Expo firebase 7.9.0无法获取downloadUrl

npm install firebase

import firebase from 'firebase/app';
import 'firebase/storage';

const firebaseConfig = {
  apiKey: "YOUR_API_KEY",
  authDomain: "YOUR_AUTH_DOMAIN",
  projectId: "YOUR_PROJECT_ID",
  storageBucket: "YOUR_STORAGE_BUCKET",
  messagingSenderId: "YOUR_MESSAGING_SENDER_ID",
  appId: "YOUR_APP_ID",
};

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

import * as ImagePicker from 'expo-image-picker';

async function uploadImage() {
  const { status } = await ImagePicker.requestCameraRollPermissionsAsync();
  if (status !== 'granted') {
    console.log('Permission denied');
    return;
  }

  const result = await ImagePicker.launchImageLibraryAsync();
  if (!result.cancelled) {
    const fileUri = result.uri;
    const storageRef = firebase.storage().ref().child('your_folder_name/' + result.fileName);
    const snapshot = await storageRef.put(fileUri);

    snapshot.ref.getDownloadURL().then((downloadURL) => {
      console.log('File available at', downloadURL);
    }).catch((error) => {
      console.error('Error getting download URL:', error);
    });
  }
}