IDedViewModel can use a cache

Author: anconaesselmann

Sources/LoadableView/Protocols/LoadableView/IDedLoadableViewModel.swift

@@ -18,6 +18,8 @@ public protocol IDedLoadableViewModel: BaseLoadableViewModel {
 
     // MARK: - Optional implementation
     func cancel(id: ID) async
+
+    var cache: (any ViewDataCache<ID, Element>)? { get }
 }
 
 public extension IDedLoadableViewModel {
@@ -26,6 +28,10 @@ public extension IDedLoadableViewModel {
         // Implement to cancel loading
     }
 
+    var cache: (any ViewDataCache<ID, Element>)? {
+        return nil
+    }
+
     func cancel() async {
         guard let id = self.id else {
             assertionFailure("No ID")
@@ -60,9 +66,14 @@ public extension IDedLoadableViewModel {
             guard case .notLoaded = viewState else {
                 return
             }
-            setIsLoading(true)
+            if let cache, let cached = cache.value(forKey: id) {
+                viewState = .loaded(cached)
+            } else {
+                setIsLoading(true)
+            }
             self.id = id
             let item = try await load(id: id)
+            cache?.insert(item, forKey: id)
             if let reloadsWhenForegrounding = self as? (any ReloadsWhenForegrounding) {
                 reloadsWhenForegrounding.setLastLoaded()
             }

Sources/LoadableView/Protocols/ViewDataCache.swift

@@ -0,0 +1,13 @@
+//  Created by Axel Ancona Esselmann on 11/20/24.
+//
+
+import Foundation
+
+public protocol ViewDataCache<Key, Value> {
+    associatedtype Key
+        where Key: Hashable
+    associatedtype Value
+
+    func insert(_ value: Value, forKey key: Key)
+    func value(forKey key: Key) -> Value?
+}