EmbeddedSass.Net.Compiler 1.0.0

EmbeddedSass.Net is an asynchronous, thread-safe .NET host for the Embedded Sass Protocol.

The library runs a trusted Embedded Dart Sass executable supplied by the application or by the optional compiler package.

using EmbeddedSass.Net;
using EmbeddedSass.Net.Compiler;

await using var compiler = new SassCompiler(new SassCompilerOptions
{
    CompilerPath = "/absolute/path/to/dart-sass"
});

var result = await compiler.CompileStringAsync("$color: red; a { color: $color; }");
Console.WriteLine(result.Css);

The optional compiler package contains the x64 and ARM64 builds for Windows, macOS, and Linux, removing the need to manage an external executable:

using EmbeddedSass.Net;
using EmbeddedSass.Net.Compilation;
using EmbeddedSass.Net.Compiler;

var options = new SassCompilerOptions().UseBundledDartSass();
await using var compiler = new SassCompiler(options);

Imports

Filesystem imports can be resolved from one or more load paths:

var result = await compiler.CompileAsync(
    new SassCompileRequest(new SassStringInput("@use 'theme';"))
    {
        LoadPaths = ["/absolute/path/to/styles"]
    });

MSBuild integration

EmbeddedSass.Net.MsBuild compiles Sass before ASP.NET Core resolves static web assets. The package includes the Sass compiler, so a Sass installation is not required.

Add the package to the project:

<PackageReference Include="EmbeddedSass.Net.MsBuild" Version="1.0.0" />

Default behavior

When the project contains a Sass directory, the package:

• Compiles every .scss and .sass file that does not begin with _.
• Writes generated CSS to wwwroot/css.
• Preserves relative directory paths.
• Treats underscore-prefixed files as Sass partials.
• Produces expanded CSS and external source maps in Debug builds.
• Embeds source content in Debug source maps.
• Produces compressed CSS without source maps in other configurations.

Explicit inputs

Add EmbeddedSass items to override the default Sass-to-wwwroot/css mapping.

<ItemGroup>
  <EmbeddedSass Include="Client/Styles">
    <OutputPath>wwwroot/assets/css</OutputPath>
    <LoadPaths>Client/Shared;vendor/styles</LoadPaths>
  </EmbeddedSass>

  <EmbeddedSass Include="Admin/admin.scss">
    <OutputPath>wwwroot/admin.css</OutputPath>
  </EmbeddedSass>
</ItemGroup>

For a directory item, OutputPath is the destination directory. Relative source directories are preserved.

For a file item, OutputPath is the exact generated CSS file path.

Explicit items can reference multiple source directories or individual entry files.

Item metadata

Project properties

<PropertyGroup>
  <EmbeddedSassEnabled>true</EmbeddedSassEnabled>
  <EmbeddedSassOutputStyle>Auto</EmbeddedSassOutputStyle>
  <EmbeddedSassGenerateSourceMap>Auto</EmbeddedSassGenerateSourceMap>
  <EmbeddedSassIncludeSourcesInSourceMap>true</EmbeddedSassIncludeSourcesInSourceMap>
  <EmbeddedSassQuietDependencies>false</EmbeddedSassQuietDependencies>
  <EmbeddedSassSilencedDeprecations></EmbeddedSassSilencedDeprecations>
</PropertyGroup>

Generated CSS and source-map files are registered as project content, included during publish, and removed by the standard MSBuild clean process.

See the EmbeddedSass.Net.Sample.AspNetCore sample for a complete application.

AI Notice

AI tools were used as part of the development process and are disclosed here for transparency. The final code was reviewed, refactored and tested by a human (specifically me, @gumbarros ).