How to Fix Common Code Splitting Mistakes and Boost Web App Performance

Code splitting is a widely used technique that breaks large JavaScript bundles into smaller, on-demand chunks to improve initial load times, but improper implementation can slow applications down rather than speed them up. Common pitfalls include over-splitting, which generates too many small chunks and increases network request overhead, and under-splitting, where chunks remain too large to deliver real performance gains. Developers also face issues with incorrect splitting points that create waterfall loading delays, as well as shared module duplication that inflates total download size across multiple chunks. Large third-party libraries can further undermine splitting efforts by bloating otherwise targeted chunks. Identifying these problems requires careful analysis of bundle structure and performance metrics before applying targeted fixes.