Add Once condition

Sources/OnboardingKit/Documentation.docc/Extensions/OnboardingConditions.md

@@ -6,6 +6,8 @@
 
 - ``ColdLaunch``
 - ``ManualCounter``
+- ``Once``
 - ``TimeSinceFirstLaunch``
 - ``AfterDate``
+- ``Conjunction``
 - ``Disjunction``

Sources/OnboardingKit/Documentation.docc/OnboardingKit.md

@@ -10,7 +10,7 @@ The top-level component of OnboardingKit is ``OnboardingManager``. Typically, yo
 
 An ``OnboardingManager`` instance contains a collection of onboarding events, which are represented as instances of the ``OnboardingEvent`` class. Each ``OnboardingEvent`` instance represents a particular event that might occur as the user uses your app. When an onboarding event occurs, OnboardingKit can notify your app in one of two ways: it can set a property on a ”flags” object (*i.e.*, an instance of a class that conforms to the ``OnboardingFlags`` protocol) that you specify, or it can just call a handler function that you provide.
 
-Each onboarding event contains a collection of onboarding conditions, which are structures that conform to the ``OnboardingCondition`` protocol. An event is triggered when **all** of its conditions are satisfied. All of the built-in conditions are contained in the ``OnboardingConditions`` namespace. To enable more dynamic onboarding flows, OnboardingKit provides a special ``OnboardingConditions/Disjunction`` condition that’s satisfied when **any** of its child conditions are satified.
+Each onboarding event contains a collection of onboarding conditions, which are structures that conform to the ``OnboardingCondition`` protocol. An event is triggered when **all** of its conditions are satisfied. All of the built-in conditions are contained in the ``OnboardingConditions`` namespace. To enable more dynamic onboarding flows, OnboardingKit provides a special ``OnboardingConditions/Disjunction`` condition that’s satisfied when **any** of its child conditions are satified as well as an ``OnboardingConditions/Conjunction`` condition that’s satisfied when **all** of its child conditions are satisfied, which is useful for nesting inside of a disjunction condition.
 
 Events must be intentionally checked to see if they have been triggered; OnboardingKit won’t update your UI unless some event is checked and determined to have occured. Currently, OnboardingKit provides two ways to check events: it can check them automatically every time your app launches, and it can check them when you manually call ``OnboardingManager/checkManually()``. Each event automatically determines the manner in which it’s checked, so it’s a good idea to call ``OnboardingManager/checkManually()`` whenever you think that an onboarding event could possibly have occured. More automated ways to check events may be added in the future.
 

Sources/OnboardingKit/OnboardingCondition.swift

@@ -163,6 +163,33 @@ public enum OnboardingConditions {
 
  }
 
+ /// A condition that’s satisfied on the first cold launch and never again.
+ public struct Once: OnboardingCondition {
+
+ public static var triggers: Set<OnboardingTrigger> = [.launch]
+
+ public var isSatisfied: Bool {
+ get {
+ if UserDefaults.standard.bool(forKey: self.defaultsKey) {
+ return false
+ } else {
+ UserDefaults.standard.set(true, forKey: self.defaultsKey)
+ return true
+ }
+ }
+ }
+
+ /// The key that’s used to store the Boolean flag for this condition with `UserDefaults`.
+ public let defaultsKey: String
+
+ /// Creates a “once” condition.
+ /// - Parameter defaultsKey: The key that’s used to store the Boolean flag for this condition with `UserDefaults`.
+ public init(defaultsKey: String) {
+ self.defaultsKey = defaultsKey
+ }
+
+ }
+
  /// A condition that checks how much time has passed since the first launch.
  @available(iOS 15, macOS 12, watchOS 8, tvOS 15, *) public struct TimeSinceFirstLaunch: RegistrableOnboardingCondition {