What is React Native?

Earlier in this book, I introduced the notion of a render target, the thing that React components render to. The render target is abstract as far as the React programmer is concerned. For example, in React, the render target can be a string, or it could be the Document Object Model (DOM). Therefore, your components never directly interface with the render target because you can never make assumptions about where the rendering is taking place.

A mobile platform has UI widget libraries that developers can leverage to build apps for that platform. On Android, developers implement apps using Java or Kotlin, while, on iOS, developers implement Objective-C or Swift apps. If you want a functional mobile app, you’re going to have to pick one. However, you’ll need to learn both languages, as supporting only one of two major platforms isn’t realistic for success.

For React developers, this isn’t a problem. The same React components that...