The problem with composition is much deeper than you suggest. LiveView’s component structure is completely flat. Components are mounted with global ids, and the responsibility of choosing those ids is passed onto the developer. The id requirement itself does not compose; each parent must pass an id to its children, which means it must have an id of its own, and so on. The concerns of the components become quite badly intertwined, defeating their purpose. It’s actually a pretty textbook example of what Hickey was talking about.
I do not know LV’s engine in extreme detail, but I know enough to know that it’s mostly template-based and treats conditionals as first-class citizens. This structure is actually very problematic, because it means the component tree is not a strict superset of the DOM tree as it would be in, for example, React. That in turn makes implicitly mounting stateful components by their tree positions very messy if not outright intractable. So instead the engine cheats with global ids.
This can be fixed, but it’s not easy. The whole thing probably has to be rewritten from scratch, the template approach thrown away in favor of a full element-level tree, the server/client protocol rewritten, and so on. Backwards compatibility would likely be broken because it’s good to know whether a component should be unmounted during the local diff cycle, so the “teleportation” ability should probably be removed.
It’s a lot of work. So the question becomes: does anyone using Phoenix actually care? And given that you are the only individual I have ever seen (other than myself) voice this concern, I think the answer is “not really”.
This actually cannot be fixed as far as I can tell. It’s an inherent tradeoff with latency.
I strongly recommend you avoid reading the thread where I unsuccessfully attempted to explain this to I think at least four different people lol.
Strangely it is actually possible, as after a week of wasting my time thinking about it I realized that you can abuse the client-side phx-remove binding to run a callback on the server. Utterly cursed, of course.
