firebase update return result code example
Example: firebase update return result
var fredNameRef = new Firebase('https://docs-examples.firebaseio.com/samplechat/users/fred/name');
fredNameRef.on('value', function(snap) {
console.log(snap.val());
});
fredNameRef.update({ first: 'Wilma', last: 'Flintstone' });
credit: https://stackoverflow.com/questions/36105690/how-to-return-success-data-after-update-in-firebase