Firestore Class 'QuerySnapshot' has no instance method '[]' - flutter

Question

I want a ListView to show the names of the users. I am using a cloudfunction with the admin sdk to return a list of all the users with the corresponding user IDs. When I want to pass that uid to a Widget with a streambuilder, it gives me the error:
Class 'QuerySnapshot' has no instance method '[]'.
Receiver: Instance of 'QuerySnapshot'
Tried calling: []("firstName")
This is the function I am calling while building the ListView for the title:
Widget getFirstName(uid, item) {
return StreamBuilder(
stream: Firestore.instance
.collection('users')
.document('HzBUMs06BAPHK0Y7m5kfOmUzawC2')
.collection('userInfo')
.snapshots(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (!snapshot.hasData) {
return Text('${item['email']}');
} else {
return Text('${snapshot.data.documents['firstName']}');
}
},
);
}
I am not using the uid which I will pass to it yet, as the User ID that I hardcoded right now is the only one with the firstName data in it.
When I feed it a non-existing userID, it still seems to think it has data in it and tries to return its (non-existent) data.
What am I doing wrong here?

Answer 1

I managed to fix it by using this piece of code:
Widget fullNameWidget(uid) {
return FutureBuilder(
future: fullName(uid),
builder: (context, snapshot) {
return Text('${snapshot.data}');
},
);
}
Future fullName(uid) async {
return Firestore.instance
.collection("users")
.document('$uid')
.collection("userInfo")
.getDocuments()
.then((querySnapshot) {
print(querySnapshot.documents[0]['firstName']);
if (querySnapshot == 'null') {
} else {
return '${querySnapshot.documents[0]['firstName']} ${querySnapshot.documents[0]['lastName']}';
}
// querySnapshot.documents.where((element) {
// print(element.documentID == 'firstName');
// });
});
}