Unable to call swift function from objective-c in react-native - ios

Question

I'm fairly new to objective-c and swift so forgive me if this sounds dumb. Basically what I'm trying to do is *expose** a swift function to both react-native(so it can be used in JS) and to be used in objective-c. The issue I'm having is this dreaded "Duplicate interface definition for class...". I have researched and tried everything it seems but can not get rid of this error. I'm starting to wonder if is possible to do this. It seems so simple yet I just can't figure it out!
Here is my code:
AppDelegate.m
#import "MyApp-Swift.h"
#import "MyApp-Bridging-Header.h"
MyApp-Swift.h
#import "React/RCTEventEmitter.h"
#interface Counter : RCTEventEmitter
- (void)start;
- (void)stop;
#end
MyApp.swift
import Foundation
import UIKit
#objc(Counter)
class Counter: RCTEventEmitter {
#objc func start(){
}
#objc func end(){
}
}
MyApp-Bridging-Header.h
#import <Foundation/Foundation.h>
#import "React/RCTBridgeModule.h"
#import "React/RCTEventEmitter.h"
#interface RCT_EXTERN_MODULE(Counter, RCTEventEmitter)
RCT_EXTERN_METHOD(start);
RCT_EXTERN_METHOD(end);
#end
Inside AppDelegate.m didFinishLaunchingWithOptions() function
Counter* CounterInstance = [[Counter alloc] init];
[CounterInstance start];
If I remove the code from MyApp-Swift.h then I get the error "No visible #interface for..." BUT fixes the "Duplicate interface error" in MyApp-Bridging-Header.h. It seems like it contradicts each other!? How are you supposed to call a swift function from objective-c while also exposing the same function to JS?

Answer 1

I'm doing something similar in a project, and my setup looks like this:
Counter.m
#import "React/RCTBridgeModule.h"
#import "React/RCTViewManager.h"
#interface RCT_EXTERN_MODULE(Counter, NSObject)
RCT_EXTERN_METHOD(start)
RCT_EXTERN_METHOD(stop)
#end
Counter.swift
import React
#objc(Counter)
class Counter: RCTEventEmitter {
#objc func start() { /* ... */ }
#objc func stop() { /* ... */ }
}
and at the call site:
#import "YOURAPP-Swift.h" // the compiler creates this for you. don't edit!
-(void) foo {
Counter* cnt = [Counter new];
[cnt start];
}
(no other files used or modified. In particular, the bridging header isn't needed here)
I've found https://teabreak.e-spres-oh.com/swift-in-react-native-the-ultimate-guide-part-1-modules-9bb8d054db03 very helpful when I started doing this.