Fix convex function ignoring given properties

packages/turf-convex/index.ts

@@ -56,7 +56,7 @@ function convex<P extends GeoJsonProperties = GeoJsonProperties>(
 
   // Convex hull should have at least 3 different vertices in order to create a valid polygon
   if (convexHull.length > 3) {
-    return polygon([convexHull]);
+    return polygon<P>([convexHull], options.properties);
   }
   return null;
 }

packages/turf-convex/test.ts

@@ -6,6 +6,7 @@ import { writeJsonFileSync } from "write-json-file";
 import { loadJsonFileSync } from "load-json-file";
 import { featureCollection } from "@turf/helpers";
 import { convex } from "./index.js";
+import { FeatureCollection } from "geojson";
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
@@ -32,3 +33,17 @@ test("turf-convex -- empty", (t) => {
   t.deepEqual(convex(featureCollection([])), null, "corner case: null hull");
   t.end();
 });
+
+test("turf-convex -- properties are returned", (t) => {
+  const geoJson = loadJsonFileSync<FeatureCollection>(
+    "./test/in/elevation2.geojson"
+  );
+  const expectedProperties = { cadastralData: [1220, 1290, 1440, 1943] };
+  const actualPolygon = convex(geoJson, { properties: expectedProperties });
+  t.deepEqual(
+    actualPolygon?.properties,
+    expectedProperties,
+    "properties do not match"
+  );
+  t.end();
+});