Frontend Performance & Code Splitting: Speeding up React & Vite Apps
Advanced frontend performance techniques: Component Lazy Loading, Tree-Shaking, Vite bundle optimization, and achieving a 100 Lighthouse score.
Mohamed Ben Yahia
FULL STACK DEVELOPER
Speed Drives User Conversion & SEO
In modern web development, load performance directly dictates conversion metrics and search rankings. Every 100ms optimization in INP (Interaction to Next Paint) measurably improves retention.
1. Dynamic Imports & Lazy Loading in React & Vite
Rather than serving a monolithic JavaScript bundle upfront, Code Splitting defers non-critical modules until user navigation:
`tsx
import React, { Suspense, lazy } from 'react';
// On-demand route loading
const AnalyticsDashboard = lazy(() => import('./pages/AnalyticsDashboard'));
const SettingsPanel = lazy(() => import('./pages/SettingsPanel'));
export function AppRouter() {
return (
<Suspense fallback={<div className="animate-pulse p-6">Loading module...</div>}>
<Routes>
<Route path="/dashboard" element={<AnalyticsDashboard />} />
<Route path="/settings" element={<SettingsPanel />} />
</Routes>
</Suspense>
);
}
2. Vite Chunk Splitting Strategy (`vite.config.ts`)
Split large third-party packages (recharts, framer-motion) into dedicated vendor chunks for browser caching efficiency:
`typescript
import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';
export default defineConfig({
plugins: [react()],
build: {
rollupOptions: {
output: {
manualChunks: {
vendor: ['react', 'react-dom'],
ui: ['framer-motion', 'lucide-react'],
charts: ['recharts'],
},
},
},
},
});
3. Core Web Vitals Checklist 2026
fetchpriority="high") with WebP/AVIF formatting.