Merge pull request #454 from rusik/patch-1

Update 10160.md

content/notes/wwdc23/10160.md

@@ -1,5 +1,5 @@
 ---
-contributors: RamitSharma991
+contributors: RamitSharma991, rusik
 ---
 
 * SwiftUI makes it easy to build complex, powerful apps, offering a large set of features and complex controls like lists and tables.
@@ -35,23 +35,24 @@ contributors: RamitSharma991
 
 ```swift
 struct ScalableDogImage: View {
-	@State private var scaleToFill = false
-	var dog: Dog
-	
-	var body: some View {
-      let _ = Self._printChanges()
-    // it is never guaranteed to always exist and may even be removed in a future release,
+  @State private var scaleToFill = false
+  var dog: Dog
+
+  var body: some View {
+
+    // It is never guaranteed to always exist and may even be removed in a future release,
     // so never submit a call to this method to the app store.
-		dog.image
-			.resizable()
-			.aspectRatio(
-				contentMode: scaleToFill ? .fill : .fit)
-			.frame(maxHeight: scaleToFill ? 500 : nil)
-			.padding(.vertical, 16)
-			.onTapGesture {
-				withAnimation { scaleToFill.toggle() }
-			}
-	}
+    let _ = Self._printChanges()
+
+    dog.image
+      .resizable()
+      .aspectRatio(contentMode: scaleToFill ? .fill : .fit)
+      .frame(maxHeight: scaleToFill ? 500 : nil)
+      .padding(.vertical, 16)
+      .onTapGesture {
+        withAnimation { scaleToFill.toggle() }
+      }
+  }
 }
 ```
 
@@ -81,46 +82,45 @@ struct ScalableDogImage: View {
 // which brings us to the initializer, which fetches the list of dogs.
 // As the code comment says, this could take a long time. This is synchronous work.
 struct DogRootView: View {
-	@State private var model = FetchModel()
-	
-	var body: some View {
-		DogList(model.dogs)
-	}
+  @State private var model = FetchModel()
+    
+  var body: some View {
+      DogList(model.dogs)
+  }
 }
 
 @Observable class FetchModel {
-	var dogs: [Dog]
-	
-	init() {
-		fetchDogs()
-	}
+  var dogs: [Dog]
+    
+  init() {
+      fetchDogs()
+  }
 }
-	
-	func fetchDogs() {
-		// Takes a long time
-	}
+    
+  func fetchDogs() {
+    // Takes a long time
+  }
 }
 
-//// Updated and fixed using task modifier, asynchronous fetch and awaiting.
-    struct DogRootView: View {
-	@State private var model = FetchModel()
-	
-	var body: some View {
-		DogList(model.dogs)
-			.task { await model.fetchDogs() }
-	}
+// Updated and fixed using task modifier, asynchronous fetch and awaiting.
+struct DogRootView: View {
+  @State private var model = FetchModel()
+    
+  var body: some View {
+    DogList(model.dogs)
+      .task { await model.fetchDogs() }
+  }
 }
 
 @Observable class FetchModel {
-	var dogs: [Dog]
-	
-	init() {}
-	
-	func fetchDogs() async {
-		// Takes a long time
-	}
+  var dogs: [Dog]
+    
+  init() {}
+    
+  func fetchDogs() async {
+    // Takes a long time
+  }
 }
-
 ```
 
 ## Other hidden sources of work
@@ -160,19 +160,41 @@ struct DogRootView: View {
 
 ```swift
 
-// Lists
-// unknown views per element
-  List {
-	ForEach(dogs) {
-		DogCell(dog: $0)
-	}
+// Constant views per element - ✅
+List {
+  ForEach(dogs) { dog in
+    DogCell(dog)
+  }
+}
+
+// Variable views per element - ⚠️
+List {
+  ForEach(dogs) { dog in
+    if dog.fetchToy == .ball {
+      DogCell(dog)
+    }
+  }
+}
+
+// Unknown views per element - ⚠️
+List {
+  ForEach(dogs) { dog in
+    AnyView(...)
+  }
+}
+
+// Avoid inline filtering - ⚠️
+List {
+  ForEach(dogs.filter(...)) { dog in
+    DogCell(dog)
+  }
 }
 
-// Lists Fixed with cached filter and constant views per element
-  List {
-	ForEach(tennisBallDogs) { dog in
-		DogCell(dog)
-	}
+// Cached filter and constant views per element - ✅
+List {
+  ForEach(tennisBallDogs) { dog in
+    DogCell(dog)
+  }
 }
 ```