires a native library which may be difficult to install, and it's generally slower to add features and fix bugs.
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.
@extendonly 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.
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.
@extendto reach outside a media query if there's an identical
@extenddefined 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.
:property valuesyntax 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.
@extenddoesn'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.