Hi everyone !

I'm trying to save a custom object into the UserDefaults but it sounds like the JSONEncoder don't encode correctly my object. Take a look at my object structure:

struct Language: Identifiable, Codable {
    @DocumentID var id: String?
    var code: String
    var localizedName: String? {
        return localizedStringFromCode()
    }

    init?(id: String?, code: String?) {
        guard let code = code else { return nil }
        self.id = id
        self.code = code
    }

    private func localizedStringFromCode() -> String? {
        return Locale.current.localizedString(forLanguageCode: self.code)
    }
}

To encode this object, I just followed the example here

Here is how I try to encode my custom object:

var sourceLanguage: Language? {
        set {
            if let value = newValue {
      // The if let below fails due to encode failure
                if let encodedLanguage = try? encoder.encode(value) {
                    UserDefaults.standard.set(encodedLanguage, forKey: "SourceLanguage")
                }
            }
        }

        get {
            if let savedLanguage = UserDefaults.standard.object(forKey: "SourceLanguage") as? Data,
               let loadedLanguage = try? decoder.decode(Language.self, from: savedLanguage) {
                return loadedLanguage
            } else {
                return nil
            }
        }
    }

I thanks you a lot in advance and I hope you'll help me solve my problem. Have a nice day !

What is the encoding error you're getting?

I'm not getting any error because I do "if let". But this line:

try? encoder.encode(value)

returns nil.

Apparently, the encoder failed to encode my value. I wonder if the problem is about my object structure or something else.

Thanks a lot !

Instead of masking the error with try? do this:

do {
    let encodedLanguage = try encoder.encode(value)
    UserDefaults.standard.set(encodedLanguage, forKey: "SourceLanguage")
}
catch {
    print(error)
}

That will let you see what the error is. It's hard to know how to correct it if you don't know what's going wrong.

Thank you for the tip ! Here is the error:

("DocumentID values can only be encoded with Firestore.Encoder")

This is because I use Firebase Firestore. So I think I will have to implement customs encoder and decoder initializers. Do you confirm ?

I've never worked with Firestore so I can't say.

Maybe this would be useful: Mapping Firestore Data in Swift - The Comprehensive Guide