wip, type problem

lib/src/geojson.dart

@@ -587,7 +587,7 @@ class GeometryCollection extends GeometryObject {
       );
 }
 
-/// Feature, as specified here https://tools.ietf.org/html/rfc7946#section-3.2
+/// Feature, as specified here https://tools.ietf.o rg/html/rfc7946#section-3.2
 class Feature<T extends GeometryObject> extends GeoJSONObject {
   dynamic id;
   Map<String, dynamic>? properties;

lib/src/invariant.dart

@@ -1,3 +1,5 @@
+import 'dart:developer';
+
 import 'package:turf/turf.dart';
 
 ///
@@ -43,24 +45,31 @@ Position getCoord(dynamic coord) {
 /// var coords = turf.getCoords(poly);
 /// //= [[[119.32, -8.7], [119.55, -8.69], [119.51, -8.54], [119.32, -8.7]]]
 ///
-List getCoords(dynamic coords) {
+List<dynamic> getCoords(dynamic coords) {
   if (coords == null) {
     throw Exception("coords is required");
   }
 
+  if (coords is List) {
+    return coords;
+  }
+
   if (coords is Feature && coords.geometry != null) {
     _getCoordsForGeometry(coords.geometry!);
   }
 
-  if (coords is List) {
-    return coords;
+  if (coords is GeometryType) {
+    _getCoordsForGeometry(coords.coordinates);
   }
-  return _getCoordsForGeometry(coords);
+
+    throw Exception(
+        "{Array<any>|Geometry|Feature} coords Feature, Geometry Object or an Array");
 }
 
 _getCoordsForGeometry(GeometryObject geom) {
   if (geom is Point || geom is GeometryCollection) {
     throw Exception("Type must contain a list of Positions e.g Polygon");
   }
+
   return (geom as GeometryType).coordinates;
 }

test/components/invariant_test.dart

@@ -1,6 +1,9 @@
+import 'dart:math';
+
 import 'package:test/test.dart';
 import 'package:turf/helpers.dart';
 import 'package:turf/src/invariant.dart';
+// import 'package:collection/collection.dart';
 
 main() {
   LineString line1 = LineString(coordinates: [Position(1, 2), Position(3, 4)]);
@@ -18,12 +21,23 @@ main() {
   test("invariant -- getCoords", () {
     var feature2 = Feature<LineString>(geometry: line1);
     expect(() => getCoords(null), throwsA(isA<Exception>()));
-    expect(() => getCoords(feature1), throwsA(isA<Exception>())); 
+    expect(
+        getCoords([
+          [119.32, -8.7],
+          [119.55, -8.69],
+          [119.51, -8.54],
+          [119.32, -8.7]
+        ]),
+        equals([
+          [119.32, -8.7],
+          [119.55, -8.69],
+          [119.51, -8.54],
+          [119.32, -8.7]
+        ]));
+    expect(() => getCoords(feature1), throwsA(isA<Exception>()));
+    expect(() => getCoords(feature1), throwsA(isA<Exception>()));
     var coords = getCoords(feature2);
-    expect(coords.length, feature2.geometry!.coordinates.length);
-    expect(coords.first, feature2.geometry!.coordinates.first);
-    expect(coords.last, feature2.geometry!.coordinates.last);
-
+    expect(coords, equals([Position(1, 2), Position(3, 4)]));
   });
 /*