meta.accepts-content($mixin) returns a boolean: whether the given mixin value can accept a @content block. Official docs: it returns true if accepting content is possible, even when the mixin does not always use @content. Load it with @use "sass:meta" on Dart Sass 1.69+.
Pass a mixin value from meta.get-mixin() or meta.module-mixins()—not a plain string name.
Use this before meta.apply() when a helper sometimes forwards @content and sometimes does not.
accepts-content asks “can this mixin take content?” meta.content-exists() asks “did the current include pass content?”
@use "sass:meta";
meta.accepts-content($mixin); //=> boolean
@mixin plain($n) { width: $n; }
@mixin wrap { @content; }
meta.accepts-content(meta.get-mixin("plain")); // false
meta.accepts-content(meta.get-mixin("wrap")); // true
// Module API — prefer meta.accepts-content after @use "sass:meta"Pattern: get a mixin value → check accepts-content → branch before meta.apply with or without a content block.
Two related helpers, different questions:
| Helper | Asks | Where |
|---|---|---|
meta.accepts-content($mixin) | Can this mixin value take @content? | Anywhere you have a mixin value |
meta.content-exists() | Did this include pass a content block? | Only inside a mixin |
true from accepts-content | Content is possible (even if conditional) | Not “always uses @content” |
false | No @content slot | Do not forward a content block |
@content.A mixin that only calls @content inside @if still returns true—accepting content is possible.
Examples target Dart Sass 1.69+ with @use "sass:meta". Open View Compiled CSS for verified output.
@contentA plain mixin returns false.
@use "sass:meta";
@mixin box($padding) {
padding: $padding;
}
.basic {
--accepts: #{meta.accepts-content(meta.get-mixin("box"))};
}box has no @content.get-mixin returns a mixin value.accepts-content is false.@contentA wrapper that includes @content returns true.
@use "sass:meta";
@mixin media($query) {
@media #{$query} {
@content;
}
}
.true-case {
--accepts: #{meta.accepts-content(meta.get-mixin("media"))};
}media declares @content.true.meta.apply.@content Still CountsOfficial idea: true if content is possible, even when not always used.
@use "sass:meta";
@mixin maybe($flag) {
@if $flag {
@content;
}
}
.conditional {
--accepts: #{meta.accepts-content(meta.get-mixin("maybe"))};
}@content sits behind @if.true.meta.applyForward a content block only when the target mixin accepts one.
@use "sass:meta";
@mixin plain {
color: blue;
}
@mixin with-content {
.inner {
@content;
}
}
@mixin apply-if-content($mixin) {
@if meta.accepts-content($mixin) {
@include meta.apply($mixin) {
outline: 1px solid red;
}
} @else {
@include meta.apply($mixin);
}
}
.a {
@include apply-if-content(meta.get-mixin("plain"));
}
.b {
@include apply-if-content(meta.get-mixin("with-content"));
}accepts-content first.plain gets apply without content.with-content receives the outline block.meta.content-existsCapability vs whether content was passed on this include.
@use "sass:meta";
@mixin wrap {
--can: #{meta.accepts-content(meta.get-mixin("wrap"))};
--passed: #{meta.content-exists()};
@content;
}
.no-block {
@include wrap;
}
.with-block {
@include wrap {
color: green;
}
}--can stays true for both includes.--passed depends on the caller.Most mistakes are passing a string name or confusing capability with “content was passed.”
Use meta.get-mixin("name"). A bare string is not a mixin value.
true ≠ always uses contentConditional @content still reports true. Capability is not a runtime guarantee.
Inside a mixin, use meta.content-exists().
Older compilers and LibSass / Ruby Sass do not provide this API.
Prefer the module form with Dart Sass 1.69+.
| API | Status |
|---|---|
meta.accepts-content() | Dart Sass 1.69+ via @use "sass:meta" |
| Argument | Mixin value (e.g. from meta.get-mixin) |
| Return type | Boolean |
| LibSass / Ruby Sass | Not available |
Compile with the Dart Sass CLI.
@content.get-mixin / module maps.meta.apply before forwarding content.@use "sass:meta".One line: when you need to know if a mixin value can take @content before applying it, call meta.accepts-content($mixin).
Practical checklist:
1. @use "sass:meta"
2. Get a mixin value (meta.get-mixin / module-mixins)
3. Call meta.accepts-content($mixin)
4. Branch before meta.apply with or without @content
5. Use content-exists() inside mixins for "was content passed?"Include a mixin value and optionally forward @content.
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