Ensuring Interconnected Design Tokens with Style Dictionary

Mastering the Art of Interconnected Design Tokens

When working with design systems, achieving a seamless connection between design tokens is crucial for consistency across platforms. 🧩 But what happens when your tokens lose their hierarchy during compilation? This is a challenge many developers face.

Imagine structuring your design tokens meticulously into three levels—primitive, semantic, and specific—only to find that after processing with Style Dictionary, they lose their interdependence. The result? Your semantic and specific tokens end up with primitive values, breaking the intended hierarchy.

In my own experience, I encountered this very issue while preparing design tokens for multiple operating systems. I needed a solution that retained the interconnected structure of my JSON files while ensuring the output was optimized for implementation. 🚀

In this guide, I'll walk you through how to configure Style Dictionary to maintain these relationships, ensuring that your tokens stay as interconnected as intended. Whether you're new to design tokens or troubleshooting a similar problem, these insights will be invaluable. Let’s dive in! 😊

Mastering Hierarchical Design Token Export

In the scripts provided, the primary goal is to maintain the hierarchical structure of design tokens across multiple levels—primitive, semantic, and specific. Using Style Dictionary, we introduce custom transformations and formats to ensure that relationships between tokens are preserved during the export process. For example, the `registerTransform` method customizes how token names are generated, using a structured format based on their category, type, and item attributes. This hierarchical naming ensures clarity and consistency across token compilations. 🛠️

Another key feature is the `registerFormat` method, which enables the export of tokens into a structured JSON file. This format retains the token relationships as defined in the original input, making it easier to implement them in various platforms. Imagine working on a large project where semantic tokens like "primary color" reference primitive tokens like "blue-500"—preserving this relationship during compilation is essential to prevent implementation errors. By leveraging these features, Style Dictionary becomes a powerful tool for maintaining token integrity.

In the Python-based script, we employ a recursive function to navigate through nested dictionaries, preserving the hierarchy during the transformation of design tokens. For instance, if a "button.primary.background" token references a "color.primary" token, the function ensures these relationships remain intact. This method is particularly useful for teams that need to work with design tokens outside the JavaScript ecosystem, as Python offers great flexibility for processing JSON files. 🚀

Finally, the integration of unit tests using Chai in the JavaScript script adds a critical layer of verification. These tests ensure that tokens not only compile correctly but also retain their intended relationships. For example, one test verifies that semantic tokens reference primitive values as expected, while another ensures that all three levels—primitive, semantic, and specific—are present in the compiled output. With these scripts and practices, design systems can scale efficiently while maintaining consistency across platforms, avoiding potential pitfalls and saving development time. 😊

// Import the Style Dictionary package
const StyleDictionary = require('style-dictionary');

// Define the custom transform to maintain token hierarchy
StyleDictionary.registerTransform({
  name: 'custom/name-hierarchy',
  type: 'name',
  transformer: (token) => {
    return [token.attributes.category, token.attributes.type, token.attributes.item]
      .filter(Boolean)
      .join('.');
  }
});

// Define the custom format for interconnected design tokens
StyleDictionary.registerFormat({
  name: 'custom/json-structured',
  formatter: ({ dictionary }) => {
    return JSON.stringify(dictionary.tokens, null, 2);
  }
});

// Configure Style Dictionary with your custom settings
const StyleDictionaryConfig = {
  source: ['tokens//*.json'],
  platforms: {
    web: {
      transformGroup: 'custom/name-hierarchy',
      buildPath: 'build/web/',
      files: [{
        destination: 'tokens.json',
        format: 'custom/json-structured'
      }]
    }
  }
};

// Extend and build the Style Dictionary
const SD = StyleDictionary.extend(StyleDictionaryConfig);
SD.buildAllPlatforms();

import json

# Load design tokens from a JSON file
with open('tokens.json', 'r') as file:
    tokens = json.load(file)

# Function to recursively maintain hierarchy
def maintain_hierarchy(data):
    structured_tokens = {}
    for key, value in data.items():
        if isinstance(value, dict):
            structured_tokens[key] = maintain_hierarchy(value)
        else:
            structured_tokens[key] = value
    return structured_tokens

# Process tokens to maintain hierarchy
structured_tokens = maintain_hierarchy(tokens)

# Export processed tokens to a new JSON file
with open('structured_tokens.json', 'w') as file:
    json.dump(structured_tokens, file, indent=2)

const fs = require('fs');
const { expect } = require('chai');

// Load the compiled tokens
const tokens = JSON.parse(fs.readFileSync('build/web/tokens.json', 'utf-8'));

describe('Design Token Compilation', () => {
  it('should preserve the hierarchy in tokens', () => {
    expect(tokens.semantic).to.have.property('primary');
    expect(tokens.semantic.primary).to.equal(tokens.primitive.colorBlue);
  });

  it('should include all levels of tokens', () => {
    expect(tokens).to.have.property('primitive');
    expect(tokens).to.have.property('semantic');
    expect(tokens).to.have.property('specific');
  });
});

Preserving Token Relationships Across Platforms

One overlooked aspect of working with design tokens is ensuring their compatibility with various platforms, such as web, iOS, and Android. While tools like Style Dictionary are powerful, they require careful configuration to ensure that tokens retain their intended structure. For example, semantic tokens like "button.primary" should reference primitive tokens like "color.blue" rather than hardcoding their values. This interconnectedness allows developers to make changes at the primitive level and see updates reflected across all dependent tokens. 🌐

To achieve platform-specific compatibility, custom transformations and formats can be tailored for each output. This ensures that the tokens are not only consistent but also optimized for the platform's native style conventions. For instance, iOS might require tokens in a `.plist` format, while web developers prefer JSON or CSS variables. Using these specialized outputs maintains token integrity while streamlining implementation for diverse teams. By focusing on these aspects, teams can create scalable, platform-agnostic design systems. 🚀

Another key consideration is integrating version control and collaborative workflows. By storing token files in a version-controlled repository and combining them with CI/CD pipelines, updates to tokens can be tested and deployed automatically. This ensures that tokens remain up-to-date across platforms without manual intervention, minimizing errors and maintaining the integrity of the design system. Such automation not only saves time but also supports growing teams handling complex token hierarchies. 😊