Iterating through nested firebase objects - Javascript

How to iterate through nested firebase objects.

Publications-
            |
            |-Folder1------
            |             |-hdgjg76675e6r-
            |             |               |-Name
            |             |               |-Author
            |             |
            |             |+-hdgjdsf3275e6k
            |             |+-hd345454575e6f
            |+-Folder2

In publications I have folders and in folders I have objects (containing properties like. Name, Author)

I have iterated through folders till now.

snapshot.forEach(function (snapshot) {
    var key = snapshot.key();
    var obj = snapshot.val();
    console.log(key);
    //output => Folder1 , Folder2 etc
});

When I print obj

console.log(obj);

It displays

How do I iterate through obj variable as it contains hdgjg76675e6r , hdgjdsf3275e6k etc and further?