From 9691a7cc46b2687eaf5e7f9119ebe2b0a79c2b41 Mon Sep 17 00:00:00 2001
From: Sindre Sorhus <sindresorhus@gmail.com>
Date: Fri, 18 Jun 2021 13:15:13 +0700
Subject: [PATCH] Add `.defaultValue` and `.isDefaultValue` to `@Default` (#76)

---
 Sources/Defaults/SwiftUI.swift                 | 9 +++++++++
 Tests/DefaultsTests/DefaultsSwiftUITests.swift | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/Sources/Defaults/SwiftUI.swift b/Sources/Defaults/SwiftUI.swift
index 8a7b219..bec3503 100644
--- a/Sources/Defaults/SwiftUI.swift
+++ b/Sources/Defaults/SwiftUI.swift
@@ -87,6 +87,9 @@ public struct Default<Value: Defaults.Serializable>: DynamicProperty {
 
 	public var projectedValue: Binding<Value> { $observable.value }
 
+	/// The default value of the key.
+	public var defaultValue: Value { key.defaultValue }
+
 	/// Combine publisher that publishes values when the `Defaults` item changes.
 	public var publisher: Publisher { Defaults.publisher(key) }
 
@@ -118,6 +121,12 @@ public struct Default<Value: Defaults.Serializable>: DynamicProperty {
 	}
 }
 
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension Default where Value: Equatable {
+	/// Indicates whether the value is the same as the default value.
+	public var isDefaultValue: Bool { wrappedValue == defaultValue }
+}
+
 @available(macOS 11, iOS 14, tvOS 14, watchOS 7, *)
 extension Defaults {
 	/**
diff --git a/Tests/DefaultsTests/DefaultsSwiftUITests.swift b/Tests/DefaultsTests/DefaultsSwiftUITests.swift
index 4e1ace5..987c27f 100644
--- a/Tests/DefaultsTests/DefaultsSwiftUITests.swift
+++ b/Tests/DefaultsTests/DefaultsSwiftUITests.swift
@@ -44,5 +44,7 @@ final class DefaultsSwiftUITests: XCTestCase {
 		XCTAssertTrue(view.hasUnicorn)
 		XCTAssertEqual(view.user.username, "Chen")
 		XCTAssertEqual(view.setInt, Set(1...4))
+		XCTAssertFalse(Default(.hasUnicorn).defaultValue)
+		XCTAssertFalse(Default(.hasUnicorn).isDefaultValue)
 	}
 }