⚡ Bolt: Prevent intermediate array allocations in CacheoutViewModel

.jules/bolt.md

@@ -32,3 +32,6 @@
 ## 2024-05-30 - SwiftUI ForEach and Lazy Collections
 **Learning:** In SwiftUI, avoid using `.lazy.filter` directly inside a `ForEach` loop, as `ForEach` requires the data to conform to `RandomAccessCollection`, which `LazyFilterSequence` does not. Eagerly compute the filtered array before passing it to the `ForEach` view builder.
 **Action:** When optimizing SwiftUI views, only apply `.lazy.filter` to properties where you immediately consume the sequence (e.g., calling `.count`, `.reduce`, or `.sorted()`). For data bound to a `ForEach` list, continue using standard eager `.filter`.
+## 2024-05-30 - Short-circuiting Computed Properties in SwiftUI
+**Learning:** In SwiftUI ViewModels, calculating boolean properties (like `hasSelection`) eagerly allocated intermediate arrays and evaluated entire sums just to check for emptiness (`!array.filter(...).isEmpty` or `array.reduce(...) > 0`). This causes unnecessary memory churn and O(N) CPU operations during frequent redraws.
+**Action:** Replace eager array filtering and full map reductions with `.contains(where:)` to allow short-circuit evaluation. This changes the complexity from O(N) to an O(1) best-case, skipping full traversal as soon as the first match is found.

Sources/Cacheout/ViewModels/CacheoutViewModel.swift

@@ -106,7 +106,8 @@ class CacheoutViewModel: ObservableObject {
     }
 
     var selectedSize: Int64 {
-        selectedResults.reduce(0) { $0 + $1.sizeBytes }
+        // ⚡ Bolt: Use .lazy.filter to avoid allocating an intermediate array
+        scanResults.lazy.filter(\.isSelected).reduce(0) { $0 + $1.sizeBytes }
     }
 
     var formattedSelectedSize: String {
@@ -118,7 +119,11 @@ class CacheoutViewModel: ObservableObject {
     }
 
     var hasResults: Bool { !scanResults.isEmpty || !nodeModulesItems.isEmpty }
-    var hasSelection: Bool { !selectedResults.isEmpty || selectedNodeModulesSize > 0 }
+
+    // ⚡ Bolt: Use .contains(where:) to allow short-circuit evaluation and avoid full array allocations/reductions
+    var hasSelection: Bool {
+        scanResults.contains(where: \.isSelected) || nodeModulesItems.contains(where: \.isSelected)
+    }
 
     // MARK: - Node Modules computed properties