sass-site/meta.md at 0ea57c315306d1c746c9240a92f83e22f3e4f656

mirror of https://github.com/danog/sass-site.git synced 2024-12-04 10:28:22 +01:00

Jonny Gerig Meyer 95b50526f9

2023-06-22 14:28:43 -04:00

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title
sass:meta

{% render 'doc_snippets/built-in-module-status' %}

Mixins

{% function 'meta.load-css($url, $with: null)' %} {% compatibility 'dart: "1.23.0"', 'libsass: false', 'ruby: false' %} Only Dart Sass currently supports this mixin. {% endcompatibility %}

Loads the module at $url and includes its CSS as though it were written as the contents of this mixin. The $with parameter provides configuration for the modules; if it's passed, it must be a map from variable names (without $) to the values of those variables to use in the loaded module.

If $url is relative, it's interpreted as relative to the file in which meta.load-css() is included.

Like the @use rule:

This will only evaluate the given module once, even if it's loaded multiple times in different ways.
This cannot provide configuration to a module that's already been loaded, whether or not it was already loaded with configuration.

Unlike the @use rule:

This doesn't make any members from the loaded module available in the current module.
This can be used anywhere in a stylesheet. It can even be nested within style rules to create nested styles!
The module URL being loaded can come from a variable and include interpolation.

{% headsUp %} The $url parameter should be a string containing a URL like you'd pass to the @use rule. It shouldn't be a CSS url()! {% endheadsUp %}

{% codeExample 'load-css', false %} // dark-theme/_code.scss $border-contrast: false !default;

code {
  background-color: #6b717f;
  color: #d2e1dd;
  @if $border-contrast {
    border-color: #dadbdf;
  }
}
---
// style.scss
@use "sass:meta";

body.dark {
  @include meta.load-css("dark-theme/code",
      $with: ("border-contrast": true));
}
===
// dark-theme/_code.sass
$border-contrast: false !default

code
  background-color: #6b717f
  color: #d2e1dd
  @if $border-contrast
    border-color: #dadbdf
---
// style.sass
@use "sass:meta"

body.dark
  $configuration: ("border-contrast": true)
  @include meta.load-css("dark-theme/code", $with: $configuration)
===
body.dark code {
  background-color: #6b717f;
  color: #d2e1dd;
  border-color: #dadbdf;
}

{% endcodeExample %} {% endfunction %}

Functions

{% function 'meta.calc-args($calc)', 'returns:list' %} {% compatibility 'dart: "1.40.0"', 'libsass: false', 'ruby: false' %}{% endcompatibility %}

Returns the arguments for the given calculation.

If an argument is a number or a nested calculation, it's returned as that type. Otherwise, it's returned as an unquoted string.

{% codeExample 'calc-args', false %} @debug meta.calc-args(calc(100px + 10%)); // unquote("100px + 10%") @debug meta.calc-args(clamp(50px, var(--width), 1000px)); // 50px, unquote("var(--width)"), 1000px === @debug meta.calc-args(calc(100px + 10%)) // unquote("100px + 10%") @debug meta.calc-args(clamp(50px, var(--width), 1000px)) // 50px, unquote("var(--width)"), 1000px {% endcodeExample %} {% endfunction %}

{% function 'meta.calc-name($calc)', 'returns:quoted string' %} {% compatibility 'dart: "1.40.0"', 'libsass: false', 'ruby: false' %}{% endcompatibility %}

Returns the name of the given calculation.

{% codeExample 'calc-name', false %} @debug meta.calc-name(calc(100px + 10%)); // "calc" @debug meta.calc-name(clamp(50px, var(--width), 1000px)); // "clamp" === @debug meta.calc-name(calc(100px + 10%)) // "calc" @debug meta.calc-name(clamp(50px, var(--width), 1000px)) // "clamp" {% endcodeExample %} {% endfunction %}

{% function 'meta.call($function, $args...)', 'call($function, $args...)' %} {% render 'doc_snippets/call-impl-status' %}

Invokes $function with $args and returns the result.

The $function should be a function returned by meta.get-function().

{% render 'code_snippets/example-first-class-function' %} {% endfunction %}

{% function 'meta.content-exists()', 'content-exists()', 'returns:boolean' %} Returns whether the current mixin was passed a @content block.

Throws an error if called outside of a mixin.

{% codeExample 'content-exists', false %} @mixin debug-content-exists { @debug meta.content-exists(); @content; }

@include debug-content-exists; // false
@include debug-content-exists { // true
  // Content!
}
===
@mixin debug-content-exists
  @debug meta.content-exists()
  @content


@include debug-content-exists  // false
@include debug-content-exists   // true
  // Content!

{% endcodeExample %} {% endfunction %}

{% function 'meta.feature-exists($feature)', 'feature-exists($feature)', 'returns:boolean' %} Returns whether the current Sass implementation supports $feature.

The $feature must be a string. The currently recognized features are:

global-variable-shadowing, which means that a local variable will shadow a global variable unless it has the !global flag.
extend-selector-pseudoclass, which means that the @extend rule will affect selectors nested in pseudo-classes like :not().
units-level3, which means that unit arithmetic supports units defined in CSS Values and Units Level 3.
at-error, which means that the @error rule is supported.
custom-property, which means that custom property declaration values don't support any expressions other than interpolation.

Returns false for any unrecognized $feature.

{% codeExample 'feature-exists', false %} @debug meta.feature-exists("at-error"); // true @debug meta.feature-exists("unrecognized"); // false === @debug meta.feature-exists("at-error") // true @debug meta.feature-exists("unrecognized") // false {% endcodeExample %} {% endfunction %}

{% function 'meta.function-exists($name, $module: null)', 'function-exists($name)', 'returns:boolean' %} Returns whether a function named $name is defined, either as a built-in function or a user-defined function.

If $module is passed, this also checks the module named $module for the function definition. $module must be a string matching the namespace of a @use rule in the current file.

{% codeExample 'function-exists', false %} @use "sass:math";

@debug meta.function-exists("div", "math"); // true
@debug meta.function-exists("scale-color"); // true
@debug meta.function-exists("add"); // false

@function add($num1, $num2) {
  @return $num1 + $num2;
}
@debug meta.function-exists("add"); // true
===
@use "sass:math"

@debug meta.function-exists("div", "math")  // true
@debug meta.function-exists("scale-color")  // true
@debug meta.function-exists("add")  // false

@function add($num1, $num2)
  @return $num1 + $num2

@debug meta.function-exists("add")  // true

{% endcodeExample %} {% endfunction %}

{% function 'meta.get-function($name, $css: false, $module: null)', 'get-function($name, $css: false, $module: null)', 'returns:function' %} Returns the function named $name.

If $module is null, this returns the function named $name without a namespace (including global built-in functions). Otherwise, $module must be a string matching the namespace of a @use rule in the current file, in which case this returns the function in that module named $name.

By default, this throws an error if $name doesn't refer to Sass function. However, if $css is true, it instead returns a plain CSS function.

The returned function can be called using meta.call().

{% render 'code_snippets/example-first-class-function' %} {% endfunction %}

{% function 'meta.global-variable-exists($name, $module: null)', 'global-variable-exists($name, $module: null)', 'returns:boolean' %} Returns whether a global variable named $name (without the $) exists.

If $module is null, this returns whether a variable named $name without a namespace exists. Otherwise, $module must be a string matching the namespace of a @use rule in the current file, in which case this returns whether that module has a variable named $name.

See also meta.variable-exists().

{% codeExample 'global-variable-exists', false %} @debug meta.global-variable-exists("var1"); // false

$var1: value;
@debug meta.global-variable-exists("var1"); // true

h1 {
  // $var2 is local.
  $var2: value;
  @debug meta.global-variable-exists("var2"); // false
}
===
@debug meta.global-variable-exists("var1")  // false

$var1: value
@debug meta.global-variable-exists("var1")  // true

h1
  // $var2 is local.
  $var2: value
  @debug meta.global-variable-exists("var2")  // false

{% endcodeExample %} {% endfunction %}

{% function 'meta.inspect($value)', 'inspect($value)', 'returns:unquoted string' %} Returns a string representation of $value.

Returns a representation of any Sass value, not just those that can be represented in CSS. As such, its return value is not guaranteed to be valid CSS.

{% headsUp %} This function is intended for debugging; its output format is not guaranteed to be consistent across Sass versions or implementations. {% endheadsUp %}

{% codeExample 'inspect', false %} @debug meta.inspect(10px 20px 30px); // unquote("10px 20px 30px") @debug meta.inspect(("width": 200px)); // unquote('("width": 200px)') @debug meta.inspect(null); // unquote("null") @debug meta.inspect("Helvetica"); // unquote('"Helvetica"') === @debug meta.inspect(10px 20px 30px) // unquote("10px 20px 30px") @debug meta.inspect(("width": 200px)) // unquote('("width": 200px)') @debug meta.inspect(null) // unquote("null") @debug meta.inspect("Helvetica") // unquote('"Helvetica"') {% endcodeExample %} {% endfunction %}

{% function 'meta.keywords($args)', 'keywords($args)', 'returns:map' %} Returns the keywords passed to a mixin or function that takes arbitrary arguments. The $args argument must be an argument list.

The keywords are returned as a map from argument names as unquoted strings (not including $) to the values of those arguments.

{% render 'code_snippets/example-mixin-arbitrary-keyword-arguments' %} {% endfunction %}

{% function 'meta.mixin-exists($name, $module: null)', 'mixin-exists($name, $module: null)', 'returns:boolean' %} Returns whether a mixin named $name exists.

If $module is null, this returns whether a mixin named $name without a namespace exists. Otherwise, $module must be a string matching the namespace of a @use rule in the current file, in which case this returns whether that module has a mixin named $name.

{% codeExample 'mixin-exists', false %} @debug meta.mixin-exists("shadow-none"); // false

@mixin shadow-none {
  box-shadow: none;
}

@debug meta.mixin-exists("shadow-none"); // true
===
@debug meta.mixin-exists("shadow-none")  // false

@mixin shadow-none
  box-shadow: none


@debug meta.mixin-exists("shadow-none")  // true

{% endcodeExample %} {% endfunction %}

{% function 'meta.module-functions($module)', 'returns:map' %} {% render 'doc_snippets/module-system-function-status' %}

Returns all the functions defined in a module, as a map from function names to function values.

The $module parameter must be a string matching the namespace of a @use rule in the current file.

{% codeExample 'module-functions', false %} // functions.scss @function pow($base, $exponent) { $result: 1; @for $ from 1 through $exponent { $result: $result * $base; } @return $result; } --- @use "sass:map"; @use "sass:meta";

@use "functions";

@debug meta.module-functions("functions"); // ("pow": get-function("pow"))

@debug meta.call(map.get(meta.module-functions("functions"), "pow"), 3, 4); // 81
===
// _functions.sass
@function pow($base, $exponent)
  $result: 1
  @for $_ from 1 through $exponent
    $result: $result * $base

  @return $result
---
@use "sass:map"
@use "sass:meta"

@use "functions"

@debug meta.module-functions("functions") // ("pow": get-function("pow"))

@debug meta.call(map.get(meta.module-functions("functions"), "pow"), 3, 4) // 81

{% endcodeExample %} {% endfunction %}

{% function 'meta.module-variables($module)', 'returns:map' %} {% render 'doc_snippets/module-system-function-status' %}

Returns all the variables defined in a module, as a map from variable names (without $) to the values of those variables.

The $module parameter must be a string matching the namespace of a @use rule in the current file.

{% codeExample 'module-variables', false %} // _variables.scss $hopbush: #c69; $midnight-blue: #036; $wafer: #e1d7d2; --- @use "sass:meta";

@use "variables";

@debug meta.module-variables("variables");
// (
//   "hopbush": #c69,
//   "midnight-blue": #036,
//   "wafer": #e1d7d2
// )
===
// _variables.sass
$hopbush: #c69
$midnight-blue: #036
$wafer: #e1d7d2
---
@use "sass:meta"

@use "variables"

@debug meta.module-variables("variables")
// (
//   "hopbush": #c69,
//   "midnight-blue": #036,
//   "wafer": #e1d7d2
// )

{% endcodeExample %} {% endfunction %}

{% function 'meta.type-of($value)', 'type-of($value)', 'returns:unquoted string' %} Returns the type of $value.

This can return the following values:

New possible values may be added in the future. It may return either list or map for (), depending on whether or not it was returned by a map function.

{% codeExample 'type-of', false %} @debug meta.type-of(10px); // number @debug meta.type-of(10px 20px 30px); // list @debug meta.type-of(()); // list === @debug meta.type-of(10px) // number @debug meta.type-of(10px 20px 30px) // list @debug meta.type-of(()) // list {% endcodeExample %} {% endfunction %}

{% function 'meta.variable-exists($name)', 'variable-exists($name)', 'returns:boolean' %} Returns whether a variable named $name (without the $) exists in the current scope.

{% codeExample 'variable-exists', false %} @debug meta.variable-exists("var1"); // false

$var1: value;
@debug meta.variable-exists("var1"); // true

h1 {
  // $var2 is local.
  $var2: value;
  @debug meta.variable-exists("var2"); // true
}
===
@debug meta.variable-exists("var1")  // false

$var1: value
@debug meta.variable-exists("var1")  // true

h1
  // $var2 is local.
  $var2: value
  @debug meta.variable-exists("var2")  // true

{% endcodeExample %} {% endfunction %}

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Mixins

Functions

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