ObservableDictionary.swift

import Observation

@Observable
final class ObservableDictionary<Key: Hashable, Value>  {
    @ObservationIgnored fileprivate var backingDictionary: Dictionary<Key, Value> = [:]
    
    public subscript(key: Key) -> Value? {
        get {
            let keyPath = \ObservableDictionary<Key, Value>.backingDictionary[key]
            access(keyPath: keyPath)
            return backingDictionary[key]
        }
        set {
            let keyPath = \ObservableDictionary<Key, Value>.backingDictionary[key]
            withMutation(keyPath: keyPath) {
                backingDictionary[key] = newValue
            }
        }
    }
}

extension ObservableDictionary: ExpressibleByDictionaryLiteral {
    convenience init(dictionaryLiteral elements: (Key, Value)...) {
        self.init()
        self.backingDictionary = Dictionary(uniqueKeysWithValues: elements)
    }
}