Cambios primeros

App.js

 
 
 // Import the functions you need from the SDKs you need
-import { initializeApp } from "firebase/app";
+// import { initializeApp } from "firebase/app";
+import firebase  from 'firebase';
+// expo install firebase
 // TODO: Add SDKs for Firebase products that you want to use
 // https://firebase.google.com/docs/web/setup#available-libraries
 
 };
 
 // Initialize Firebase
-const app = initializeApp(firebaseConfig);
+const app = firebase.initializeApp(firebaseConfig);
 
 
 const styles = StyleSheet.create({

package.json

   "dependencies": {
     "expo": "~42.0.1",
     "expo-status-bar": "~1.0.4",
-    "firebase": "^9.0.2",
+    "firebase": "8.2.3",
     "react": "16.13.1",
     "react-dom": "16.13.1",
     "react-native": "https://github.com/expo/react-native/archive/sdk-42.0.0.tar.gz",