As you begin developing more interesting and complex React Native applications, you could possibly reach a point where executing certain code would be only possible (or significantly improved) in the native layer. This allows for executing data processing that's faster in the native layer when compared with JavaScript, and for accessing certain native functionality that isn't otherwise exposed, such as file I/O, or leveraging existing native code from other applications or libraries in your React Native app.
This recipe will walk you through the process of executing some native Objective-C or Swift code and communicating with the JavaScript layer. We'll build a native HelloManager module that will greet our user with a message. We'll also show how to execute native Objective-C and Swift code, taking in arguments, and showing several...