When I look at any of the myriad JavaScript UI libraries out there, I now ask two questions: Does data flow in one direction? Do updates to the UI happen intelligently? I am a fan of Facebook's ReactJS library because of its DOM diffing (via the "virtual DOM") and one-way data binding. React is a tool I use every day and have come to enjoy (sans-JSX), but I am always on the lookout for way to do t