@spelech/vite-plugin-theme-editor

Live in-browser CSS variable (:root) theme editor with instant visual feedback and AST-preserving disk sync for Vite projects.

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Features

• ⚡ Zero-Latency Live Preview: Mutates document.documentElement.style instantly for sub-millisecond visual updates as you adjust sliders and color pickers.
• 🎨 Smart Variable Controls: Auto-detects CSS variable types:
  • Colors: Dual color swatch preview + native color picker + HEX/RGBA text inputs.
  • Dimensions / Radii / Spacing: Adaptive range sliders + numeric inputs with CSS unit selectors (px, rem, em, %, etc.).
  • Fonts & Typography: Font family text inputs with live preview samples.
  • Raw / Fallback: Safe text editing for complex CSS functions, shadows, or gradients.
• 🛡️ Zero Styling Pollution (Shadow DOM): The entire editor UI lives inside an encapsulated Web Component (<theme-editor-overlay>). No host CSS leaks in, and editor styles never alter your application.
• 📝 AST-Preserving Disk Sync: Uses PostCSS to update CSS variables directly in source files on disk while preserving all comments, indentation, formatting, and empty lines.
• 🔍 Interactive Diff Preview: Previews syntax-highlighted line-by-line additions and deletions before saving changes to disk.
• 🚀 Dev Mode Only: Injected only during vite dev (apply: 'serve'). 0KB production bundle overhead.
• ⌨️ Keyboard Shortcut: Press Alt + T (or Option + T on macOS) to quickly toggle the editor drawer.

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Installation

npm install -D @spelech/vite-plugin-theme-editor

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Usage

Add the plugin to your vite.config.ts or vite.config.js:

import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';
import { themeEditorPlugin } from '@spelech/vite-plugin-theme-editor';

export default defineConfig({
  plugins: [
    react(),
    themeEditorPlugin()
  ]
});

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Options

interface ThemeEditorOptions {
  /**
   * Glob patterns for stylesheets to scan for CSS custom properties.
   * Default: ['src/**/*.{css,scss,pcss,postcss,less}', '*.{css,scss}']
   */
  include?: string[];

  /**
   * Glob patterns to ignore.
   * Default: ['**/node_modules/**', '**/dist/**', '**/.git/**', '**/coverage/**']
   */
  exclude?: string[];

  /**
   * Open the editor drawer by default on page load.
   * Default: false
   */
  defaultOpen?: boolean;
}

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License

MIT © spelech