UPDATE 2 (Dec 7th 2014): The mixin now also supports transitions! It works a lot better after creating a diffing "algorithm" that enables the mixin to leverage the .appended() method.
I've been fiddling around with React and Masonry this weekend, and made a mixin than seems to work ok for now.
There is no official fully working npm module available from what I can see atm, so for now you will need to include Masonry as a script tag dependency:
<script src='//cdnjs.cloudflare.com/ajax/libs/masonry/3.1.5/masonry.pkgd.min.js' />
An example of the mixin in use - with the mixin itself following:
For some reason (might be application specific) I had to force the browser
resize event when the component is unmounted and remounted.
The main drawback with this solution would be that you aren't leveraging the
prepended methods of Masonry, which improves performance quite a bit. So the next step would be to relieve React of its rendering duties in this case and write a custom renderer for the component.
If anyone has a better solution, please let me know by commenting! :-)