Firestore - appending data to a single value inside a struct - arrays

Question

How can I update a single value inside of a struct. Currently I'm fetching all of the data inside multiple documents of a collection with the below function. the data structure is as follows:
People - collection
DocumentID
Name: "Joe"
Friends (Object)
1 (Object)
Name: "Sally"
2 (Object)
Name: "Sam"
DocumentID
Name: "Emily"
Friends (Object)
1 (Object)
Name: "Peter".
If I run the below code it jut creates a new array, whereas I would like to merge the two together. Any help is greatly appreciated. Many thanks!!
func loadData() {
let userRef = db.collection("Users").document(user!)
let docRef = userRef.collection("People")
docRef.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
if let snapshot = querySnapshot {
for document in snapshot.documents {
let data = document.data()
let name = data["name"] as? String ?? ""
let newPeople = People(name: name, friends: [:])
self.peopleArray.append(newPeople)
if let friends = data["Friends"] as? [String: Any] {
for (key, _) in friends {
let number = friends[key] as? [String: Any] ?? [:]
let friendsName = number["name"] as? String ?? ""
\\ The code in which I want to update the value of friendsName into the previous set array
let newFriends = People(name: name, friendsName: friendsName)
self.peopleArray.append(newFriends)
}
}
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
}
}
}
}
What I would like the array to look like:
[ name: Joe, friends: ["name": Sally, "name": Sam]], [name: Emily, friends: [name: Peter]]
Updated Code
var friendsName: [String: [String: Int]] = [:]
var friendsArray = [String: Int]()
func loadData() {
let userRef = db.collection("Users").document(user!)
let docRef = userRef.collection("People")
docRef.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
if let snapshot = querySnapshot {
for document in snapshot.documents {
let data = document.data()
let name = data["name"] as? String ?? ""
if let friends = data["Friends"] as? [String: Any] {
for friend in friends {
let key = friend.key
let values = friend.value
let friendsDict = friends[key] as? [String: Any] ?? [:]
let friendsNameString = friendsDict["name"] as? String ?? ""
self.friendsArray.updateValue(friendsNameString, forKey: key)
}
self.friendsName.updateValue(self.friendsArray, forKey: "name")
let newPeople = People(name: name, friends: self.friendsName)
self.peopleArray.append(newPeople)
self.friendsArray.removeAll()
self.friendsName.removeAll()
}
}
}
}
}
}

Answer 1

The way you are doing it seems a little too complex to what you require. Firestore has quite fast queries so you can have different collections for people and friends.
Lets say for example that in your "people" collection you have the names of all the users and other properties that you may need... Email, age, gender, etc etc.
Then in a second collection you can add the relations for each user. For example, "Friends" contains documents with fields friendA: AAA, FriendB: BBB. Then you won't have any duplicates in your data.
The way you are doing it creates too many duplicated that you don't need. For example, in your Joe document you have set that Sally is a friend. But then in your Sally document you will have to set that Joe is a friend. This makes the database more difficult to maintain and with a lot of duplicates.
If you make two different collections for People and Friends the code for fetching also becomes simpler.