Facebook open-sourced React Native last week, so I spent a couple of days toying with it. Here are my initial thoughts, as someone who works with both iOS and Web development:

# The Good

• Immutable user interface. You no longer have to track state in both the model and the view; the latter is a function of the former. As soon as the model changes, React Native re-renders a virtual tree of the view hierarchy, then applies the delta to the native views. This approach feels superior to bindings or FRP, and is certainly light-years ahead of the Apple-MVC that ships with iOS.

• Instant feedback loop. Once you build your app in Xcode, you can instantly refresh it from within the simulator using Command + R. You can even enable auto-refresh and forget about it. I will miss this feature in non-React projects.

• Perceived performance. I haven’t experienced any hiccups while working on a simple navigation-based app. The interface is 100% native and performs like one.

# The Bad

• JavaScript.

• No Swift support. Native modules should be written in Objective-C.

• Additional abstraction layer. If you already do iOS development, you will be relearning a lot. For instance, ListView is the new UITableView.

• SDK limitations. Unless you want to subclass an unhealthy amount of UIKit using Objective-C (hint: I don’t), you will be rather restrained in what you can do out-of-the-box. I have yet to figure out how to change the barTintColor of a NavigatorIOS, the UINavigationBar equivalent.

• No Interface Builder support. I typically use storyboards as a visual representation of user flow. Perhaps more importantly, I enjoy having the freedom of using the right tool for the job.

• Component-based file structure. Handling styles, view hierarchy, and business logic all in one file is a step backwards. Poor style reusability is one direct consequence of this approach.

• StyleSheet is not CSS. You will be quickly disappointed if you adventure outside of the handful CSS-inspired properties that React Native ships with.

• Styling nested view controllers is a pain. You are taken back to the root view controller after each refresh.

# The Meh

• Flexbox. The authors missed the opportunity of offering a better API and favored sticking to the official, confusing spec instead.

• Chrome Dev Tools. Browsers are doing too much already.

Even though a good number of these issues is very likely to be addressed as the framework matures, I find the abstraction overhead off-putting considering the current limitations. On the bright side, React Native introduces concepts that could potentially change the way we build native applications, and I am looking forward to seeing how that will unfold.