FeatherQuill

Easily rollout your new features to segments of your audience.

Features

FeatherQuill is a Swift package that provides a mechanism for implementing offline feature flags in your application. Feature flags allow you to enable or disable features for different users or segments of your user base without requiring a server-side update. This can be useful for A/B testing, rollout strategies, and more.

Offline Support: Feature flags are stored locally on the device, so they can be used even when the device is not connected to the internet.
Audience Targeting: You can target feature flags to specific users or segments of users based on criteria such as user ID or device type.
SwiftUI Integration: Provides a Feature struct that integrates seamlessly with SwiftUI for easy feature access in your views.

Requirements

Apple Platforms

Xcode 15.3 or later
Swift 5.10 or later
iOS 17 / watchOS 10 / tvOS 17 / visionOS 1 / macCatalyst 17 / macOS 14 or later deployment targets

Linux

Ubuntu 20.04 or later
Swift 5.10 or later

Installation

To add the FeatherQuill package to your Xcode project, select File > Swift Packages > Add Package Dependency and enter the repository URL.

Using Swift Package Manager add the repository url:

dependencies: [
  .package(url: "https://github.com/brightdigit/FeatherQuill", from: "1.0.0-alpha.1")
]

Usage

FeatherQuill leverages protocols and generics for a flexible and type-safe experience. Here's a simplified example of how to define and use a feature:

// Define a user type (e.g., user roles)
public enum UserRole: UserType {
  case free
  case pro
  case admin

  public static var `default`: UserRole {
    return .free
  }
}

// Define a feature with a default value and targeting
struct MyFeature: FeatureFlag {
  static var audience: UserRole { .pro }
  static var probability: Double { 0.2 } // 20% chance of being enabled
  static var initialValue: Bool { false }
  static var options: AvailabilityOptions { .default }

  @Sendable
  static func evaluateUser(_ userType: UserRole) async -> Bool {
    // Optional: Implement custom user evaluation logic here
    return true
  }
}

extension EnvironmentValues {
  public var newDesignFeature: MyFeature.Feature { self[MyFeature.self] }
}

// Accessing the feature in a SwiftUI view
struct MyView: View {
  @Environment(\.myFeature) var myFeature

  var body: some View {
    if myFeature.isAvailable {
      Toggle("Is Enabled", isOn: myFeature.bindingValue)
    } else {
      Text("This feature is disabled.")
    }
  }
}

License

FeatherQuill is available under the MIT license. See the LICENSE file for more info.