ios - How do I loop through and get all the keys of the nested nodes in firebase?

Question

I am trying to get the keys of the nested nodes in Firebase and I am not sure how to do this.

For example in this case:

example

How do I know that 2,3,4 exist within 1?

I am thinking of putting a values in a list seperately in firebase. But is there a smarter way of doing this? Is there a more efficient way of getting the keys of all the nested nodes in Firebase?

Answer 1

Waitting for answers