How do define derived signals?

[frnsys]

Is it possible to derive read/write signals (so not memos) of fields or elements of a signal?

For example, in the todo example the TodoEntry component takes the entire group of todo items:

fn TodoEntry(mut todos: Signal<HashMap<u32, TodoItem>>, id: u32) -> Element {

My use-case is similar to this except that I'd rather have this component take only a single TodoItem, without needing to take the entire group.

Is this possible? I figure I could hack it together by using a separate signal and using with use_effect to keep things in sync, but I was hoping there was a proper way.

I looked through the documentation but wasn't able to find anything.

[ealmloff]

You can create a read only view of a signal with Readable::map, but you cannot create a writable view. See #3610 for more information