Hydration Attributes

[plutoniumm]

Describe the problem

Svelte Currently operates in binary, SSR or Client side (admittedly this being heavily customisable to reasonably fine detail), there however is still no way to control the hydration at multiple stages of life cycle specifically at

• Server Side: Directly Rendered
• Client Side:
• • On Load
• • On Visible
• • On Idle

Describe the proposed solution

The easiest would probably be an Astro like solution where on:load, on:visible and on:idle attributes are directly used, considering svelte's compiler like nature, it makes it easy to abstract away this functionality at least on a component level from end user, using requestIdleCallback, IntersectionObserver etc, (We might need to add polyfills if this feature is implemented)

Alternatives considered

Currently doing this manually or with slightly prebuilt libraries like svelte-visibility-change

Importance

would make my life easier

[cudr]

Related to sveltejs/kit#1390