How can I store a Swift enum value in NSUserDefaults

Question

I have an enum like this:

enum Environment {
    case Production
    case Staging
    case Dev
}

And I\'d like to save an instance in NSUserDef

Answer 1

Using Codable protocol

Extent Environment enum that conforms to Codable protocol to encode and decode values as Data.

enum Environment: String, Codable {
    case Production
    case Staging
    case Dev
}

A wrapper for UserDefaults:

struct UserDefaultsManager {
    static var userDefaults: UserDefaults = .standard
    
    static func set(_ value: T, forKey: String) where T: Encodable {
        if let encoded = try? JSONEncoder().encode(value) {
            userDefaults.set(encoded, forKey: forKey)
        }
    }
    
    static func get(forKey: String) -> T? where T: Decodable {
        guard let data = userDefaults.value(forKey: forKey) as? Data,
            let decodedData = try? JSONDecoder().decode(T.self, from: data)
            else { return nil }
        return decodedData
    }
}

Usage

// Set
let environment: Environment = .Production
UserDefaultsManager.set(environment, forKey: "environment")

// Get
let environment: Environment? = UserDefaultsManager.get(forKey: "environment")