I timed the React example you posted. It looks like the unoptimized version is about 200ms by default and about 8-20ms after the optimization. The version of Re

I timed the React example you posted. It looks like the unoptimized version is about 200ms by default and about 8-20ms after the optimization. The version of React I'm testing doesn't have some of the major perf benefits that React v0.5 has - so I suspect even the unoptimized test case with v0.5 would come in around 100ms. The optimized version would likely take around 8-15ms if I had to guess. I have a recent-ish macbook pro like the author. edit: By the way, I really like the creative solution that the author discovered with mouse hovering.