Conditionally loading JS libraries

[rhcarvalho]

Oh I didn’t find this thread yesterday! For anyone landing here in the future, here’s how to configure esbuild to use JS dynamic imports, and lazy load parts of the app on demand:

Is it possible to have page-specific javascript with LiveView?

This is one of the two best threads that come up from search on the topic, so reviving it with an up-to-date solution for the benefit of all. Just like the OP, I wanted to use a heavy JS library in a single page without compromising the bundle size for the rest of the app. Nowadays Phoenix projects use esbuild by default, and modern browsers support ESM modules and dynamic import. To my surprise, asking Gemini 3 produced a reasonable output, hinting at the right things. In a nutshell: Updat…