I believe `React.createClass` will be deprecated in the future in favor of ES6 classes. As another commenter mentioned, explicit `.setState` makes it much easi

I believe `React.createClass` will be deprecated in the future in favor of ES6 classes. As another commenter mentioned, explicit `.setState` makes it much easier to see where in your code you're triggering changes. It also helps you think, "okay, I am mutating the state here... is that really what I want to do?"