turf-nearest-point-on-line: fix for points far away from the segment endpoints

packages/turf-nearest-point-on-line/index.ts

@@ -250,13 +250,10 @@ function nearestPointOnSegment(
   // If angle AI or BI is greater than angleAB, I lies on the circle *beyond* A
   // and B so use the closest of A or B as the intersection
   if (angle(A, I) > angleAB || angle(B, I) > angleAB) {
-    if (
-      distance(vectorToLngLat(I), vectorToLngLat(A)) <=
-      distance(vectorToLngLat(I), vectorToLngLat(B))
-    ) {
-      return [vectorToLngLat(A), true, false];
+    if (distance(posC, posA) <= distance(posC, posB)) {
+      return [posA, true, false];
     } else {
-      return [vectorToLngLat(B), false, true];
+      return [posB, false, true];
     }
   }
 

packages/turf-nearest-point-on-line/package.json

@@ -3,6 +3,9 @@
   "version": "7.2.0",
   "description": "Finds the nearest point on a line to a given point",
   "author": "Turf Authors",
+  "contributors": [
+    "mike castleman <@mlc>"
+  ],
   "license": "MIT",
   "bugs": {
     "url": "https://github.com/Turfjs/turf/issues"

packages/turf-nearest-point-on-line/test.ts

@@ -517,3 +517,20 @@ test("turf-nearest-point-on-line -- issue 2808 redundant point support", (t) =>
 
   t.end();
 });
+
+test("turf-nearest-point-on-line -- issue 2870 faraway point", (t) => {
+  const line1 = lineString([
+    [-96.80974, -58.32062],
+    [-50.2464, 38.36643],
+  ]);
+  const thePoint = point([13.6023, 46.50646]);
+
+  const nearest = nearestPointOnLine(line1, thePoint);
+  t.deepEqual(
+    truncate(nearest, { precision: 8 }).geometry.coordinates,
+    [-50.2464, 38.36643],
+    "nearest point should be [-50.2464, 38.36643]"
+  );
+
+  t.end();
+});