Thanks, fluxible looks like it might be the best isomorphic solution available right now, and the fromJS() and toJS() functions are what I would need.

I guess I was initially hoping to use immutable data for the performance benefit; being able to implement a fast shouldComponentUpdate() with a simple equality check.

But I wonder how toJS() and fromJS() performance-wise... if they have to create new objects by deeply copying the objects, maybe that would be just as bad as doing no shouldComponentUpdate optimization.

I guess I'll just stick to the "premature optimization is the root of all evil" concept, and try to get something working with carefully mutable data first.