The use of setState in React strikes me as a code smell. React has two ways to provide state for components: props and state. I prefer using React in a more functional style: your model is managed separate from the view and updates are handled just by re-rendering the view from the top (which React handles efficiently).
In other words: I haven't really seen a need for a library like Bacon when using React, because React provides a means for generating a view without "wiring it up" as you do in a typical reactive app. You just regenerate the view whenever an action is taken that might have changed the model.
I agree. Using setState within a nested component should be limited to UI-only functionality, such as tab views or toggling menus or the like.
Even then, if one were to have a single object that store the entire state of the application, this object could easily be saved to localStorage or pushed to the network for syncing to other clients. If the user were to reload the application or perhaps resume use on another device, they would be presented with exactly what they left behind. The infrastructure and code to do so would be very trivial.
The days of state being spread over and managed by a number of objects has come to an end, at least for me.
In other words: I haven't really seen a need for a library like Bacon when using React, because React provides a means for generating a view without "wiring it up" as you do in a typical reactive app. You just regenerate the view whenever an action is taken that might have changed the model.