perf: wrap admin-page.tsx filtering logic in useMemo

Co-authored-by: KxlSys <116387953+KxlSys@users.noreply.github.com>

Author: google-labs-jules[bot]

.jules/bolt.md

@@ -21,3 +21,6 @@
 ## 2024-07-10 - O(n) Single Pass Data Aggregation
 **Learning:** Using chained array methods (e.g. `.map().filter()`, `.flatMap()`, and repeated `.filter()` over the same large list like `profiles`) leads to redundant O(n) passes over data and allocates unnecessary intermediate arrays. This blocks the main thread longer than necessary when calculating basic statistics like `uniqueCities`, `uniqueTechs`, or total counts.
 **Action:** Consolidate statistical aggregations over large object arrays into a single O(n) `for` loop that updates multiple accumulators (like `Set` objects and primitive counters) in one pass, thereby improving performance and reducing memory overhead.
+## 2024-07-20 - Memoization of filtering logic
+**Learning:** In pages with heavily interactive inputs (like `AdminPage` with a search bar), performing O(N) array filtering synchronously within the component body causes the expensive calculation to block every re-render, compounding latency on keystrokes.
+**Action:** Wrap any O(N) filtering operations (e.g. `profiles.filter(...)`) in `React.useMemo` to ensure they only re-run when their specific dependencies (`profiles` or `searchQuery`) actually change, completely skipping the overhead on unrelated state updates.

src/pages/admin-page.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useState } from "react";
+import { useEffect, useState, useMemo } from "react";
 import { useNavigate, Link } from "react-router-dom";
 import { Shield, Send, UserPlus, UserMinus, Users, Building2, Handshake, Download, Search, TrendingUp, ArrowUpRight, TriangleAlert, Clock, GitCommitHorizontal, UserRoundPlus, Layers as Layers3, Flag, UserCheck, MapPin, Trash2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
@@ -171,11 +171,11 @@ export function AdminPage() {
     );
   }
 
-  const filteredProfiles = profiles.filter((p) => {
+  const filteredProfiles = useMemo(() => profiles.filter((p) => {
     if (!searchQuery) return true;
     const q = searchQuery.toLowerCase();
     return p.full_name.toLowerCase().includes(q) || p.username.toLowerCase().includes(q) || p.city?.toLowerCase().includes(q);
-  });
+  }), [profiles, searchQuery]);
 
   // ⚡ Bolt: Consolidate data aggregation into a single O(n) pass
   // Avoids multiple redundant iterations and intermediate array allocations