[Touche]

I use React and like it a lot. The biggest issue it has right now is there is no good way for a component on one branch of the tree to get information to a component in another branch. You have to talk to your parent components by having them attach a function as a property, and this simply doesn't scale to large or even medium sized applications.

[peterhunt]

This model usually works pretty well for smaller components (see http://facebook.github.io/react/blog/2013/11/05/thinking-in-...)

For larger ones, we provide lifecycle hooks so you can set up these subscriptions manually. In componentDidMount() and componentWillUnmount() you can subscribe/unsubscribe to some sort of messaging system, and when you receive the message call setState(). Usually you only need to do this in a few places and the regular React dataflow will carry you the rest of the way.

Does that make sense? We should probably write up this technique.

[skybrian]

This isn't specific to React; in large GWT apps we use an event bus. Perhaps you could do the same thing?

Or, instead of an event-based approach, you could could pass in an object and use Object.observe() to observe state changes.

It looks like React just implements the view in MVC, so you still need a separate way to observe the model.