Auto-increment A Value In Firebase

Answer :

Here's an example method that increments a single counter. The key idea is that you are either creating the entry (setting it equal to 1) or mutating the existing entry. Using a transaction here ensures that if multiple clients attempt to increment the counter at the same time, all requests will eventually succeed. From the Firebase documentation (emphasis mine):

Use our transactions feature when working with complex data that could be corrupted by concurrent updates

public void incrementCounter() {     firebase.runTransaction(new Transaction.Handler() {         @Override         public Transaction.Result doTransaction(final MutableData currentData) {             if (currentData.getValue() == null) {                 currentData.setValue(1);             } else {                 currentData.setValue((Long) currentData.getValue() + 1);             }              return Transaction.success(currentData);         }          @Override         public void onComplete(FirebaseError firebaseError, boolean committed, DataSnapshot currentData) {             if (firebaseError != null) {                 Log.d("Firebase counter increment failed.");             } else {                 Log.d("Firebase counter increment succeeded.");             }         }     }); } 

A new feature is added to firestore to autoincrement values. As simple as

document("fitness_teams/Team_1").   updateData(["step_counter" : FieldValue.increment(500)]) 

refer link: https://firebase.googleblog.com/2019/03/increment-server-side-cloud-firestore.html

Used below code in my project.

var firestore = Firestore.instance; firestore.collection('student').document('attendance').updateData({'total_attendace': FieldValue.increment(1)});