⚡ Bolt: Optimize selection checks to avoid eager array allocations and forced iteration

.jules/bolt.md

@@ -28,3 +28,6 @@
 ## 2025-10-24 - Bulk Disk I/O Parallelization and Thread Pool Starvation
 **Learning:** Both `withTaskGroup` and `Task.detached` schedule their work on Swift's cooperative thread pool, which has only as many threads as the CPU has cores. Running synchronous blocking I/O (like `FileManager.removeItem`) directly inside such tasks ties up cooperative threads — when every thread is parked in a syscall there is nothing left to advance other Swift Concurrency work, which manifests as starvation and (with self-referential `await` chains) outright deadlock. `Task.detached` does not help here: "detached" means unstructured/independent, not "off the cooperative pool."
 **Action:** To parallelize bulk blocking I/O, combine a sliding-window `withThrowingTaskGroup` (e.g., `maxConcurrency` of 8) with a per-item handoff to a GCD queue: wrap the blocking call in `withCheckedThrowingContinuation` and dispatch it via `DispatchQueue.global(qos: .userInitiated).async { ... continuation.resume(...) }`. The cooperative-pool task only `await`s the continuation, so it never holds a thread while the syscall runs.
+## 2025-11-01 - Short-Circuit Evaluation and Eager Filtering
+**Learning:** In Swift, checking `.isEmpty` on a property that returns a filtered array (e.g., `array.filter { ... }`) or computing a sum to check if it's greater than 0 will eagerly process the entire collection and allocate intermediate arrays, causing unnecessary memory churn and CPU overhead.
+**Action:** Always use `.contains(where: condition)` instead of `.filter { condition }.isEmpty` to allow short-circuit evaluation and prevent intermediate array allocations. Use `.lazy.filter` before `.reduce` to avoid creating intermediate arrays when a full sum is required.

Sources/Cacheout/ViewModels/CacheoutViewModel.swift

@@ -106,7 +106,8 @@ class CacheoutViewModel: ObservableObject {
     }
 
     var selectedSize: Int64 {
-        selectedResults.reduce(0) { $0 + $1.sizeBytes }
+        // ⚡ Bolt Optimization: Chain .lazy.filter before .reduce to avoid intermediate array allocation
+        scanResults.lazy.filter(\.isSelected).reduce(0) { $0 + $1.sizeBytes }
     }
 
     var formattedSelectedSize: String {
@@ -118,7 +119,10 @@ class CacheoutViewModel: ObservableObject {
     }
 
     var hasResults: Bool { !scanResults.isEmpty || !nodeModulesItems.isEmpty }
-    var hasSelection: Bool { !selectedResults.isEmpty || selectedNodeModulesSize > 0 }
+    var hasSelection: Bool {
+        // ⚡ Bolt Optimization: Use contains(where:) to short-circuit instead of eagerly filtering arrays or summing sizes
+        scanResults.contains(where: \.isSelected) || nodeModulesItems.contains(where: \.isSelected)
+    }
 
     // MARK: - Node Modules computed properties