Reversed the order in which random polygon points are generated to sa…

…tisfy the right hand rule (#2715)

Reversed the order in which random polygon points are generated to satisfy to the right hand rule for polygons. Added a simple benchmark test for turf-random.

packages/turf-random/bench.ts

@@ -1,15 +1,16 @@
-// I don't think this bench test does anything? There is no entry point into
-// the module called random() that takes a string?
+import Benchmark, { Event } from "benchmark";
+import { randomPolygon } from "./index.js";
 
-import { random } from "./index.js";
-import Benchmark from "benchmark";
+let totalTime = 0.0;
+const suite = new Benchmark.Suite("turf-random");
 
-var suite = new Benchmark.Suite("turf-random");
 suite
-  .add("turf-random", function () {
-    random("point");
-  })
-  .on("cycle", function (event) {
-    console.log(String(event.target));
+  .add("turf-random", () => randomPolygon(1, { num_vertices: 100000 }), {
+    onComplete: (e: Event) =>
+      (totalTime = totalTime += e.target.times?.elapsed),
   })
+  .on("cycle", (e: Event) => console.log(String(e.target)))
+  .on("complete", () =>
+    console.log(`completed in ${totalTime.toFixed(2)} seconds`)
+  )
   .run();

packages/turf-random/index.ts

@@ -145,16 +145,16 @@ function randomPolygon(
 
   const features = [];
   for (let i = 0; i < count; i++) {
-    let vertices: any[] = [];
+    let vertices: number[][] = [];
     const circleOffsets = [...Array(options.num_vertices + 1)].map(Math.random);
 
     // Sum Offsets
-    circleOffsets.forEach((cur: any, index: number, arr: any[]) => {
+    circleOffsets.forEach((cur, index, arr) => {
       arr[index] = index > 0 ? cur + arr[index - 1] : cur;
     });
 
     // scaleOffsets
-    circleOffsets.forEach((cur: any) => {
+    circleOffsets.forEach((cur) => {
       cur = (cur * 2 * Math.PI) / circleOffsets[circleOffsets.length - 1];
       const radialScaler = Math.random();
       vertices.push([
@@ -165,9 +165,9 @@ function randomPolygon(
     vertices[vertices.length - 1] = vertices[0]; // close the ring
 
     // center the polygon around something
-    vertices = vertices.map(
-      vertexToCoordinate(randomPositionUnchecked(paddedBbox))
-    );
+    vertices = vertices
+      .reverse() // Make counter-clockwise to adhere to right hand rule.
+      .map(vertexToCoordinate(randomPositionUnchecked(paddedBbox)));
     features.push(polygon([vertices]));
   }
   return featureCollection(features);