How to find out the length or key of the last element in the Firebase branch? In the example, this is "4". In the application, they are added in order, so you need to find out under which index to create a slip key.
{ "Question_Score" : { "1" : { "1": { "score" : "50", "user" : "user1" }, "2": { "score" : "50", "user" : "user2" }, "3": { "score" : "50", "user" : "user3" }, "4": { "score" : "40", "user" : "user4" }, }, } } 