@use

Compatibility:
Dart Sass
since 1.23.0
LibSass
Ruby Sass

Only Dart Sass currently supports @use. Users of other implementations must use the @import rule instead.

The @use rule loads mixins, functions, and variables from other Sass stylesheets, and combines CSS from multiple stylesheets together. Stylesheets loaded by @use are called "modules". Sass also provides built-in modules full of useful functions.

The simplest @use rule is written @use "<url>", which loads the module at the given URL. Any styles loaded this way will be included exactly once in the compiled CSS output, no matter how many times those styles are loaded.

⚠️ Heads up!

A stylesheet’s @use rules must come before any rules other than @forward, including style rules. However, you can declare variables before @use rules to use when configuring modules.

SCSS Syntax

// foundation/_code.scss
code {
  padding: .25em;
  line-height: 0;
}
// foundation/_lists.scss
ul, ol {
  text-align: left;

  & & {
    padding: {
      bottom: 0;
      left: 0;
    }
  }
}
// style.scss
@use 'foundation/code';
@use 'foundation/lists';

Sass Syntax

// foundation/_code.sass
code
  padding: .25em
  line-height: 0

// foundation/_lists.sass
ul, ol
  text-align: left

  & &
    padding:
      bottom: 0
      left: 0



// style.sass
@use 'foundation/code'
@use 'foundation/lists'

CSS Output

code {
  padding: .25em;
  line-height: 0;
}

ul, ol {
  text-align: left;
}
ul ul, ol ol {
  padding-bottom: 0;
  padding-left: 0;
}











Loading MembersLoading Members permalink

You can access variables, functions, and mixins from another module by writing <namespace>.<variable>, <namespace>.<function>(), or @include <namespace>.<mixin>(). By default, the namespace is just the last component of the module’s URL.

Members (variables, functions, and mixins) loaded with @use are only visible in the stylesheet that loads them. Other stylesheets will need to write their own @use rules if they also want to access them. This helps make it easy to figure out exactly where each member is coming from. If you want to load members from many files at once, you can use the @forward rule to forward them all from one shared file.

💡 Fun fact:

Because @use adds namespaces to member names, it’s safe to choose very simple names like $radius or $width when writing a stylesheet. This is different from the old @import rule, which encouraged that users write long names like $mat-corner-radius to avoid conflicts with other libraries, and it helps keep your stylesheets clear and easy to read!

SCSS Syntax

// src/_corners.scss
$radius: 3px;

@mixin rounded {
  border-radius: $radius;
}
// style.scss
@use "src/corners";

.button {
  @include corners.rounded;
  padding: 5px + corners.$radius;
}

Sass Syntax

// src/_corners.sass
$radius: 3px

@mixin rounded
  border-radius: $radius

// style.sass
@use "src/corners"

.button
  @include corners.rounded
  padding: 5px + corners.$radius

CSS Output

.button {
  border-radius: 3px;
  padding: 8px;
}











Choosing a NamespaceChoosing a Namespace permalink

By default, a module’s namespace is just the last component of its URL without a file extension. However, sometimes you might want to choose a different namespace—you might want to use a shorter name for a module you refer to a lot, or you might be loading multiple modules with the same filename. You can do this by writing @use "<url>" as <namespace>.

SCSS Syntax

// src/_corners.scss
$radius: 3px;

@mixin rounded {
  border-radius: $radius;
}
// style.scss
@use "src/corners" as c;

.button {
  @include c.rounded;
  padding: 5px + c.$radius;
}

Sass Syntax

// src/_corners.sass
$radius: 3px

@mixin rounded
  border-radius: $radius

// style.sass
@use "src/corners" as c

.button
  @include c.rounded
  padding: 5px + c.$radius

CSS Output

.button {
  border-radius: 3px;
  padding: 8px;
}











You can even load a module without a namespace by writing @use "<url>" as *. We recommend you only do this for stylesheets written by you, though; otherwise, they may introduce new members that cause name conflicts!

SCSS Syntax

// src/_corners.scss
$radius: 3px;

@mixin rounded {
  border-radius: $radius;
}
// style.scss
@use "src/corners" as *;

.button {
  @include rounded;
  padding: 5px + $radius;
}

Sass Syntax

// src/_corners.sass
$radius: 3px

@mixin rounded
  border-radius: $radius

// style.sass
@use "src/corners" as *

.button
  @include rounded
  padding: 5px + $radius

CSS Output

.button {
  border-radius: 3px;
  padding: 8px;
}











Private MembersPrivate Members permalink

As a stylesheet author, you may not want all the members you define to be available outside your stylesheet. Sass makes it easy to define a private member by starting its name with either - or _. These members will work just like normal within the stylesheet that defines them, but they won’t be part of a module’s public API. That means stylesheets that load your module can’t see them!

💡 Fun fact:

If you want to make a member private to an entire package rather than just a single module, just don’t forward its module from any of your package’s entrypoints (the stylesheets you tell your users to load to use your package). You can even hide that member while forwarding the rest of its module!

SCSS Syntax

// src/_corners.scss
$-radius: 3px;

@mixin rounded {
  border-radius: $-radius;
}
// style.scss
@use "src/corners";

.button {
  @include corners.rounded;

  // This is an error! $-radius isn't visible outside of `_corners.scss`.
  padding: 5px + corners.$-radius;
}

Sass Syntax

// src/_corners.sass
$-radius: 3px

@mixin rounded
  border-radius: $-radius

// style.sass
@use "src/corners"

.button
  @include corners.rounded

  // This is an error! $-radius isn't visible outside of `_corners.scss`.
  padding: 5px + corners.$-radius

ConfigurationConfiguration permalink

A stylesheet can define variables with the !default flag to make them configurable. To load a module with configuration, write @use <url> with (<variable>: <value>, <variable>: <value>). The configured values will override the variables’ default values.

SCSS Syntax

// _library.scss
$black: #000 !default;
$border-radius: 0.25rem !default;
$box-shadow: 0 0.5rem 1rem rgba($black, 0.15) !default;

code {
  border-radius: $border-radius;
  box-shadow: $box-shadow;
}
// style.scss
@use 'library' with (
  $black: #222,
  $border-radius: 0.1rem
);

Sass Syntax

// _library.sass
$black: #000 !default
$border-radius: 0.25rem !default
$box-shadow: 0 0.5rem 1rem rgba($black, 0.15) !default

code
  border-radius: $border-radius
  box-shadow: $box-shadow

// style.sass
@use 'library' with ($black: #222, $border-radius: 0.1rem)



CSS Output

code {
  border-radius: 0.1rem;
  box-shadow: 0 0.5rem 1rem rgba(34, 34, 34, 0.15);
}












With MixinsWith Mixins permalink

Configuring modules with @use ... with can be very handy, especially when using libraries that were originally written to work with the @import rule. But it’s not particularly flexible, and we don’t recommend it for more advanced use-cases. If you find yourself wanting to configure many variables at once, pass maps as configuration, or update the configuration after the module is loaded, consider writing a mixin to set your variables instead and another mixin to inject your styles.

SCSS Syntax

// _library.scss
$-black: #000;
$-border-radius: 0.25rem;
$-box-shadow: null;

/// If the user has configured `$-box-shadow`, returns their configured value.
/// Otherwise returns a value derived from `$-black`.
@function -box-shadow() {
  @return $-box-shadow or (0 0.5rem 1rem rgba($-black, 0.15));
}

@mixin configure($black: null, $border-radius: null, $box-shadow: null) {
  @if $black {
    $-black: $black !global;
  }
  @if $border-radius {
    $-border-radius: $border-radius !global;
  }
  @if $box-shadow {
    $-box-shadow: $box-shadow !global;
  }
}

@mixin styles {
  code {
    border-radius: $-border-radius;
    box-shadow: -box-shadow();
  }
}
// style.scss
@use 'library';

@include library.configure(
  $black: #222,
  $border-radius: 0.1rem
);

@include library.styles;

Sass Syntax

// _library.sass
$-black: #000
$-border-radius: 0.25rem
$-box-shadow: null

/// If the user has configured `$-box-shadow`, returns their configured value.
/// Otherwise returns a value derived from `$-black`.
@function -box-shadow()
  @return $-box-shadow or (0 0.5rem 1rem rgba($-black, 0.15))


@mixin configure($black: null, $border-radius: null, $box-shadow: null)
  @if $black
    $-black: $black !global
  @if $border-radius
    $-border-radius: $border-radius !global
  @if $box-shadow
    $-box-shadow: $box-shadow !global


@mixin styles
  code
    border-radius: $-border-radius
    box-shadow: -box-shadow()





// style.sass
@use 'library'
@include library.configure($black: #222, $border-radius: 0.1rem)
@include library.styles





CSS Output

code {
  border-radius: 0.1rem;
  box-shadow: 0 0.5rem 1rem rgba(34, 34, 34, 0.15);
}




































Reassigning VariablesReassigning Variables permalink

After loading a module, you can reassign its variables.

SCSS Syntax

// _library.scss
$color: red;
// _override.scss
@use 'library';
library.$color: blue;
// style.scss
@use 'library';
@use 'override';
@debug library.$color;  //=> blue

Sass Syntax

// _library.sass
$color: red
// _override.sass
@use 'library'
library.$color: blue
// style.sass
@use 'library'
@use 'override'
@debug library.$color  //=> blue

This even works if you import a module without a namespace using as *. Assigning to a variable name defined in that module will overwrite its value in that module.

⚠️ Heads up!

Built-in module variables (such as math.$pi) cannot be reassigned.

Finding the ModuleFinding the Module permalink

It wouldn’t be any fun to write out absolute URLs for every stylesheet you load, so Sass’s algorithm for finding a module makes it a little easier. For starters, you don’t have to explicitly write out the extension of the file you want to load; @use "variables" will automatically load variables.scss, variables.sass, or variables.css.

⚠️ Heads up!

To ensure that stylesheets work on every operating system, Sass loads files by URL, not by file path. This means you need to use forward slashes, not backslashes, even on Windows.

Load PathsLoad Paths permalink

All Sass implementations allow users to provide load paths: paths on the filesystem that Sass will look in when locating modules. For example, if you pass node_modules/susy/sass as a load path, you can use @use "susy" to load node_modules/susy/sass/susy.scss (although pkg: URLs are a better way to handle that).

Modules will always be loaded relative to the current file first, though. Load paths will only be used if no relative file exists that matches the module’s URL. This ensures that you can’t accidentally mess up your relative imports when you add a new library.

💡 Fun fact:

Unlike some other languages, Sass doesn’t require that you use ./ for relative imports. Relative imports are always available.

PartialsPartials permalink

As a convention, Sass files that are only meant to be loaded as modules, not compiled on their own, begin with _ (as in _code.scss). These are called partials, and they tell Sass tools not to try to compile those files on their own. You can leave off the _ when importing a partial.

Index FilesIndex Files permalink

If you write an _index.scss or _index.sass in a folder, the index file will be loaded automatically when you load the URL for the folder itself.

SCSS Syntax

// foundation/_code.scss
code {
  padding: .25em;
  line-height: 0;
}
// foundation/_lists.scss
ul, ol {
  text-align: left;

  & & {
    padding: {
      bottom: 0;
      left: 0;
    }
  }
}
// foundation/_index.scss
@use 'code';
@use 'lists';
// style.scss
@use 'foundation';

Sass Syntax

// foundation/_code.sass
code
  padding: .25em
  line-height: 0

// foundation/_lists.sass
ul, ol
  text-align: left

  & &
    padding:
      bottom: 0
      left: 0



// foundation/_index.sass
@use 'code'
@use 'lists'
// style.sass
@use 'foundation'

CSS Output

code {
  padding: .25em;
  line-height: 0;
}

ul, ol {
  text-align: left;
}
ul ul, ol ol {
  padding-bottom: 0;
  padding-left: 0;
}















pkg: URLspkg: URLs permalink

Sass uses the pkg: URL scheme to load stylesheets distributed by various package managers. Since Sass is used in the context of many different programming languages with different package management conventions, pkg: URLs have almost no set meaning. Instead, users are encouraged to implement custom importers (using the JS API or the Embedded Sass protocol) that resolve these URLs using the native package manager’s logic.

This allows pkg: URLs and the stylesheets that use them to be portable across different language ecosystems. Whether you’re installing a Sass library via npm (for which Sass provides a built-in pkg: importer) or the most obscure package manager you can find, if you write @use 'pkg:library' it’ll do the right thing.

💡 Fun fact:

pkg: URLs aren’t just for @use. You can use them anywhere you can load a Sass file, including @forward, meta.load-css(), and even the old @import rule.

Rules for a pkg: ImporterRules for a pkg: Importer permalink

There are a few common rules that Sass expects all pkg: importers to follow. These rules help ensure that pkg: URLs are handled consistently across all package managers, so that stylesheets are as portable as possible.

In addition to the standard rules for custom importers, a pkg: importer must only handle non-canonical URLs that:

  • have the scheme pkg, and
  • whose path begins with a package name, and
  • are optionally followed by a path, with path segments separated with a forward slash.

The package name may contain forward slashes, depending on whether the particular package manager supports that. For example, npm allows package names like @namespace/name. Note that package names that contain non-alphanumeric characters may be less portable across different package managers.

pkg: importers must reject the following patterns:

  • A URL whose path begins with /.
  • A URL with non-empty/null username, password, host, port, query, or fragment.

If pkg: importer encounters a URL that violates its own package manager’s conventions but not the above rules, it should just decline to load that URL rather than throwing an error. This allows users to use multiple pkg: importers at once if necessary.

Node.js Package ImporterNode.js Package Importer permalink

Compatibility:
Dart Sass
since 1.71.0
LibSass
Ruby Sass

Because Sass is most widely-used alongside the Node.js ecosystem, it comes with a pkg: importer that uses the same algorithm as Node.js to load Sass stylesheets. This isn’t available by default, but it’s easy to turn on:

If you load a pkg: URL, the Node.js pkg: importer will look at its package.json file to determine which Sass file to load. It will check in order:

  • The "exports" field, with the conditions "sass", "style", and "default". This is the recommended way for packages to expose Sass entrypoints going forward.

  • The "sass" field or the "style" field, which should be a path to a Sass file. This only works if the pkg: URL doesn’t have a subpath—pkg:library will load the file listed in the "sass" field, but pkg:library/button will load button.scss from the root of the package.

  • The index file at the root of the package This also only works if the pkg: URL doesn’t have a subpath.

The Node.js pkg: importer supports the full range of "exports" features, so you can also specify different locations for different subpaths (note that the key must include the file extension):

{
  "exports": {
    ".": {
      "sass": "styles/index.scss",
    },
    "./button.scss": {
      "sass": "styles/button.scss",
    },
    "./accordion.scss": {
      "sass": "styles/accordion.scss",
    }
  }
}

…or even patterns:

{
  "exports": {
    ".": {
      "sass": "styles/index.scss",
    },
    "./*.scss": {
      "sass": "styles/*.scss",
    },
  }
}

Loading CSSLoading CSS permalink

In addition to loading .sass and .scss files, Sass can load plain old .css files.

SCSS Syntax

// code.css
code {
  padding: .25em;
  line-height: 0;
}
// style.scss
@use 'code';

Sass Syntax

// code.css
code {
  padding: .25em;
  line-height: 0;
}
// style.sass
@use 'code'

CSS Output

code {
  padding: .25em;
  line-height: 0;
}





CSS files loaded as modules don’t allow any special Sass features and so can’t expose any Sass variables, functions, or mixins. In order to make sure authors don’t accidentally write Sass in their CSS, all Sass features that aren’t also valid CSS will produce errors. Otherwise, the CSS will be rendered as-is. It can even be extended!

Differences From @importDifferences From @import permalink

The @use rule is intended to replace the old @import rule, but it’s intentionally designed to work differently. Here are some major differences between the two:

  • @use only makes variables, functions, and mixins available within the scope of the current file. It never adds them to the global scope. This makes it easy to figure out where each name your Sass file references comes from, and means you can use shorter names without any risk of collision.

  • @use only ever loads each file once. This ensures you don’t end up accidentally duplicating your dependencies’ CSS many times over.

  • @use must appear at the beginning your file, and cannot be nested in style rules.

  • Each @use rule can only have one URL.

  • @use requires quotes around its URL, even when using the indented syntax.