Read nested data from firebase realtime database in flutter - flutter

Question

If you see the screenshot of my database, the data is stored in a nested way (cartProduct is a key which has a value of an entire Json file with keys: "id", "price" etc.). In my code, I create a map of each record in the "Orders" table in order to retrieve key values of any key that I specify. This is done by specifying the key name in the databaseMapper variable.
I am trying to read the value of each "id" and store it in a list called "testerList". I am able to store each orderNum, totalAmount or any of those key values that I specify in the databaseMapper. However, if I specify ["id"] it does not work.
I did some research and saw that the only way to reference nested items in a map is by using the logic: databaseMapper["cartProduct"]["id"] like I did below, but I keep getting an error (see last screenshot).
Any help would be appreciated!
Future _readItemIDsTest() async {
//Stores each record in the table as a map
var snapshot = await _dbRef.child("Orders").get();
snapshot.children.forEach((childSnapshot) {
var databaseMapper = childSnapshot.value as Map;
testerList.addAll([databaseMapper["cartProduct"]["id"]]);
});
print(testerList);
}

Answer 1

Nvm, I figured it out. The code below solved my issue.
Future _readItemIDsTest() async {
//Stores each record in the table as a map
//Adds the itemName value of each item from the map
var snapshot = await _dbRef.child("Orders").get();
snapshot.children.forEach((childSnapshot) {
databaseMapper = childSnapshot.value as Map;
var cartProductList = databaseMapper["cartProduct"];
(cartProductList as List).forEach((cartProductElement) {
testerList.addAll([cartProductElement["id"]]);
});
});
print(testerList);
}