The React Native library has grown over time to encompass the majority of the native application programming interfaces that we need to build sophisticated applications for mobile devices. As we've seen, we can access numerous native user interface components that are available on all devices, such as list views, images, and text, as well as platform-specific UI components, such as the tab bar on iOS. We've also used some of the many available native APIs, such as those used for alerting and animation.
There will be, however, occasions where the components and APIs that exist in the React Native library are not sufficient. Luckily, React Native provides an extensible framework for writing custom native modules in platform-specific code and making them available in our application's JavaScript. The ability to create native modules is one of the most powerful parts of the React Native library because it means that there is no application that can...