类型 'Favorites.Type' 不能符合 'Encodable'； 只有结构/枚举/类类型可以符合协议

Question

Please tell me what could be the problem with this error and how to fix it?

I'm use SwiftUI 2.0

"Type 'Favorites.Type' cannot conform to 'Encodable'; only struct/enum/class types can conform to protocols"

Code:

class Favorites: ObservableObject {

private var tasks: Set<String>
let defaults = UserDefaults.standard

init() {
    let decoder = JSONDecoder()
    if let data = defaults.value(forKey: "Favorites") as? Data {
        let taskData = try? decoder.decode(Set<String>.self, from: data)
        self.tasks = taskData ?? []
    } else {
        self.tasks = []
    }
}

func getTaskIds() -> Set<String> {
    return self.tasks
}

func isEmpty() -> Bool {
    tasks.count < 1
}

func contains(_ task: dataTypeFont) -> Bool {
    tasks.contains(task.id)
}

func add(_ task: dataTypeFont) {
    objectWillChange.send()
    tasks.insert(task.id)
    save()
}

func remove(_ task: dataTypeFont) {
    objectWillChange.send()
    tasks.remove(task.id)
    save()
}

func save() {
    let encoder = JSONEncoder()
    if let encoded = try? encoder.encode(Favorites)  {
        defaults.set(encoded, forKey: "Favorites")
    }
}

}

Screenshot Error: Error

Answer 1

Typo.

According to the load method you have to encode tasks not the class type

func save() {
    let encoder = JSONEncoder()
    if let encoded = try? encoder.encode(tasks)  {
        defaults.set(encoded, forKey: "Favorites")
    }
}

And don't use value(forKey: with UserDefaults , there is a dedicated method

if let data = defaults.data(forKey: "Favorites") {