firestore get single document by id code example

Example 1: get data in from a collection firestore

db.collection("users").get().then((querySnapshot) => {
    querySnapshot.forEach((doc) => {
        console.log(`${doc.id} => ${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()))

Example 3: firestore get id of new document

async function addCity(newCity) {
  const { id } = await db.collection("cities").add(newCity)
  console.log("the new city's id:", id)
}