perf(monitor): bound map refresh fingerprints

vehicle-data-platform/apps/web/src/v2/map/FleetMap.test.tsx

@@ -2,7 +2,7 @@ import { act, cleanup, fireEvent, render, screen, waitFor } from '@testing-libra
 import { afterEach, expect, test, vi } from 'vitest';
 import type { MonitorMapResponse } from '../../api/types';
 import { wgs84ToGcj02, type AMapLike, type AMapMap, type AMapMassPoint } from '../../integrations/amap';
-import { FleetMap } from './FleetMap';
+import { FleetMap, massPointFingerprint } from './FleetMap';
 
 const setData = vi.fn<(data: AMapMassPoint[]) => void>();
 const setStyle = vi.fn();
@@ -124,6 +124,23 @@ const pointMap: MonitorMapResponse = {
   }]
 };
 
+test('keeps large fleet redraw fingerprints constant-size and sensitive to point changes', () => {
+  const manyPoints = Array.from({ length: 10_000 }, (_, index) => ({
+    ...pointMap.points[index % pointMap.points.length],
+    vin: `LARGE-FLEET-${index}`,
+    longitude: 113.26 + index / 1_000_000
+  }));
+  const fingerprint = massPointFingerprint('points', [], manyPoints, []);
+  const changed = massPointFingerprint('points', [], [
+    ...manyPoints.slice(0, -1),
+    { ...manyPoints[manyPoints.length - 1], longitude: 114.5 }
+  ], []);
+
+  expect(fingerprint.length).toBeLessThan(40);
+  expect(changed).not.toBe(fingerprint);
+  expect(massPointFingerprint('points', [], manyPoints, [])).toBe(fingerprint);
+});
+
 function amapMock(): AMapLike {
   return {
     Map: TestMap as unknown as AMapLike['Map'],