ReactNative Firebase Application : Firebase App named ‘[DEFAULT]’ already exists (app/duplicate-app)

http://knowledge-cess.com/reactnative-firebase-application-firebase-app-named-default-already-exists-app-duplicate-app/

If by change you are getting following exception 

Firebase App named ‘[DEFAULT]’ already exists (app/duplicate-app)

Then do the following fix :

Check whether firebase is already initialised or not before calling firebase.initializeApp

if (!firebase.apps.length) {
  firebase.initializeApp(firebaseConfig);
}