slideshare/VITE_PERFORMANCE.md

Vite Performance Standards

Missing Configuration

The current vite.config.ts is missing critical performance optimizations.

Required Vite Configuration Updates

1. Resolve Extensions (CRITICAL)

// ADD to vite.config.ts
export default defineConfig({
  resolve: {
    extensions: ['.js', '.ts', '.jsx', '.tsx', '.json']
  }
});

Impact: Faster module resolution, explicit extension requirements

2. Server Warmup (HIGH IMPACT)

// ADD to vite.config.ts
export default defineConfig({
  server: {
    warmup: {
      clientFiles: [
        './src/components/**/*.tsx',
        './src/utils/**/*.ts', 
        './src/types/**/*.ts',
        './src/themes/**/*.ts'
      ]
    }
  }
});

Impact: Faster initial load times, better dev experience

3. Build Optimizations

// ADD to vite.config.ts
export default defineConfig({
  build: {
    rollupOptions: {
      output: {
        manualChunks: {
          vendor: ['react', 'react-dom'],
          router: ['react-router-dom'],
          themes: ['./src/utils/themeLoader', './src/utils/cssParser']
        }
      }
    }
  }
});

Impact: Better code splitting, improved cache utilization

4. Dependency Pre-bundling

// ADD to vite.config.ts  
export default defineConfig({
  optimizeDeps: {
    include: ['react', 'react-dom', 'react-router-dom'],
    exclude: ['@vite/client', '@vite/env']
  }
});

Impact: Faster cold starts, consistent dependency handling

Current Performance Issues

1. Barrel File Usage

Problem: Two barrel files present

• src/components/themes/index.ts
• src/themes/index.ts

Impact: Prevents tree-shaking, slower builds Solution: Remove barrel files, use direct imports

2. Missing File Extensions

Problem: Import statements lack explicit extensions

// ❌ CURRENT
import App from './App.tsx'
import { getThemes } from '../../themes'

// ✅ SHOULD BE  
import App from './App.tsx'
import { getThemes } from '../../themes/index.ts'

3. No Warmup Configuration

Problem: Cold start performance is suboptimal Solution: Configure server warmup for frequently accessed files

Implementation Priority

IMMEDIATE (Critical Performance Impact)

1. Remove barrel file imports - Replace with direct imports
2. Add resolve extensions - Configure explicit extension handling
3. Configure server warmup - Improve dev server startup

SHORT TERM (Build Performance)

1. Add manual chunk configuration - Optimize bundle splitting
2. Configure dependency pre-bundling - Improve cold start times
3. Add explicit file extensions - All import statements

LONG TERM (Advanced Optimizations)

1. Dynamic imports for themes - Code splitting for theme system
2. Service worker integration - Cache theme assets
3. Module federation - If theme system becomes shared

Monitoring Standards

• Bundle size analysis: Use npm run build -- --analyze
• Dev server startup time: Should be < 1 second after warmup
• Hot reload performance: Changes should reflect in < 200ms
• Build time targets: Production build < 30 seconds

File Size Targets

• Main bundle: < 200KB gzipped
• Theme chunks: < 50KB each
• CSS bundles: < 100KB total
• Asset optimization: Images < 500KB each

Implementation Checklist

• Remove barrel file exports
• Add resolve extensions configuration
• Configure server warmup paths
• Add manual chunk configuration
• Configure dependency pre-bundling
• Add explicit import extensions
• Set up bundle analysis
• Monitor performance metrics