1. If you're not passing the backbone models to React components, this sounds fine. backbone models as props ends up being really painful because of how mutable they are, and when we tried to manage that with mixins, it was buggy and caused problems (note: I'm not familiar with the actual mixin we used there and whether there was a better way to do it). Since most flux implementations are pretty stateful/mutable themselves, using mutable backbone models there, so long as you copy data out to pass to react views, seems safe. Though I'm excited long-term about the immutable flux implementations (https://github.com/rackt/redux)
2. We had a library originally written by Ben Alpert (now core react team) that handles all of our interactive svgs [1]. Since KA has a lot of legacy code there, and there hasn't been an immediate benefit to porting it (which would take a pretty significant time investment, on the [very roughly] order of a couple dev-months), this is still mutable jQuery/raphael code. There have been a lot of talks of eventually porting this to react, but the immediate need for it hasn't been there yet. However, I did write a React wrapper around much of this code which is used by newer interactive widgets [2].
2. We had a library originally written by Ben Alpert (now core react team) that handles all of our interactive svgs [1]. Since KA has a lot of legacy code there, and there hasn't been an immediate benefit to porting it (which would take a pretty significant time investment, on the [very roughly] order of a couple dev-months), this is still mutable jQuery/raphael code. There have been a lot of talks of eventually porting this to react, but the immediate need for it hasn't been there yet. However, I did write a React wrapper around much of this code which is used by newer interactive widgets [2].
[1]: https://github.com/Khan/khan-exercises/blob/master/utils/gra...
[2]: https://github.com/Khan/perseus/blob/master/src/components/g...