Home Sass Meta meta.module-mixins() Definition
Definition and Usage meta.module-mixins($module) returns a map of every mixin defined in $module—keys are mixin names, values are mixin values . Include them with meta.apply1.69+ ). Load with @use "sass:meta".
Official sample idea. After @use "mixins", @include meta.apply(map.get(meta.module-mixins("mixins"), "stretch")) emits the stretch flex rules.
$module matches a namespace.Pass a string matching a @use namespace in the current file (e.g. "mixins"), or a module value.
Map values are not CSS. Include them with @include meta.apply($mixin). Peek at names with map.keys + meta.inspect
Syntax
Syntax @use "sass:map";
@use "sass:meta";
@use "mixins";
meta.module-mixins($module); //=> map
// Official pattern
.header {
@include meta.apply(
map.get(meta.module-mixins("mixins"), "stretch")
);
}
// Module API — Dart Sass 1.69+ (with meta.apply) Pattern: @use the module → module-mixins for the catalog → map.get / map.has-key → @include meta.apply.
Code
SCSS Examples Examples target Dart Sass 1.69+ with @use "sass:meta". Open View Compiled CSS for verified output (matches official Sass docs samples where shown).
1. Keys 2. apply + stretch 3. Probe 4. Optional 5. Guard Example 1 — List Mixin Names in a Module Inspect map.keys so you can see the catalog without printing mixin values.
@mixin stretch() {
align-items: stretch;
display: flex;
flex-direction: row;
}
@mixin soft-shadow {
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
} @use "sass:map";
@use "sass:meta";
@use "mixins";
$mx: meta.module-mixins("mixins");
.probe {
--keys: #{meta.inspect(map.keys($mx))};
} .probe {
--keys: "stretch", "soft-shadow";
} How It Works @use "mixins" loads the partial.module-mixins returns the map.map.keys lists the names.inspect peeks at them for learning / debug.Example 2 — Official map.get + meta.apply Pick stretch from the map and include it on .header.
@use "sass:map";
@use "sass:meta";
@use "mixins";
.header {
@include meta.apply(
map.get(meta.module-mixins("mixins"), "stretch")
);
} .header {
align-items: stretch;
display: flex;
flex-direction: row;
} How It Works map.get picks the stretch mixin value.meta.apply includes it into the selector.CSS emits the flex stretch rules.Matches the official Sass docs CSS output.Example 3 — Count and Probe Keys Combine list.length with map.has-key for a quick inventory.
@use "sass:list";
@use "sass:map";
@use "sass:meta";
@use "mixins";
$mx: meta.module-mixins("mixins");
.count {
--n: #{list.length(map.keys($mx))};
--has-stretch: #{map.has-key($mx, "stretch")};
--has-nope: #{map.has-key($mx, "nope")};
} .count {
--n: 2;
--has-stretch: true;
--has-nope: false;
} How It Works _mixins.scss exports two mixins.list.length counts the keys → 2.has-key finds stretch.Unknown names return false.Example 4 — Optional Mixin Include Include a helper only when the catalog contains it.
@use "sass:map";
@use "sass:meta";
@use "mixins";
$mx: meta.module-mixins("mixins");
.card {
@if map.has-key($mx, "soft-shadow") {
@include meta.apply(map.get($mx, "soft-shadow"));
}
padding: 1rem;
} .card {
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
padding: 1rem;
} How It Works has-key confirms soft-shadow.meta.apply includes it.padding always runs.Remove the mixin and the card still compiles with padding only.Example 5 — Guard Before meta.apply Check map.has-key so optional plugin names fail safely.
@use "sass:map";
@use "sass:meta";
@use "mixins";
$mx: meta.module-mixins("mixins");
$name: "stretch";
.row {
@if map.has-key($mx, $name) {
@include meta.apply(map.get($mx, $name));
} @else {
display: block;
}
} .row {
align-items: stretch;
display: flex;
flex-direction: row;
} How It Works $name is looked up in the catalog.True path applies the mixin value.Missing names take the @else fallback.Safer for plugin-style dynamic includes.Edge Cases & Pitfalls Most module-mixins bugs are wrong namespace strings or forgetting meta.apply.
namespace String must match @use After @use "mixins" as mx, pass "mx", not "mixins".
apply Map values need meta.apply You cannot @include a map entry directly—resolve with map.get, then apply.
guard Check before optional applies Use map.has-key (or mixin-existsmap.get + apply.
vs Functions use module-functions Dynamic functions return values via module-functionsmeta.call.
Toolchain
Sass Support Prefer the module form with Dart Sass 1.69+ (for meta.apply).
API Status meta.module-mixins()Dart Sass via @use "sass:meta" Return type Map (name → mixin value) Include with @include meta.apply($mixin) (1.69+)LibSass / Ruby Sass Not available
Compile with the Dart Sass CLI .
Remember
Key Takeaways Returns a map of every mixin in a loaded module.
Include with map.get + meta.apply (official pattern).
$module matches @use namespace in the current file.
Dart Sass 1.69+ for apply on mixin values.
One line: to list every mixin in a @use module, use meta.module-mixins($module).
Practice
Compile Notes Practical checklist:
1. @use "sass:meta" (+ "sass:map")
2. @use "your-module"
3. $mx: meta.module-mixins("your-module")
4. map.get / map.has-key / map.keys
5. @include meta.apply($mixin) to emit CSS Frequently Asked Questions What does Sass meta.module-mixins() do? meta.module-mixins($module) returns a map of every mixin defined in that @use module—keys are mixin names, values are mixin values you include with meta.apply.
What must $module be? A string matching the namespace of a @use rule in the current file—for example "mixins" after @use "mixins". It can also be a module value.
How do I include a mixin from the map? Official pattern: @include meta.apply(map.get(meta.module-mixins("mixins"), "stretch")). map.get picks the mixin value; meta.apply includes it.
How is it different from meta.mixin-exists? mixin-exists answers yes/no for one name. module-mixins returns the whole catalog of mixins in a module as a map.
How is it different from meta.get-mixin? get-mixin looks up one mixin by name. module-mixins returns all mixins in a module at once—handy for registries, loops, and map.has-key guards.
Which compilers support it? Dart Sass 1.69+ (needed for meta.apply on mixin values). LibSass and Ruby Sass do not. Prefer current Dart Sass.
About the author Developer, cloud engineer, and technical writer
I write practical tutorials so students and working developers can learn by doing—from databases and APIs to deployment on AWS.
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