Linked list for firestore documents - firebase

Question

I have a use case to make a linked list of documents like
{ name, next_ptr} and next_ptr is a reference to another document
I have following code and I am getting next_ptr but not getting fields belonging to next_ptr
I am getting following output
KkkGTTKjuwcGmzJzQ3Wa => FIRE => undefined
iW9lm7sYkgvuZPdVvrZE => GAS => undefined
NtTyJNjqIT79PZ6zkqtY => WATER => undefined
Expected Output
KkkGTTKjuwcGmzJzQ3Wa => FIRE => GAS
iW9lm7sYkgvuZPdVvrZE => GAS => WATER
NtTyJNjqIT79PZ6zkqtY => WATER => undefined
Code
db = defaultApp.firestore() ;
abc_collection = db.collection("abc") ;
abc_collection.get()
.then( data => {
data.forEach(item => {
console.log(item.id , "=>", item.get('name')) ;
next_ref = item.get('next_ptr') ;
next_ref.get("name").then(item => {
console.log(item) ;
}).catch("") ;
} ) ;
}).catch("") ;

Answer 1

It looks like you're assuming that the query results contain all the referenced documents:
item.get('next_ptr')['name']
What item.get('next_ptr') returns is a DocumentReference object, not the entire contents of the document. You will have to query that document with its get() method in order to load its contents, or find the document using its ID in the results that you queried (if you guarantee that the reference always points to a document in the same collection.
You might just be better off storing the string ID of the document if you don't want to deal with the DocumentReference.