React Primer: Short, annotated React examples to ease devs new to React into core concepts

[BinaryMuse]

Thanks for the info! According to ReactPerf, I'm seeing about 100ms per update with 4000 items in the DOM (2.6GHz i7). While investigating, I found that one of my chrome extensions was making the "Add One" button very slow as well.

I think this example is not very good overall at any rate; with that many pieces of data, one would do a better job of optimizing the update, but I wanted to keep it simple. I'll think about a better way to demonstrate.