# keyByPolygonId function

Map <String, Polygon> keyByPolygonId (

1. Iterable <Polygon> polylines

)

## Implementation

    Map<String, Polygon> keyByPolygonId(Iterable<Polygon> polylines) {
      if (polylines == null) {
        return <String, Polygon>{};
      }
      return Map<String, Polygon>.fromEntries(polylines.map((Polygon polyline) =>
          MapEntry<String, Polygon>(polyline.id, polyline.clone())));
    }