UserStorage

A lightweight Swift package for persistent key-value storage — powered by CoreData. Unlike UserDefaults, which is limited to property list types (String, Int, Bool, Data, Date, Array, Dictionary), UserStorage can persist any Codable type, including custom structs and enums, in a thread-safe SQLite-backed store.

It also ships with @PublishedUserStorage, a property wrapper that works like @AppStorage — but isn't limited to SwiftUI views and supports any Codable type.

Why not just UserDefaults?

	UserDefaults	UserStorage
Supported types	Property list types only	Any Codable type
Storage backend	plist file	SQLite (CoreData)
Thread safety	Not guaranteed	performAndWait on background contexts
SwiftUI integration	@AppStorage (views only)	@PublishedUserStorage (anywhere)
Custom structs/enums	Manual serialization needed	Works out of the box

Installation

Add UserStorage to your Package.swift:

.package(url: "https://github.com/smart-byte/UserStorage.git", from: "0.2.0")

Then import it:

import UserStorage

Usage

Storing and Retrieving Data

import UserStorage

// Store a value
UserStorage.shared.save("Hello, UserStorage!", forKey: "greeting")

// Retrieve the value
if let greeting: String = UserStorage.shared.load(forKey: "greeting") {
    print(greeting) // Output: Hello, UserStorage!
}

// Works with any Codable type
struct UserProfile: Codable {
    var name: String
    var age: Int
    var tags: [String]
}

let profile = UserProfile(name: "Mario", age: 30, tags: ["swift", "ios"])
UserStorage.shared.save(profile, forKey: "profile")

let loaded: UserProfile? = UserStorage.shared.load(forKey: "profile")

Using @PublishedUserStorage

@PublishedUserStorage is a property wrapper that combines the persistence of @AppStorage with the reactivity of @Published. It can be used in any ObservableObject — not just SwiftUI views.

import SwiftUI
import UserStorage

class UserSettingsModel: ObservableObject {
    @PublishedUserStorage("username")
    var username = "none"

    @PublishedUserStorage("appTheme")
    var appTheme = AppTheme.light

    @PublishedUserStorage("isFirstLaunch")
    var isFirstLaunch = true

    enum AppTheme: String, Codable {
        case light
        case dark
    }
    
    init() {
        // Required: connect property wrapper publishers to ObservableObject
        let mirror = Mirror(reflecting: self)
        mirror.children.forEach { child in
            if let observedProperty = child.value as? PublishedUserStorageWrapper {
                observedProperty.objectWillChange = self.objectWillChange
            }
        }
    }
}

Then use it in your app like any other ObservableObject:

@main
struct ExampleApp: App {
    @StateObject var userSettings = UserSettingsModel()

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(userSettings)
        }
    }
}

struct ContentView: View {
    @EnvironmentObject var userSettings: UserSettingsModel

    var body: some View {
        VStack {
            Text("Hello, \(userSettings.username)!")
            Button(action: {
                userSettings.username = "User"
            }) {
                Text("Change Username")
            }
        }
    }
}

License

MIT — see LICENSE for details.