db.collection("users").get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
console.log(`${doc.id} => ${doc.data()}`);
});
useEffect(() => {
db.collection('posts')
.orderBy('timestamp', 'asc') // optional
.onSnapshot((snapshot) => {
setPosts(
snapshot.docs.map((doc) => {
return doc.data();
})
);
});
}, []);//retrieve one document and save it to userDetails
const [userDetails, setUserDetails] = useState('')
db.collection('users').doc(id).get()
.then(snapshot => setUserDetails(snapshot.data()))