How to write an array of values to Firestore with SwiftUI - swift

Question

Currently I have a screen that fetches a list of "items" from an "items" Collection. The user is supposed to be able to select multiple items, and add them to a document within the "Movies" collection when a button is pressed. I can't seem to figure out how to write the function to write the list of these items to the Movie document.
Code examples below
This is the loop that fetches the items (working so far)
let movie: Movie
#State var selections: [String] = []
#ObservedObject private var viewModel = ItemsViewModel()
#State private var isSelected = false
#State var movieID = ""
var body: some View {
VStack {
ForEach(viewModel.items.indices, id: \.self) { i in
Button(action: { viewModel.items[i].isSelected.toggle() }) {
HStack {
if viewModel.items[i].isSelected {
Text(viewModel.items[i].name)
.foregroundColor(.white)
.font(.system(size: 16, weight: .bold))
Spacer()
Image(systemName: "checkmark")
.foregroundColor(ColourManager.pinkColour)
.font(.system(size: 16))
} else {
Text(viewModel.items[i].name)
.foregroundColor(Color(.systemGray))
.font(.system(size: 16))
Spacer()
}
}
.padding(.vertical, 10)
.padding(.horizontal)
}
Divider()
}
}
.onAppear() {
self.viewModel.fetchData()
}
Button calling function
Button(action: { self.addItems() }) {
HStack {
Text("Add Selected Items")
}
Function to write to Firestore
func addItems() {
let db = Firestore.firestore()
db.collection("movies").document(self.movieID).setData(["item": [self.selections]])
}
What I would like is the Firestore db to look like:
{
movieID: 12345,
movieName: "Goodfellas",
items: [
item: "item 1",
item: "item 2"
]
}
So far I have the movieID and movieName working, just can't figure out how to record the selections and write them as items. Any help would be greatly appreciated!

Answer 1

The answer depends on what you'd like the type of items field to be. The information you want to store could be stored either as an array of strings or as an object literal. Using JSON:
// Array of String
items: ["item1", "item2"]
// Object Lieral
items: {
"key1": "item1",
"key2": "item2"
}
From the code posted the variable selections is already an array of strings, so the first option would be as simple as:
db.collection("movies").document(self.movieID).setData(["item": self.selections])
As for the second one, keep in mind that the keys of object literals must be unique so you'd need to derive these keys for each item somehow, construct the object and add it as the value of the document items key. For further reference on adding data in Swift check the documentation