⚡ Bolt: Consolidate array iterations in CategoryFilterWidget

.jules/bolt.md

@@ -5,3 +5,6 @@
 ## 2025-03-09 - Replace .map() with point updates for React state arrays
 **Learning:** For updating single items in small React state arrays (e.g., layout configurations or task lists), using `array.map()` introduces significant performance overhead by iterating through the entire array and calling the callback for every element. This causes unnecessary processing.
 **Action:** Prefer "point updates" using `findIndex` and array spreading over `array.map()`. This minimizes object allocations and improves fluidity, especially on lower-power devices.
+## 2026-05-20 - Consolidating multiple array iterations in React useMemo hooks
+**Learning:** When deriving multiple unique sets of data from a single source array (e.g., categories and profiles from a shortcuts list), chaining array methods like `.map()`, `.flatMap()`, and creating separate `useMemo` hooks leads to redundant iterations and intermediate array allocations. In large datasets, this overhead scales linearly per derived array.
+**Action:** Consolidate these calculations into a single `useMemo` hook using a single `for...of` loop to populate multiple `Set`s simultaneously. This pattern minimizes iterations, reduces memory pressure, and is significantly faster than multiple chained methods.

components/CategoryFilterWidget.tsx

@@ -6,12 +6,23 @@ import { UsersIcon } from '@heroicons/react/24/outline';
 export const CategoryFilterWidget: React.FC = () => {
   const { shortcuts, filterCategory, setFilterCategory, filterProfile, setFilterProfile } = useGTab();
 
-  const activeCategories = useMemo(() => {
-    return ['All', ...new Set(shortcuts.map(s => s.category))];
-  }, [shortcuts]);
+  const { activeCategories, uniqueProfiles } = useMemo(() => {
+    const catSet = new Set<string>();
+    const profSet = new Set<string>();
+
+    for (const s of shortcuts) {
+      if (s.category) catSet.add(s.category);
+      if (s.profiles) {
+        for (const p of s.profiles) {
+          if (p.name) profSet.add(p.name);
+        }
+      }
+    }
 
-  const uniqueProfiles = useMemo(() => {
-    return Array.from(new Set(shortcuts.flatMap(s => s.profiles?.map(p => p.name) || []))).sort();
+    return {
+      activeCategories: ['All', ...catSet],
+      uniqueProfiles: Array.from(profSet).sort()
+    };
   }, [shortcuts]);
 
   return (