Engineering Reference · Webpack 5 & Vite 5+
JavaScript Bundle Analysis
& Code Splitting Architectures
A production-grade reference for frontend engineers who care about performance. Deep-dive into route-based code splitting, advanced tree-shaking, and build pipeline internals — with quantified metrics and real configuration for both Webpack 5 and Vite 5+.
Modern frontend architectures demand rigorous payload control. Proper code splitting reduces initial JavaScript by 40–65%, improving Time to Interactive by 800–1200ms on mid-tier mobile devices. This reference covers the configuration, debugging, and CI validation workflows that make the difference in production.
What Proper Optimisation Delivers
Explore the Reference
Three interconnected topic areas — each with section overviews, focused sub-articles, and deep-dive implementation guides.
Dynamic imports, route-level chunk boundaries, prefetch/preload strategies, and vendor chunk isolation — with Webpack 5 and Vite 5+ configurations.
- →Dynamic Import Patterns for On-Demand Loading
- →Preventing Waterfall Requests with Dynamic Import Maps
- →Implementing Route-Level Code Splitting in SPAs
- →React.lazy with Route Transitions
- →Prefetch & Preload for Critical Routes
- →Route-Based Prefetching in Next.js
- →Vendor Chunk Isolation & Third-Party Management
- →Configuring Vite manualChunks for Vendor Isolation
sideEffects configuration, barrel file elimination, CJS→ESM conversion, and dead-code removal pipelines for production bundles.
- →Configuring sideEffects for Optimal Tree-Shaking
- →Auditing sideEffects in Large npm Packages
- →Converting CJS Libraries to ESM for Better Bundling
- →Fixing Tree-Shaking Failures with Webpack 5
- →Eliminating Dead Code with Modern Build Tools
- →Refactoring Barrel Files to Reduce Bundle Bloat
- →Replacing Barrel Exports with Direct Module Imports
Webpack & Vite internals, module resolution algorithms, source map workflows, ES Modules vs CommonJS interop, and dev-server optimisation.
- →Vite Module Graph & Dependency Resolution
- →Optimizing Dev Server Startup for Large Monorepos
- →Webpack Chunk Generation Lifecycle Explained
- →Fixing Source Map Mismatches in Webpack 5
- →Source Map Generation & Debugging Workflows
- →ES Modules vs CommonJS in Bundlers
- →Configuring Module Resolution Aliases in Vite
Start Here
New to the reference? These four articles cover the highest-impact techniques first.