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World Congress 2025 • Aug 20, 2025 • Session details

A Practical Guide to Reducing Bundle Size

Stephen Cooper

Are TypeScript decorators and barrel exports secretly bloating your web application? Discover how to optimize tree shaking and write minification-friendly code to slash your bundle size by 40%.

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#1 about 2 min

Overview of component libraries and bundle optimization scope

Context on component library structures and the explicit motivation to shrink payload footprint for faster rendering.

#2 about 2 min

Benefits of reducing client browser bundle size

How smaller client modules improve user experience, reduce parsing execution timeouts, and directly boost web vitals metrics.

#3 about 2 min

Understanding tree shaking concepts in modern bundlers

Exploring the process of dropping unused abstract syntax tree logic branches from finalizing production output.

#4 about 2 min

Risks of module side effects in bundled output

Why unexpected externally visible behaviors or top-level logic prevents tooling from safely removing uncalled module definitions.

#5 about 3 min

Configuring side effect flags for web bundlers

Signaling side-effect-free code execution using explicit package configurations allows engines to drop dead style definitions.

#6 about 2 min

Optimizing pure functions with manual bundler annotations

Marking unattached variables or isolated components as pure enables aggressive elimination of unused complex logic blocks.

#7 about 3 min

Why TypeScript decorators prevent effective tree shaking

Identifying how transpiled configuration decorators leak reference properties that block static analysis tooling from correctly eliminating dependencies.

#8 about 2 min

Avoiding barrel file exports for better dependency isolation

Bypassing global star exports from combined barrel definitions allows compilation interfaces to correctly isolate independent functions.

#9 about 3 min

Integrating bundle size regression testing into pull requests

Tracking overall payload metric changes with continuous integration assertions automatically flags unexpected logic inclusions during code reviews.

#10 about 2 min

Inspecting compiled bundles with visual diagnostic heat maps

Utilizing modern source map visualization panels helps developers immediately diagnose unexpectedly heavy or grouped logic blocks.

#11 about 2 min

Fundamentals of JavaScript minification and internal variable mangling

Stripping execution files of specific semantic descriptors and physical spacing compresses the code text into tiny, functionally identical footprints.

#12 about 4 min

Shrinking module classes with native JavaScript private properties

Adopting the native hash modifier over standard TypeScript restrictions ensures final build processes can safely obscure internal identifiers.

#13 about 5 min

Code restructuring techniques to maximize repeated property minification

Adopting numerical error replacements and explicit inversion injection behaviors drastically scales down identifier repetition in heavily shared architecture components.

Matching moments

2:54 min

Reducing JavaScript bundle sizes with build tools

Shem Magnezi Shem Magnezi · WWC 2025

5:52 min

Understanding the role of bundlers in tree shaking

Francesco Novy Francesco Novy

4:10 min

Benchmarking execution speed and bundle size across module systems

Jolo Jolo · WWC 2024

4:18 min

Reducing JavaScript bundle sizes for multiplied carbon savings

Lorenzo Pieri · LIVE

4:29 min

Reducing initial bundle size via dynamic component imports

Eileen Fürstenau Eileen Fürstenau · WWC 2024

2:00 min

Optimizing bundle sizing using customized Emscripten compilation flags

Paweł Aniszewski Paweł Aniszewski · Europe 2026 Virtual

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