Sass meta.module-functions() Function

What You’ll Learn

meta.module-functions() belongs to the built-in sass:meta module. It returns every function in a @used module as a map of names to function values. This page covers the official pow + meta.call pattern, built-in modules like sass:math, and five compiled examples.

What Is meta.module-functions()?

Official docs: returns all the functions defined in a module, as a map from function names to function values. Think of it as opening a toolbox and seeing every tool labeled by name—ready to pick one with map.get and run it with meta.call.

• $module must be a string matching a @use namespace in the current file.
• Map keys are function names (strings). Map values are function values (not computed results).
• Works for your own modules and built-ins like sass:math after you @use them.
• Dart Sass 1.23+ only—LibSass and Ruby Sass do not support it.

📝 Syntax

@use "sass:meta";

// Dart Sass 1.23+ (no legacy global name)
meta.module-functions($module)

Parameters

Return value

📦 Loading sass:meta

@use "sass:map";
@use "sass:meta";
@use "functions";

$fns: meta.module-functions("functions");
$result: meta.call(map.get($fns, "pow"), 3, 4); // 81

There is no legacy global module-functions(). Always load sass:meta and call meta.module-functions.

⚙ The Official Call Pattern

Docs show listing a custom module, then picking one function and running it:

@use "sass:map";
@use "sass:meta";
@use "functions";

// Map of names → function values
@debug meta.module-functions("functions");
// ("pow": get-function("pow"), …)

// Pick "pow" and call it: 3^4 = 81
@debug meta.call(map.get(meta.module-functions("functions"), "pow"), 3, 4);

If you wrote @use "functions" as fn, pass "fn" as $module.

📋 Related Meta Helpers

🛠 Compatibility

This is about Sass compilers, not browsers. The map is built at compile time.

Prefer current Dart Sass. Only Dart Sass supports this function.

Examples Gallery

Each example uses meta.module-functions at compile time (Dart Sass 1.23+). Open View Compiled CSS for verified output.

@function pow($base, $exponent) {
  $result: 1;
  @for $_ from 1 through $exponent {
    $result: $result * $base;
  }
  @return $result;
}

@function double($n) {
  @return $n * 2;
}

@use "sass:map";
@use "sass:meta";
@use "functions";

$fns: meta.module-functions("functions");

.probe {
  --keys: #{meta.inspect(map.keys($fns))};
}

.probe {
  --keys: "pow", "double";
}

@use "sass:map";
@use "sass:meta";
@use "functions";

.result {
  width: meta.call(map.get(meta.module-functions("functions"), "pow"), 3, 4) * 1px;
}

.result {
  width: 81px;
}

@use "sass:map";
@use "sass:meta";
@use "sass:math";

$math-fns: meta.module-functions("math");

.probe {
  --has-div: #{map.has-key($math-fns, "div")};
  --has-pow: #{map.has-key($math-fns, "pow")};
  --has-nope: #{map.has-key($math-fns, "nope")};
}

.probe {
  --has-div: true;
  --has-pow: true;
  --has-nope: false;
}

@use "sass:list";
@use "sass:map";
@use "sass:meta";
@use "functions";

$fns: meta.module-functions("functions");

.count {
  --n: #{list.length(map.keys($fns))};
}

.count {
  --n: 2;
}

@use "sass:map";
@use "sass:meta";
@use "functions";

$fns: meta.module-functions("functions");
$name: "double";

.box {
  @if map.has-key($fns, $name) {
    width: meta.call(map.get($fns, $name), 24px);
  } @else {
    width: 24px;
  }
}

.box {
  width: 48px;
}

🚀 Real-World Use Cases

• Plugin registries — discover helpers a theme module exports, then call by name.
• Dynamic math paths — pick math.div / math.pow from the catalog.
• Documentation / debug peeks — print map.keys while building a design system.
• Safe optional APIs — map.has-key before meta.call.
• Module inventories — count or loop members for code generation at compile time.

⚠️ Common Pitfalls

• Wrong namespace string — must match this file’s @use … as name exactly.
• Module not loaded here — only @use rules in the current file count.
• Confusing values with results — map values are function references, not already-computed numbers.
• Calling without meta.call — you must run function values through meta.call.
• Expecting LibSass — this API is Dart Sass only (1.23+).

💡 Best Practices