Cloud Firestore Event Types
onSnapshot
- Cloud Firestore offers the onSnapshot event type, allowing developers to listen for real-time changes to a document or a query result.
- It triggers whenever the document or query result changes, providing a powerful tool for building real-time applications.
- The onSnapshot event provides a snapshot of the current state of the data and is useful for listening to changes in specific documents or query results
Example: Listening for onSnapshot Changes
firebase.firestore().collection('users').doc('user1').onSnapshot(function(doc) {
var data = doc.data();
console.log("New data:", data);
});
Output
Executing the above code will continuously listen for changes to the document with the ID ‘user1’ in the ‘users’ collection in Cloud Firestore and log the new data whenever it changes.
Firebase Event Types
Firebase provides event types such as value, child_added, onSnapshot, and onAuthStateChanged across its services like Realtime Database, Cloud Firestore and Authentication. These event types enable developers to build real-time applications and trigger actions based on changes in data or authentication state.
In this article, We will learn about these event types are essential for creating dynamic and interactive applications with Firebase in detail.