flowtype.js

export type Video = {
  contentID: string,
  duration: number,
}

type Props = {
  video: Video,
  onShowNext: () => void,
  onError: (message: string) => void,
};

genned.js

class SignInWrapper extends React.Component {
  render() {
    return <SignIn
      onError={(message: string) => {
        let onError$message = message
        ReactNativeCallbackManager.callNative(this.props.onError, {message: onError$message})
      }}
      onShowNext={() => {
        
        ReactNativeCallbackManager.callNative(this.props.onShowNext, {})
      }}
      video={this.props.video}
    />
  }
}

genned.swift

public class SignIn: ReactNativeComponent {
  init(onError: (message: String) -> Void, onShowNext: () -> Void, video: SimpleVideo) {
    var properties: [String: AnyObject] = [:]
    var callbacks: [Int] = []
    let registerCallback: (([String: AnyObject]) -> Void) -> Int = {fn in
      let id = ReactNativeCallbackManager.registerCallback(fn)
      callbacks.append(id)
      return id
    }
    properties["onError"] = registerCallback({args$ in
      let onError_message: String = args$["message"]! as! String
      onError(message: onError_message)
    })
    properties["onShowNext"] = registerCallback({args$ in
      
      onShowNext()
    })
    properties["video"] = {
      let video_contentID: String = video.contentID
      let video_duration: Int = video.duration
      return ["contentID": video_contentID, "duration": video_duration]
    }()
    super.init(name: "SignIn", properties: properties, callbacks: callbacks)
  }
  
  required public init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
}

ReactNativeComponent.swift

public class ReactNativeComponent: UIViewController {
	let callbacks: [Int]
	let properties: [String: AnyObject]
	let name: String

	init(name: String, properties: [String: AnyObject], callbacks: [Int]) {
		self.name = name
		self.properties = properties
		self.callbacks = callbacks
		super.init(nibName: nil, bundle: nil)
	}

	required public init?(coder aDecoder: NSCoder) {
	    fatalError("init(coder:) has not been implemented")
	}

	public override func loadView() {
		view = ReactNativeBridge.sharedInstance.createRootComponentForModule(name, initialProperties: properties)
	}

	deinit {
		ReactNativeCallbackManager.unregisterCallbacks(callbacks)
	}
}