[4.0.0-beta4] hx-preload doesn't support "intersect" or "revealed"

[YamiOdymel]

I hope there’s an aggressive way to prefetch links on mobile when a link enters the viewport.

Google has also been promoting the Speculation Rules API lately, which allows prefetching and prerendering pages in the background. So I was hoping HTMX would have something similar to it.

While HTMX 4 documents that “Preload can listen to any event name supported by htmx trigger specs.", it doesn’t support intersect or revealed (because they aren’t regular events?). In that case, “supported by htmx trigger specs” sounds ambiguous.

[MichaelWest22]

Yeah it only supports events and these are not events but custom intersection observers instead. If we wanted to support these observers in the preload extension we would have to special case them in the preload extension and setup intersection observers here as well.

If you want to preload a request when a div comes into view you could add a hx-get to it on a wrapping div with these triggers and set hx-swap to none so that it will trigger the request but not touch the dom. As long as your response returns the correct cache control headers this will then get the request from cache if the user performs the proper action.