I’m developing an app for my school project and I stuck in an issue and I’m not able to handle it. I’m trying to get midTerm, finalTerm and lectureGradeId values from my Firebase Cloud Firestore. Except that values, I’m able to get every value from Firestore.

To make it clear, I’m putting my codes and my Firestore structure below:

Students.swift

import Foundation
import FirebaseFirestore

struct Grades: Codable, Hashable {
var lectureGradeId: String
var midTerm: String
var endTerm: String
}

struct Students: Identifiable, Codable {
var id: String
var email: String
var studentName: String
var studentSurname: String
var studentTerm: String
var studentBirthday: String
var studentClass: Int
var studentDept: String
var studentFaculty: String
var studentIsActive: Bool
var studentIsGraduated: Bool
var studentLectures: [String]?
var studentGrades: [Grades]?
}

StudentsViewModel.swift

import Foundation
import Firebase

class StudentsViewModel: ObservableObject {
@Published var students = [Students]()

private var db = Firestore.firestore()

func fetchData() {
    db.collection("Students").whereField("id", isEqualTo: "20704029").addSnapshotListener { querySnapshot, error in
        guard let documents = querySnapshot?.documents else {
            print("No documents")
            return
        }
        
        self.students = documents.map { (queryDocumentSnapshot) -> Students in
            let data = queryDocumentSnapshot.data()
            
            let id = data["id"] as? String ?? ""
            let email = data["email"] as? String ?? ""
            let studentName = data["studentName"] as? String ?? ""
            let studentSurname = data["studentSurname"] as? String ?? ""
            let studentTerm = data["studentTerm"] as? String ?? ""
            let studentBirthday = data["studentBirthday"] as? String ?? ""
            let studentClass = data["studentClass"] as? Int ?? 0
            let studentDept = data["studentDept"] as? String ?? ""
            let studentFaculty = data["studentFaculty"] as? String ?? ""
            let studentIsActive = data["studentIsActive"] as? Bool ?? true
            let studentIsGraduated = data["studentIsGraduated"] as? Bool ?? false
            let studentLectures = data["studentLectures"] as? Array ?? [""]
            
            let student = Students(id: id, email: email, studentName: studentName, studentSurname: studentSurname, studentTerm: studentTerm, studentBirthday: studentBirthday, studentClass: studentClass, studentDept: studentDept, studentFaculty: studentFaculty, studentIsActive: studentIsActive, studentIsGraduated: studentIsGraduated, studentLectures: studentLectures)
            //print(student)
            return student
        }
    }
}
}

GradesPage.swift

import SwiftUI

struct GradesPage: View {

@ObservedObject private var viewModel = StudentsViewModel()

var body: some View {
    NavigationView {
        List(viewModel.students) { student in
            VStack(alignment: .leading) {
                Text("Student Name: ") + Text(" ") + Text(student.studentName) + Text(" ") + Text(student.studentSurname)
                //I want to add the grades to see in here but don't know how to handle it
            }
        }
    }.onAppear {
        self.viewModel.fetchData()
    }
}
}

Firestore Structure:

Solutions that I tried:

Peter Friese Documentation

Firestore Official Documentation

Thanks in advance, all helps are welcome!