Strange issue ‘Cannot find type ‘RCTResponseSenderBlock’ in scope’ on Swift module React Native

I had this same issue and discovered I had to add the import to my main bridge file.

#import <React/RCTBridgeModule.h>
#import <React/RCTViewManager.h>

I out which file was set by looking at the Build settings under Swift Compiler – General -> Objective-C Bridging Header which appears to be the default for the app.