lgtm

frontend/src/lib/map-utils.test.ts

@@ -21,9 +21,39 @@ import {
   getFeatureFillColor,
   getMapCenterForTargetScreenPoint,
   getPoiIconUrl,
+  selectSpacedItems,
   zoomToResolution,
 } from './map-utils';
 
+describe('selectSpacedItems', () => {
+  const mk = (id: string, x: number, y: number) => ({ item: id, x, y });
+
+  it('keeps every item when none overlap', () => {
+    const items = [mk('a', 0, 0), mk('b', 200, 0), mk('c', 0, 200)];
+    const kept = selectSpacedItems(items, 130, 34, 40);
+    expect(kept.map((k) => k.item)).toEqual(['a', 'b', 'c']);
+  });
+
+  it('culls items that fall within the spacing of an already-kept item', () => {
+    // b and c sit on top of a; d is clear.
+    const items = [mk('a', 100, 100), mk('b', 120, 110), mk('c', 150, 100), mk('d', 400, 400)];
+    const kept = selectSpacedItems(items, 130, 34, 40);
+    expect(kept.map((k) => k.item)).toEqual(['a', 'd']);
+  });
+
+  it('treats dx and dy independently (far enough on either axis is kept)', () => {
+    const items = [mk('a', 0, 0), mk('b', 10, 40)]; // dx<130 but dy>=34
+    const kept = selectSpacedItems(items, 130, 34, 40);
+    expect(kept.map((k) => k.item)).toEqual(['a', 'b']);
+  });
+
+  it('stops at the max cap', () => {
+    const items = Array.from({ length: 100 }, (_, i) => mk(String(i), i * 500, 0));
+    const kept = selectSpacedItems(items, 130, 34, 40);
+    expect(kept).toHaveLength(40);
+  });
+});
+
 describe('map utilities', () => {
   it('maps zoom levels to H3 resolutions at configured thresholds', () => {
     expect(zoomToResolution(6.9)).toBe(5);