v1.2.0 (#47)

* [#38, #44] Added support for feature flag values in `UserDefaults` (#42, #46)
* [#37] Updated Copyright Year in `LICENSE`
* [#33, #35] Updated CI configuration (#34, #36)

.github/workflows/spm-ci.yml

@@ -10,6 +10,6 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Select Xcode version
-      run: sudo xcode-select -switch /Applications/Xcode_12.2.app
+      run: sudo xcode-select -switch /Applications/Xcode_12.5.app
     - name: Run tests
       run: swift test -v

LICENSE

@@ -186,7 +186,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright 2020 Yakov Manshin
+   Copyright © 2020–2021 Yakov Manshin
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

README.md

@@ -71,11 +71,9 @@ enum FeatureFlags {
 
     // `resolver` references one or more feature flag stores.
     // `MyFeatureFlagStore.shared` conforms to `FeatureFlagStoreProtocol`.
-    private static var resolver: FeatureFlagResolverProtocol = {
-        FeatureFlagResolver(configuration: .init(persistentStores: [
-            .opaque(MyFeatureFlagStore.shared)
-        ]))
-    }
+    private static var resolver = FeatureFlagResolver(configuration: .init(
+        persistentStores: [.opaque(MyFeatureFlagStore.shared)]
+    ))
 
     // Feature flags are initialized with three pieces of data:
     // a key string, the default value (used as fallback
@@ -118,6 +116,25 @@ To remove the override and revert to using values from persistent stores, you ca
 FeatureFlags.$promoEnabled.removeRuntimeOverride()
 ```
 
+### `UserDefaults`
+
+Since v1.2.0, you can use `UserDefaults` to read and write feature flag values. Just pass an instance of `UserDefaultsStore` as `runtimeStore` in `FeatureFlagResolverConfiguration`.
+
+For backward-compatibility reasons, **you can’t use `UserDefaultsStore` and the in-memory `RuntimeOverridesStore` at the same time**. But [it’ll get better in v2](https://github.com/yakovmanshin/YMFF/issues/41).
+
+```swift
+import Foundation
+
+// The `UserDefaultsStore` store must be both added in `persistentStores`
+// and, most importantly, set as the `runtimeStore`.
+private static var resolver = FeatureFlagResolver(configuration: .init(
+    persistentStores: [.userDefaults(UserDefaults.standard)],
+    runtimeStore: UserDefaultsStore()
+))
+```
+
+### More
+
 You can browse the source files to learn more about the options available to you. An extended documentation is coming later.
 
 ## Contributing

Sources/YMFF/FeatureFlagResolverImplementation/Store/FeatureFlagStore.swift

@@ -6,12 +6,20 @@
 //  Copyright © 2020 Yakov Manshin. See the LICENSE file for license info.
 //
 
+#if canImport(Foundation)
+import Foundation
+#endif
+
 // MARK: - FeatureFlagStore
 
 /// An object that provides a number of ways to supply the feature flag store.
 public enum FeatureFlagStore {
     case opaque(FeatureFlagStoreProtocol)
     case transparent(TransparentFeatureFlagStore)
+
+    #if canImport(Foundation)
+    case userDefaults(UserDefaults)
+    #endif
 }
 
 // MARK: - FeatureFlagStoreProtocol
@@ -24,6 +32,10 @@ extension FeatureFlagStore: FeatureFlagStoreProtocol {
             return store.value(forKey: key)
         case .transparent(let store):
             return store[key] as? Value
+        #if canImport(Foundation)
+        case .userDefaults(let userDefaults):
+            return userDefaults.object(forKey: key) as? Value
+        #endif
         }
     }
 

Sources/YMFF/FeatureFlagResolverImplementation/Store/UserDefaultsStore.swift

@@ -0,0 +1,48 @@
+//
+//  UserDefaultsStore.swift
+//  YMFF
+//
+//  Created by Yakov Manshin on 3/25/21.
+//  Copyright © 2021 Yakov Manshin. See the LICENSE file for license info.
+//
+
+#if canImport(Foundation)
+
+import Foundation
+
+// MARK: - UserDefaultsStore
+
+/// An object that provides read and write access to feature flag values store in `UserDefaults`.
+final public class UserDefaultsStore {
+
+    private let userDefaults: UserDefaults
+
+    /// Initializes a new `UserDefaultsStore`.
+    ///
+    /// - Parameter userDefaults: *Optional.* The `UserDefaults` object used to read and write values.
+    /// `UserDefaults.standard` is used by default.
+    public init(userDefaults: UserDefaults = .standard) {
+        self.userDefaults = userDefaults
+    }
+
+}
+
+// MARK: - MutableFeatureFlagStoreProtocol
+
+extension UserDefaultsStore: MutableFeatureFlagStoreProtocol {
+
+    public func value<Value>(forKey key: String) -> Value? {
+        userDefaults.value(forKey: key) as? Value
+    }
+
+    public func setValue<Value>(_ value: Value, forKey key: String) {
+        userDefaults.setValue(value, forKey: key)
+    }
+
+    public func removeValue(forKey key: String) {
+        userDefaults.removeObject(forKey: key)
+    }
+
+}
+
+#endif

Tests/YMFFTests/UserDefaultsStoreTests.swift

@@ -0,0 +1,66 @@
+//
+//  UserDefaultsStoreTests.swift
+//  YMFF
+//
+//  Created by Yakov Manshin on 3/21/21.
+//  Copyright © 2021 Yakov Manshin. See the LICENSE file for license info.
+//
+
+import XCTest
+@testable import YMFF
+
+final class UserDefaultsStoreTests: XCTestCase {
+
+    private var resolver: FeatureFlagResolver!
+
+    private lazy var userDefaults = UserDefaults()
+
+    override func setUp() {
+        super.setUp()
+
+        resolver = FeatureFlagResolver(configuration: .init(
+            persistentStores: [.userDefaults(userDefaults)],
+            runtimeStore: UserDefaultsStore(userDefaults: userDefaults)
+        ))
+    }
+
+}
+
+extension UserDefaultsStoreTests {
+
+    func testReadValueWithResolver() {
+        let key = "TEST_UserDefaults_key_123"
+        let value = 123
+
+        userDefaults.setValue(value, forKey: key)
+
+        // FIXME: [#40] Can't use `retrievedValue: Int?` here
+        let retrievedValue = try? resolver.value(for: key) as Int
+
+        XCTAssertEqual(retrievedValue, value)
+    }
+
+    func testWriteValueWithResolver() {
+        let key = "TEST_UserDefaults_key_456"
+        let value = 456
+
+        try? resolver.overrideInRuntime(key, with: value)
+
+        let retrievedValue = userDefaults.value(forKey: key) as? Int
+
+        XCTAssertEqual(retrievedValue, value)
+    }
+
+    func testWriteAndReadValueWithResolver() {
+        let key = "TEST_UserDefaults_key_789"
+        let value = 789
+
+        try? resolver.overrideInRuntime(key, with: value)
+
+        // FIXME: [#40] Can't use `retrievedValue: Int?` here
+        let retrievedValue = try? resolver.value(for: key) as Int
+
+        XCTAssertEqual(retrievedValue, value)
+    }
+
+}

Tests/YMFFTests/XCTestManifests.swift

@@ -53,11 +53,23 @@ extension RuntimeOverridesStoreTests {
     ]
 }
 
+extension UserDefaultsStoreTests {
+    // DO NOT MODIFY: This is autogenerated, use:
+    //   `swift test --generate-linuxmain`
+    // to regenerate.
+    static let __allTests__UserDefaultsStoreTests = [
+        ("testReadValueWithResolver", testReadValueWithResolver),
+        ("testWriteAndReadValueWithResolver", testWriteAndReadValueWithResolver),
+        ("testWriteValueWithResolver", testWriteValueWithResolver),
+    ]
+}
+
 public func __allTests() -> [XCTestCaseEntry] {
     return [
         testCase(FeatureFlagResolverTests.__allTests__FeatureFlagResolverTests),
         testCase(FeatureFlagTests.__allTests__FeatureFlagTests),
         testCase(RuntimeOverridesStoreTests.__allTests__RuntimeOverridesStoreTests),
+        testCase(UserDefaultsStoreTests.__allTests__UserDefaultsStoreTests),
     ]
 }
 #endif