Learn about lesser-known web performance bottlenecks connected to excessive JavaScript usage, like long tasks, large bundle sizes, and hydration issues.

MDN Blog is a platform or publication associated with Mozilla Developer Network (MDN), offering articles, updates, and resources for web developers. Readers can find tutorials, documentation, and best practices for web development technologies such as HTML, CSS, JavaScript, and web APIs. With contributions from experts and community members, MDN Blog provides  insights and guidance to help developers build better web experiences.

MDN Blog

Web performance can be hit hard by JavaScript issues like long tasks, large bundle sizes, and hydration. Long tasks lock the main thread, blocking user interactions; large bundles slow down download, parse, and execution times; and hydration can delay interactivity in server-rendered pages. Strategies to address these include breaking up JavaScript work, using Web Workers, implementing tree shaking, code splitting, lazy loading, and considering alternatives to popular JavaScript frameworks that may improve performance.

Fixing your website's JavaScript performance

the best way to fix your shitty javascript performance is to not be a shitty developer and learn how to ACTUALLY code.
or just use typescript, the language for people too stupid to figure out how to use js properly (ie new devs that don’t REALLY know how to develop).

Thanks for this article. It really helps put things in to perspective. The need to be more granular with how I roll out code has been on my mind. Now I can hone in on specifics like reducing parser blocking time and execution time. I liked all the peripheral knowledge I got on Web APIs too.