Background Listener is firing multiple times

[SamKissee]

Describe the bug
When attaching the background listeners, the console logs or any other action is fire 20+ times simultaneously

To Reproduce
Place useEffect with eventListener
Launch App
Go to Health and Add Data
View Response in Logs

Expected behavior
Listener should only fire once when new sample is received.

Smartphone (please complete the following information):

• Device: iphone15 simulator and iphone 15 pro max physical device
• OS: 17

Additional context
Located in our app container
React.useEffect(() => { new NativeEventEmitter(NativeModules.AppleHealthKit).addListener( 'healthKit:Running:new', async () => { console.log('--> Running observer triggered'); }, ); });

Data received from logs
LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered LOG --> Running observer triggered

[iMonk777]

Hi @SamKissee , did you find any solution for this issue? We are facing the same thing.

[kyo504]

@SamKissee , @iMonk777 After digging this, I found that the problem happens because startObserving function is called twice(one by initializeBackgroundObservers and the other when the first listener is added). IMO, if self.hasListeners is set to YES, we should ignore duplicate operation(which means adding observers).

I heard that there is massive factoring is on the way, so I'm not sure it's ok to submit a pr(maybe maintainers have already fixed this issue?!). Instead, if you want to fix this issue, you can apply the following simple patch using patch-package or yarn patch

-(void)startObserving {
    if (self.hasListeners) {
        return;
    }

    ...rest of your codes
}

[iMonk777]

Thanks @kyo504 , we will probably try this in a future release