Get Current value of a Firebase Node? (Using AngularJS)

Question

Trying to update the information in a node by adding an amount to the current value. I can't find a way to reference the current value so I can add my value. How can you call the current value?

.update({total: "current-value?" + $scope.user.amount}).then(function() {       
    });

Answer 1

As it looks like you might not be able to pull the current value of a node without using a function, that is what I did:

snap.ref().child('gold/total').transaction(function(currentVal) {
        return (currentVal || 0) + $scope.user.amount;
     }); 

The current value of the node is captured with "currentVal", and then it can be passed along so that the addition can be performed.