null is not an object (evaluating 'RCTAsyncStorage.multiMerge')

I recently upgraded to Expo SDK 43.

I am now getting this error:

The line of code throwing it is:

if (!RCTAsyncStorage.multiMerge) {

I am on the latest version of AsyncStorage.

This seems to be due to my usage of firebase-js-sdk.

Unfortunately as this is an iOS/Android/Web project, it's necessary.

When I mock my Firebase exports, everything works:

const auth = () => {};

const analytics = () => {};

export default { auth, analytics };

But when I use the firebase-js-sdk functions, I get the above message.

This code causes an error (whichever version of auth I use)

let auth = initializeAuth(config, {
  persistence: getReactNativePersistence(AsyncStorage),
});
//let auth = getAuth(config);
let analytics = getAnalytics(config);

export default { auth, analytics };

from null is not an object (evaluating 'RCTAsyncStorage.multiMerge')