ionic-framework/core/scripts/tokens.js

/* For generating Design Tokens, we use Style Dictionary for several reasons:
- It's prepared to easily generate tokens for multiple types of outputs (CSS, SCSS, iOS, Android, documentation, etc.).
- It also works very well out of the box with any kind of Design Tokens formats, like Figma Tokens, as well as APIs to adjust to more custom ones.
- It is probably the most well-known and widely used Design Tokens tool. It has also been regularly maintained for a long time.
- It can easily scale to different necessities we might have in the future.
*/
// eslint-disable-next-line @typescript-eslint/no-var-requires
const StyleDictionary = require('style-dictionary');

const { fileHeader } = StyleDictionary.formatHelpers;

// Empty for as an example of how we can add some extra variables, not from the tokens JSON
const customVariables = ``;

// Prefix for all generated variables
const variablesPrefix = 'ionic';

function hexToRgb(hex) {
  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return result
    ? {
        r: parseInt(result[1], 16),
        g: parseInt(result[2], 16),
        b: parseInt(result[3], 16),
      }
    : null;
}

// CSS vanilla :root format
StyleDictionary.registerFormat({
  name: 'rootFormat',
  formatter({ dictionary, file }) {
    // Add a prefix to all variable names
    const prefixedVariables = dictionary.allProperties.map((prop) => {
      const rgb = hexToRgb(prop.value);
      return `  --${variablesPrefix}-${prop.name}: ${prop.value};${
        rgb ? `\n  --${variablesPrefix}-${prop.name}-rgb: ${rgb.r}, ${rgb.g}, ${rgb.b};` : ``
      }`;
    });

    return (
      fileHeader({ file }) +
      ':root {\n' +
      prefixedVariables.join('\n') + // Join all prefixed variables with a newline
      customVariables +
      '\n}\n'
    );
  },
});

// scss variables format
StyleDictionary.registerFormat({
  name: 'scssVariablesFormat',
  formatter({ dictionary, file }) {
    // Add a prefix to all variable names
    const prefixedVariables = dictionary.allProperties.map((prop) => {
      const rgb = hexToRgb(prop.value);
      return `$${variablesPrefix}-${prop.name}: var(--${variablesPrefix}-${prop.name}, ${prop.value});${
        rgb
          ? `\n$${variablesPrefix}-${prop.name}-rgb: var(--${variablesPrefix}-${prop.name}-rgb, ${rgb.r}, ${rgb.g}, ${rgb.b});`
          : ``
      }`;
    });

    return (
      fileHeader({ file }) +
      prefixedVariables.join('\n') + // Join all prefixed variables with a newline
      customVariables +
      '\n'
    );
  },
});

// Create utility-classes
StyleDictionary.registerFormat({
  name: 'cssUtilityClassesFormat',
  formatter({ dictionary, file }) {
    const utilityClasses = dictionary.allProperties.map((prop) => {
      let tokenType = prop.attributes.category;
      const className = `${prop.name}`;
      let utilityClass = '';

      switch (tokenType) {
        case 'color':
          utilityClass = `.${variablesPrefix}-${className} {\n  color: $ionic-${prop.name};\n}
.${variablesPrefix}-background-${className} {\n  background-color: $ionic-${prop.name};\n}`;
          break;
        case 'border':
          const borderAttribute = prop.attributes.type === 'radius' ? 'border-radius' : 'border-width';
          utilityClass = `.${variablesPrefix}-${className} {\n  ${borderAttribute}: $ionic-${prop.name};\n}`;
          break;
        case 'font':
          let fontAttribute;
          switch (prop.attributes.type) {
            case 'size':
              fontAttribute = 'font-size';
              break;
            case 'weight':
              fontAttribute = 'font-weight';
              break;
            case 'line-height':
              fontAttribute = 'line-height';
              break;
            case 'letter-spacing':
              fontAttribute = 'letter-spacing';
              break;
            case 'family':
              return;
          }
          utilityClass = `.${variablesPrefix}-${className} {\n  ${fontAttribute}: $ionic-${prop.name};\n}`;
          break;
        case 'elevation':
          utilityClass = `.${variablesPrefix}-${className} {\n  box-shadow: $ionic-${prop.name};\n}`;
          break;
        case 'space':
          utilityClass = `.${variablesPrefix}-margin-${className} {\n  --margin-start: #{$ionic-${prop.name}};\n  --margin-end: #{$ionic-${prop.name}};\n  --margin-top: #{$ionic-${prop.name}};\n  --margin-bottom: #{$ionic-${prop.name}};\n\n  @include margin(${prop.value});\n};\n 
.${variablesPrefix}-padding-${className} {\n  --padding-start: #{$ionic-${prop.name}};\n  --padding-end: #{$ionic-${prop.name}};\n  --padding-top: #{$ionic-${prop.name}};\n  --padding-bottom: #{$ionic-${prop.name}};\n\n  @include padding(${prop.value});\n};\n`;
          break;
        default:
          utilityClass = `.${variablesPrefix}-${className} {\n  ${tokenType}: $ionic-${prop.name};\n}`;
      }

      return utilityClass;
    });

    return [
      fileHeader({ file }),
      '@import "./ionic.vars";\n@import "../themes/mixins";\n',
      utilityClasses.join('\n'),
    ].join('\n');
  },
});

// Make Style Dictionary comply with the $ format on properties from W3C Guidelines
const w3cTokenJsonParser = {
  pattern: /\.json|\.tokens\.json|\.tokens$/,
  parse({ contents }) {
    // replace $value with value so that style dictionary recognizes it
    var preparedContent = (contents || '{}')
      .replace(/"\$?value":/g, '"value":')
      // convert $description to comment
      .replace(/"\$?description":/g, '"comment":');
    //

    return JSON.parse(preparedContent);
  },
};

StyleDictionary.registerParser(w3cTokenJsonParser);

// Generate Tokens
StyleDictionary.extend({
  source: ['./src/foundations/*.json'],
  platforms: {
    css: {
      buildPath: './src/foundations/',
      transformGroup: 'css',
      files: [
        {
          destination: 'ionic.root.scss',
          format: 'rootFormat',
          options: {
            outputReferences: true,
            fileHeader: `myFileHeader`,
          },
        },
      ],
    },
    scss: {
      buildPath: './src/foundations/',
      transformGroup: 'scss',
      files: [
        {
          destination: 'ionic.vars.scss',
          format: 'scssVariablesFormat',
          options: {
            outputReferences: true,
            fileHeader: `myFileHeader`,
          },
        },
        {
          destination: 'ionic.utility.scss',
          format: 'cssUtilityClassesFormat',
          options: {
            outputReferences: true,
            fileHeader: `myFileHeader`,
          },
        },
      ],
    },
  },
  fileHeader: {
    myFileHeader: () => {
      return [`This is an auto-generated file, please do not change it directly.`, `Ionic Design System`];
    },
  },
}).buildAllPlatforms();