You're asking that because you're concerned about performance, right?

The thing that makes React really cool is that you only add optimization hints rather than refactor your code to optimize perf. So for your example: what's the most logical way to write your app if you didn't care about perf? It would be to still `setState()` on the entire list, right?

If it becomes slow, you can override `shouldComponentUpdate()` on your list item to get your perf where you want it to be. This should be a whole separate blog post though :)