Love Svelte but well, raw DOM manipulation isn't fast either. I have a recursive Svelte tree component which, as I collapse node's contents, destroys all of its children. Which is fine with small trees but once they get big there's a noticeable lag between collapsing/uncollapsing trees. Once I deploy the site it gets faster but still, destroying children components is slow.

I think I'll try next just toggling visibility instead and skipping the removal of children. Sure this is a bit of edge-case but there's no definite silver-bullet here. Don't know about Svelte internals if this is something they could do eg hiding the components before destroying them. But well it'll still jank (but not as visibly) as everything is done in the same UI thread.

Virtual list of course would probably be the optimal solution.