snapshot.data() firestore code example
Example 1: collection get firesotre
async getMarker() {
const snapshot = await firebase.firestore().collection('events').get()
return snapshot.docs.map(doc => doc.data());
}
Example 2: get one document based on id in firestore
//retrieve one document and save it to userDetails
const [userDetails, setUserDetails] = useState('')
db.collection('users').doc(id).get()
.then(snapshot => setUserDetails(snapshot.data()))