HOW WE REDUCED THE SIZE OF OUR JAVASCRIPT BUNDLES BY 33%

Summary from the TLDR Web Dev newsletter

Dropbox faced performance issues due to large JavaScript bundles and decided to replace its outdated module bundler during the migration to a new web serving stack. It chose Rollup as the new bundler, which offered features like automatic code-splitting and tree shaking. Despite initial challenges, including resource-intensive builds and bugs in Rollup’s tree-shaking algorithm, the migration was successful. After the rollout, Dropbox observed a 33% reduction in JavaScript bundle sizes, a 15% reduction in total JavaScript script count, and modest improvements in page load times. This change also significantly improved front-end development velocity and reduced maintenance burden.