function rtdb_and_local_fs_presence()

in presence-firestore/public/index.js [66:114]

• 31 lines of code
• 2 McCabe index (conditional complexity)

function rtdb_and_local_fs_presence() {
    // [START rtdb_and_local_fs_presence]
    // [START_EXCLUDE]
    var uid = firebase.auth().currentUser.uid;
    var userStatusDatabaseRef = firebase.database().ref('/status/' + uid);

    var isOfflineForDatabase = {
        state: 'offline',
        last_changed: firebase.database.ServerValue.TIMESTAMP,
    };

    var isOnlineForDatabase = {
        state: 'online',
        last_changed: firebase.database.ServerValue.TIMESTAMP,
    };

    // [END_EXCLUDE]
    var userStatusFirestoreRef = firebase.firestore().doc('/status/' + uid);

    // Firestore uses a different server timestamp value, so we'll 
    // create two more constants for Firestore state.
    var isOfflineForFirestore = {
        state: 'offline',
        last_changed: firebase.firestore.FieldValue.serverTimestamp(),
    };

    var isOnlineForFirestore = {
        state: 'online',
        last_changed: firebase.firestore.FieldValue.serverTimestamp(),
    };

    firebase.database().ref('.info/connected').on('value', function(snapshot) {
        if (snapshot.val() == false) {
            // Instead of simply returning, we'll also set Firestore's state
            // to 'offline'. This ensures that our Firestore cache is aware
            // of the switch to 'offline.'
            userStatusFirestoreRef.set(isOfflineForFirestore);
            return;
        };

        userStatusDatabaseRef.onDisconnect().set(isOfflineForDatabase).then(function() {
            userStatusDatabaseRef.set(isOnlineForDatabase);

            // We'll also add Firestore set here for when we come online.
            userStatusFirestoreRef.set(isOnlineForFirestore);
        });
    });
    // [END rtdb_and_local_fs_presence]
}