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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.

code-splitting.com

What Proper Optimisation Delivers

40–65%
Reduction in initial JS payload via route-based splitting
800–1200ms
TTI improvement on mid-tier mobile devices
>92%
Cache hit rate with deterministic chunk naming
75%
Bandwidth reduction on repeat visits via vendor isolation