Subscribe to firebase activities with counter

subscribe_to_activities_with_counter.js

function handleActivitySubscription(snapshot) {
   snapshot.docChanges().forEach(function(change) {          
        doSomething(change.doc.data());          
      });
}

const handleActivitySubscriptionWithCounter = 
      createFnCounter(handleActivitySubscription, 1);

db.collection("activities").where("userID", "==", currentUserID)
  .onSnapshot(handleActivitySubscriptionWithCounter);