routing

website/src/lib/closest-point.test.ts

@@ -1,6 +1,6 @@
 import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
-import { closestPointIndex } from './closest-point';
+import { closestPointIndex, closestPointIndexIn } from './closest-point';
 
 describe('closestPointIndex', () => {
     const line = [0, 0, 1, 0, 2, 0, 2, 1];
@@ -27,3 +27,24 @@ describe('closestPointIndex', () => {
         assert.equal(closestPointIndex(coordinates, { lng: 3, lat: 0.01 }), 0);
     });
 });
+
+describe('closestPointIndexIn', () => {
+    const lng = [0, 1, 2, 2, 5, 6];
+    const lat = [0, 0, 0, 1, 5, 5];
+
+    it('gives the index in the arrays, looking at the given range only', () => {
+        assert.equal(closestPointIndexIn(lng, lat, 0, 4, { lng: 0.8, lat: 0.1 }), 1);
+        // the range starts after the closest points
+        assert.equal(closestPointIndexIn(lng, lat, 4, 6, { lng: 0.8, lat: 0.1 }), 4);
+        assert.equal(closestPointIndexIn(lng, lat, 4, 6, { lng: 5.9, lat: 5.1 }), 5);
+    });
+
+    it('has no point in an empty range', () => {
+        assert.equal(closestPointIndexIn(lng, lat, 3, 3, { lng: 0, lat: 0 }), undefined);
+        assert.equal(closestPointIndexIn(lng, lat, 4, 2, { lng: 0, lat: 0 }), undefined);
+    });
+
+    it('is the point itself for a range of one point', () => {
+        assert.equal(closestPointIndexIn(lng, lat, 3, 4, { lng: 9, lat: 9 }), 3);
+    });
+});