Style Dictionary Adapter

Style Dictionary consumes Variable Contract (DTCG) format and generates platform outputs like CSS variables, TypeScript types, and Tailwind CSS v4 custom properties.

Role

Style Dictionary is an output adapter. It reads Variable Contract JSON and produces files for consumption in code.

DTCG format support

Style Dictionary supports DTCG format natively. Use Variable Contract JSON files directly as Style Dictionary source files.

Configuration

Example Style Dictionary configuration:

{
  "source": ["tokens/**/*.json"],
  "platforms": {
    "css": {
      "transformGroup": "css",
      "buildPath": "dist/",
      "files": [
        {
          "destination": "variables.css",
          "format": "css/variables"
        }
      ]
    },
    "typescript": {
      "transformGroup": "js",
      "buildPath": "dist/",
      "files": [
        {
          "destination": "tokens.ts",
          "format": "typescript/es6-declarations"
        }
      ]
    }
  }
}

Output formats

Style Dictionary can generate:

  • CSS variables (css/variables)
  • SCSS variables (scss/variables)
  • Less variables (less/variables)
  • JavaScript/TypeScript (javascript/es6, typescript/es6-declarations)
  • JSON (json/nested, json/flat)
  • Tailwind CSS v4 (css/variables for @theme directive)
  • Android resources (android/resources)
  • iOS plist (ios/plist)
  • And more

Format differences

Style Dictionary has its own format (legacy), but supports DTCG format:

Legacy Style Dictionary format:

{
  "color": {
    "primary": {
      "value": "#0066cc",
      "type": "color"
    }
  }
}

DTCG format (Variable Contract):

{
  "color": {
    "primary": {
      "$type": "color",
      "$value": "#0066cc"
    }
  }
}

Style Dictionary handles both formats. Use DTCG format for Variable Contract compliance.

Transform groups

Transform groups apply multiple transforms:

  • css - CSS variable transforms
  • js - JavaScript/TypeScript transforms
  • scss - SCSS variable transforms
  • android - Android resource transforms
  • ios - iOS plist transforms

Custom transforms

You can create custom transforms for:

  • Naming conventions (camelCase, kebab-case, etc.)
  • Value transformations (unit conversion, color format)
  • Filtering (exclude certain variables)

Example custom transform:

module.exports = {
  name: 'name/kebab',
  type: 'name',
  transform: function(prop, options) {
    return prop.path.join('-');
  }
};

Reference resolution

Style Dictionary resolves references automatically. Variables that reference other variables are resolved to their final values in output files.

Example input:

{
  "color": {
    "primary": {
      "$type": "color",
      "$value": "#0066cc"
    },
    "text": {
      "primary": {
        "$type": "color",
        "$value": "{color.primary}"
      }
    }
  }
}

CSS output:

:root {
  --color-primary: #0066cc;
  --color-text-primary: #0066cc;
}

Mode handling

Style Dictionary can generate separate files for each mode or combine modes into a single file with mode selectors.

Example with modes:

{
  "color": {
    "surface": {
      "$type": "color",
      "$value": {
        "light": "#ffffff",
        "dark": "#000000"
      }
    }
  }
}

CSS output (separate files):

variables-light.css:

:root {
  --color-surface: #ffffff;
}

variables-dark.css:

:root {
  --color-surface: #000000;
}

Build workflow

Typical workflow:

  1. Store Variable Contract JSON in tokens/ directory
  2. Configure Style Dictionary to read from tokens/
  3. Run Style Dictionary build
  4. Generated files appear in dist/
  5. Import generated files in your code

Failure modes

If Style Dictionary configuration is wrong:

  • Missing source files cause empty outputs
  • Invalid transforms break value conversion
  • Reference resolution failures cause undefined values
  • Mode handling errors produce incorrect outputs

Validation

Style Dictionary validates:

  • JSON syntax
  • Reference resolution
  • Type correctness (for transforms that check types)

Variable Contract validation should happen before Style Dictionary build (in CI or pre-commit hooks).

Examples

Basic CSS variables

Input (tokens/color.json):

{
  "color": {
    "primary": {
      "$type": "color",
      "$value": "#0066cc"
    }
  }
}

Output (dist/variables.css):

:root {
  --color-primary: #0066cc;
}

TypeScript types

Input (same as above)

Output (dist/tokens.ts):

export const color = {
  primary: '#0066cc'
};

Tailwind CSS v4

Input (same as above)

Output (dist/theme.css):

@import "tailwindcss";

@theme {
  --color-primary: #0066cc;
}

Note: Tailwind CSS v4 uses CSS-first configuration. Generate CSS custom properties, not JavaScript config files. See Tailwind Adapter for details.

Out of scope

  • Style Dictionary installation and setup (see Style Dictionary docs)
  • Custom transform implementation details
  • Platform-specific build configurations
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