Swift: Downcasting a Binding within a List while retaining link - swift

Question

I have the following view code (unworking):
import SwiftUI
struct SearchFilterView: View {
#Binding var filters: [any SourceFilter]
var body: some View {
List($filters, id: \.id) { filter in
switch filter.wrappedValue {
case var textFilter as SourceTextFilter:
TextField(
textFilter.name,
text: Binding(get: { textFilter.value }, set: { textFilter.value = $0 })
)
case var toggleFilter as SourceToggleFilter:
Toggle(
toggleFilter.name,
isOn: Binding(get: { toggleFilter.value }, set: { toggleFilter.value = $0 })
)
case var segmentFilter as SourceSegmentFilter:
Picker(
segmentFilter.name,
selection: Binding(get: { segmentFilter.value }, set: { segmentFilter.value = $0 })
) {
ForEach(segmentFilter.selections, id: \.self) { selection in
Text(selection).tag(selection)
}
}.pickerStyle(.segmented)
default:
EmptyView()
}
}
}
}
The code above compiles, but even though the values change for each filter, as soon as the view reloads, all of the changes are lost. The code for the SourceFilters are below.
protocol JSObjectEncodable {
var object: [String: Any] { get }
}
protocol JSObjectDecodable {
init?(from object: [String: Any])
}
protocol JSObjectCodable: JSObjectDecodable, JSObjectEncodable {}
protocol SourceFilter<ValueType>: JSObjectCodable, Sendable {
associatedtype ValueType
var id: String { get }
var value: ValueType { get set }
var name: String { get }
}
struct SourceTextFilter: SourceFilter {
init?(from object: [String: Any]) {
guard let id = object["id"] as? String,
let value = object["value"] as? String,
let name = object["name"] as? String else { return nil }
self.id = id
self.value = value
self.name = name
}
let id: String
var value: String
let name: String
var object: [String: Any] {
[
"id": id,
"value": value,
"name": name
]
}
}
struct SourceToggleFilter: SourceFilter {
init?(from object: [String: Any]) {
guard let id = object["id"] as? String,
let value = object["value"] as? Bool,
let name = object["name"] as? String else { return nil }
self.id = id
self.value = value
self.name = name
}
let id: String
var value: Bool
let name: String
var object: [String: Any] {
[
"id": id,
"value": value,
"name": name
]
}
}
struct SourceSegmentFilter: SourceFilter {
init?(from object: [String: Any]) {
guard let id = object["id"] as? String,
let value = object["value"] as? String,
let name = object["name"] as? String,
let selections = object["selections"] as? [String] else { return nil }
self.id = id
self.value = value
self.name = name
self.selections = selections
}
let id: String
var value: String
let name: String
let selections: [String]
var object: [String: Any] {
[
"id": id,
"value": value,
"name": name,
"selections": selections
]
}
}
How do I have it so that my changes to the filter values are saved, even after being downcast to their respective filter type? Thanks in advance.