perfect-postcode/frontend/src/lib/h3-selection.test.ts
2026-05-06 22:40:46 +01:00

46 lines
1.6 KiB
TypeScript

import { cellToChildren, cellToLatLng, latLngToCell } from 'h3-js';
import { describe, expect, it } from 'vitest';
import type { HexagonData } from '../types';
import { findOverlappingMatchingHexagon, hasMatchingHexagonAtResolution } from './h3-selection';
function hexagonData(h3: string, count: number): HexagonData {
const [lat, lon] = cellToLatLng(h3);
return { h3, count, lat, lon };
}
describe('h3 selection helpers', () => {
it('finds a matching higher-resolution hexagon that overlaps the previous hexagon', () => {
const parent = latLngToCell(51.5, -0.1, 8);
const children = cellToChildren(parent, 9);
const selected = findOverlappingMatchingHexagon(
parent,
[hexagonData(children[0], 0), hexagonData(children[1], 4)],
9
);
expect(selected?.h3).toBe(children[1]);
});
it('rejects candidates that do not overlap or have no matches', () => {
const parent = latLngToCell(51.5, -0.1, 8);
const nearbyChild = cellToChildren(parent, 9)[0];
const distant = latLngToCell(52.2, -0.1, 9);
expect(
findOverlappingMatchingHexagon(
parent,
[hexagonData(nearbyChild, 0), hexagonData(distant, 12)],
9
)
).toBeNull();
});
it('detects when target-resolution matching data is loaded', () => {
const parent = latLngToCell(51.5, -0.1, 8);
const child = cellToChildren(parent, 9)[0];
expect(hasMatchingHexagonAtResolution([hexagonData(child, 1)], 9)).toBe(true);
expect(hasMatchingHexagonAtResolution([hexagonData(child, 0)], 9)).toBe(false);
expect(hasMatchingHexagonAtResolution([hexagonData(parent, 1)], 9)).toBe(false);
});
});