如何从firebase中检索所有数据

const database = firebase.database();
const rootRef = database.ref();
rootRef.once('value')
  .then((snapshot) => {
    const data = snapshot.val();
    // 处理数据
  })
  .catch((error) => {
    console.error(error);
  });

const firestore = firebase.firestore();
const collectionRef = firestore.collection('collectionName');
collectionRef.get()
  .then((querySnapshot) => {
    querySnapshot.forEach((doc) => {
      const data = doc.data();
      // 处理数据
    });
  })
  .catch((error) => {
    console.error(error);
  });