@theemel/editor

Interactive design system editor for React apps. Pick colors, generate harmony palettes, enforce WCAG AA contrast, customize typography and interaction states, and export CSS custom properties — all in real time. Fully responsive — works on desktop, tablet, and mobile.

Early Access: All features are currently unlocked for free — no license key or account required.

Install

npm install @theemel/editor

Peer Dependencies

Install optional peers for full functionality:

npm install axe-core lucide-react

Quick Start

import { DesignSystemEditor } from '@theemel/editor';
import '@theemel/editor/style.css';

function App() {
  return <DesignSystemEditor />;
}

The editor writes CSS custom properties (HSL values) to :root, so it works with any framework that consumes CSS variables.

Props

Premium Features

The following features require a valid license key:

License Key Format

Keys follow the format THEEMEL-XXXX-XXXX-XXXX with a checksum-validated third segment. Use generateLicenseKey() to create valid keys.

PremiumGate Component

Wrap any feature in PremiumGate to gate it behind a license key. Clicking a gated feature opens a modal with upgrade and sign-in options:

import { PremiumGate } from '@theemel/editor';

<PremiumGate feature="harmony-schemes" upgradeUrl="/pricing" signInUrl="/sign-in">
  <HarmonyControls />
</PremiumGate>

LicenseProvider

If using PremiumGate or useLicense outside of DesignSystemEditor, wrap your tree in LicenseProvider:

import { LicenseProvider } from '@theemel/editor';

<LicenseProvider licenseKey="THEEMEL-XXXX-XXXX-XXXX">
  <App />
</LicenseProvider>

Usage Examples

Basic — color picker only

<DesignSystemEditor accessibilityAudit={false} />

With PR creation

<DesignSystemEditor prEndpointUrl="/api/create-design-pr" />

With premium features

<DesignSystemEditor
  licenseKey="THEEMEL-XXXX-XXXX-XXXX"
  upgradeUrl="/pricing"
  signInUrl="/sign-in"
/>

With custom header content

<DesignSystemEditor
  headerRight={<button onClick={handleSignIn}>Sign In</button>}
  aboutUrl="/about"
/>

Listen for changes

<DesignSystemEditor
  onChange={(colors) => {
    console.log('Brand color:', colors['--brand']);
  }}
/>

Custom export handler

<DesignSystemEditor
  onExport={(css) => {
    navigator.clipboard.writeText(css);
  }}
/>

Embedded / headless

<DesignSystemEditor
  showHeader={false}
  showNavLinks={false}
/>

Exported Utilities

import {
  // Color utilities
  hslStringToHex,    // "210 50% 40%" -> "#336699"
  hexToHslString,    // "#336699" -> "210.0 50.0% 40.0%"
  contrastRatio,     // WCAG contrast ratio between two HSL strings
  fgForBg,           // Best foreground (black/white) for a background HSL
  EDITABLE_VARS,     // Array of { key, label } token definitions
  HARMONY_SCHEMES,   // ['Complementary', 'Analogous', 'Triadic', 'Split-Complementary']
  applyStoredThemeColors, // Restore persisted theme from localStorage

  // localStorage key constants
  CARD_STYLE_KEY,            // Key for card style storage
  TYPOGRAPHY_KEY,            // Key for typography storage
  ALERT_STYLE_KEY,           // Key for dialog alert style storage
  TOAST_STYLE_KEY,           // Key for toast style storage
  INTERACTION_STYLE_KEY,     // Key for interaction style storage

  // Card, typography & interaction style utilities
  applyStoredCardStyle,           // Restore card style from localStorage
  applyStoredTypography,          // Restore typography from localStorage
  applyStoredAlertStyle,          // Restore dialog alert style from localStorage
  applyStoredToastStyle,          // Restore toast style from localStorage
  applyStoredInteractionStyle,    // Restore button interaction style from localStorage

  // Shareable URL utilities
  serializeThemeState,            // Encode full theme state as base64 string
  deserializeThemeState,          // Decode base64 string back to theme state

  // Export utilities
  generateDesignTokens,           // Generate W3C Design Token JSON from theme state
  exportPaletteAsText,            // Export palette as HEX, RGB, or RGBA text
  exportPaletteAsSvg,             // Export palette as SVG string
  exportPaletteAsPng,             // Export palette as PNG Blob

  // Custom font utilities
  getCustomFonts,       // Load custom fonts from localStorage
  addCustomFont,        // Validate & add a Google Font by name
  removeCustomFont,     // Remove a custom font by label
  initCustomFonts,      // Re-register all custom fonts on startup

  // License utilities
  validateLicenseKey,   // Validate a THEEMEL-XXXX-XXXX-XXXX key
  generateLicenseKey,   // Generate a valid license key

  // Premium components & hooks
  LicenseProvider,      // Context provider for license state
  useLicense,           // Hook: { isValid, isPremium }
  PremiumGate,          // Gate component for premium features
} from '@theemel/editor';

Exported Types

import type {
  DesignSystemEditorProps,
  TokenDefinition,
  HarmonyScheme,
  CardStyleState,
  TypographyState,
  AlertStyleState,
  ToastStyleState,
  InteractionStyleState,
  TypoInteractionStyleState,
  CustomFontEntry,
  PremiumFeature,
  LicenseValidation,
  LicenseProviderProps,
  PremiumGateProps,
} from '@theemel/editor';

How It Works

1. Color picking — Click any swatch to open the native color picker. Changing a key color (brand, secondary, accent, background) automatically derives related tokens.
2. Harmony schemes (Pro) — Generate palettes using complementary, analogous, triadic, or split-complementary color relationships.
3. Contrast enforcement — Every foreground/background pair is checked against WCAG AA (4.5:1). Failing pairs are auto-corrected by adjusting lightness.
4. Typography — Choose heading and body fonts (including custom Google Fonts), adjust sizes, weights, line height, and letter spacing with live preview. Five built-in presets (System, Modern, Classic, Compact, Editorial).
5. Button interactions (Pro) — Fine-tune hover opacity, hover/active scale, transition duration, and focus ring width with presets (Subtle, Elevated, Bold).
6. Typography interactions (Pro) — Customize link hover/active behavior (opacity, scale, underline) and heading hover effects with live preview.
7. Persistence — All settings (colors, typography, card styles, dialog styles, toast styles, interactions) are saved to localStorage and restored on reload.
8. Per-section export — Every section header includes a CSS | Tokens split button to export CSS custom properties with Tailwind config, or W3C Design Token JSON, for that section.
9. Shareable URLs — Encode your full theme state in the URL hash and share it with anyone via a single link.
10. Palette export (Pro) — Download your palette as SVG or PNG, or copy as a HEX/RGB/RGBA text list.
11. Custom fonts (Pro) — Add any Google Font by name. The editor validates the font exists, loads all weights, adds it to heading/body dropdowns, and persists it across sessions.
12. Mobile friendly — Fully responsive UI with mobile-optimized dropdowns, compact swatch labels, and stacked layouts for smaller screens.

Package Architecture

The editor is built with Vite in library mode and published as an ES module:

@theemel/editor
├── dist/index.js      # ESM bundle (all components + utilities)
├── dist/index.d.ts    # TypeScript declarations
└── dist/style.css     # Pre-compiled, scoped Tailwind styles

Exports Map

{
  ".":            { "import": "./dist/index.js", "types": "./dist/index.d.ts" },
  "./style.css":  "./dist/style.css"
}

Import the main entry point for components and utilities, and style.css separately for styles. This keeps CSS opt-in and avoids side effects during tree-shaking.

Tailwind Scoping

The editor ships pre-compiled CSS via @theemel/editor/style.css. Styles are scoped using Tailwind's important: '.ds-editor' so they don't conflict with your app's styles. The root element is automatically wrapped in <div className="ds-editor">.

Development

# From the repo root
npm install

# Build the package
cd packages/editor
npm run build

# Watch mode
npm run dev

Testing

The project includes automated accessibility testing:

# Run all tests (includes axe-core a11y checks)
npm run test:run

# Lint for accessibility issues
npm run lint

The test suite uses vitest-axe to run axe-core against rendered components, catching WCAG violations automatically. ESLint with eslint-plugin-jsx-a11y provides static analysis for common accessibility anti-patterns.

Publishing to npm

The package is published as @theemel/editor on npm. To publish a new version:

# 1. Build
cd packages/editor
npm run build

# 2. Verify the tarball contents (should only include dist/)
npm pack --dry-run

# 3. Bump the version
npm version patch   # or minor / major

# 4. Publish (scoped packages require --access public on first publish)
npm publish --access public

You must be logged in to npm (npm login) with publish access to the @theemel scope.

License

MIT