Otter Style Dictionary

This package is an Otter Framework Module.

Description

This package exposes a set of Hooks and Modules for the Style Dictionary to enhance the capabilities of Design Tokens.

Get Started

Set up your Style Dictionary in your project thanks to the command:

ng add @ama-styling/style-dictionary

By default, the command will do the following updates:

• Add a dev dependency to the Style Dictionary package.
• Create a minimal config.mjs configuration file with the required setup for CSS and Metadata generation.
• Add the generate:theme and generate:metadata scripts in the project package.json.

You will then be able to customize this setup with your project's specifications:

• Customize the Style Dictionary configuration in the generated config.mjs file.
• Add extensions to your source Design Token via the enhancement mechanism.
• Configure output files thanks to the getTargetFiles helper.

Enhancement

Design Token Extensions

The Design Tokens format allows to provide the $extensions property to enhance the Token it is applied to.
The property can be applied to the Token directly as follows:

// colors.token.json
{
  "colors": {
    "primary": {
      "$value": "#000000",
      "$extensions": {
        "o3rPrivate": true
      }
    }
  }
}

or in a dedicated .extensions.json file (when the ama/json-parser/extensions parser is loaded):

// color.token.json
{
  "colors": {
    "primary": {
      "$value": "#000000"
    }
  }
}

// custom.extensions.json
{
  "colors.primary": {
    "$description": "Primary private color",
    "$extensions": {
      "o3rPrivate": true
    }
  }
}

Available Otter Extensions

[!WARNING] The required hooks need to be registered to the Style Dictionary configuration to fully support the extension.

Modules

Parsers

Pre-processor

Transforms

Transform-groups

Formats

Registration process

The different hooks/modules can be registered individually via the different register...() functions from StyleDictionary or all at once with the register function as follows:

import { register, baseConfig } from '@ama-styling/style-dictionary';

const sd = new StyleDictionary({
  ...baseConfig,
  // custom configs ...
});

register(sd); // Register all Otter modules

[!IMPORTANT] To be able to use any of the listed modules/hooks, they have to be registered to the StyleDefinition instance.

[!TIP] The helper baseConfig will provide the minimal configuration for Otter extension support.

Helpers

To enhance and facilitate the configuration of the StyleDictionary instance, the @ama-styling/style-dictionary exposes a set of helpers.

getTargetFiles

The getTargetFiles function is used to parameterize the generated file based on Design Token (following the same logic as $extensions):

// Example to generate the `color-primary-**` variables in `my-color-primary.css`

import { getTargetFiles } from '@ama-styling/style-dictionary';

const rule = {
  'color.primary': 'my-color-primary.css'
};

// or `const rule = {color: {primary: 'my-color-primary.css'}}`
// or `const rule = {'color.primary': {$extensions: {o3rTargetFile: 'my-color-primary.css'}}}`
// or `const rule = {'color: {primary': {$extensions: {o3rTargetFile: 'my-color-primary.css'}}}}`

const sd = new StyleDictionary({
  //...
  plateforms: {
    css: {
      files: [
        ...getTargetFiles({ rule, { format: 'css', defaultFile: 'default-file.css' } })
      ]
    }
  }
});

register(sd); // Register all Otter modules

[!NOTE] The format option will be applied to all the files provided to the getTargetFiles function (including defaultFile). defaultFile defines the default file where variables not matching any rule will be generated.

The helper function getTargetFiles is registering the filter into StyleDictionary with a unique ID.
This IDs can be retrieved as follows:

import { getTargetFiles } from '@ama-styling/style-dictionary';

const sd = new StyleDictionary();
const files = getTargetFiles({ rules, { styleDictionary: sd } });

/**
 * Filter IDs registered in {@link sd} Style Dictionary instance
 * @type {string[]}
 **/
const filterIds = files.map(({ filter }) => filter);

Advanced

Basic Node Configuration Example

// style-builder.mjs

import { register, getTargetFiles, baseConfiguration } from '@ama-styling/style-dictionary';
import StyleDictionary from 'style-dictionary';

// Rules to generate different CSS files according to Token name
const fileRules = {
  colors: 'style/colors.tokens.css',
  'components.panel': 'components/panel/panel.tokens.css'
}

const sd = new StyleDictionary({
  ...baseConfiguration, // Use basic Otter configuration setup
  usesDtcg: true, // Use Design Token Standard format

  source: ['tokens/*.tokens.json'], // Design Token files
  include: ['token.extensions.json'], // Custom extensions

  platforms: {
    // Generate CSS Files
    css: {
      options: {
        outputReferences: true // to output `--var: var(--other-var)` instead of the value of `--other-var`
      },
      transformGroup: 'ama/css/recommended',
      files: [
        ...getTargetFiles(fileRules, { format: 'css' }),
        // default CSS file where generate variables
        { destination: 'style/default.tokens.css', format: 'css' }
      ]
    },
    cms: {
      options: {
        outputReferences: true
      },
      transformGroup: 'ama/css/recommended',
      files: [
        { destination: 'style.metadata.json', format: 'ama/json/metadata' }
      ]
    }
  }
});

// Register otter hooks/modules
register(sd);

if (process.env.CSS_ONLY){
  sd.buildPlatform('css');
} else {
  sd.buildAllPlatforms();
}

Can be run with the following command:

node ./style-builder.mjs