firebase update realtime database

1db.collection("cities").add({
2    name: "Tokyo",
3    country: "Japan"
4})
5.then(function(docRef) {
6    console.log("Document written with ID: ", docRef.id);
7})
8.catch(function(error) {
9    console.error("Error adding document: ", error);
10});
11

1function writeUserData(userId, name, email, imageUrl) {
2  firebase.database().ref('users/' + userId).set({
3    username: name,
4    email: email,
5    profile_picture : imageUrl
6  });
7}

1await firebase.database().ref().update(updates);

1<a href="#" >Add Data</a>