diff --git a/types/leaflet/index.d.ts b/types/leaflet/index.d.ts
index 71c6ea4adf..310977d9f4 100644
--- a/types/leaflet/index.d.ts
+++ b/types/leaflet/index.d.ts
@@ -18,18 +18,15 @@ export class Class {
 
 export class Transformation {
     constructor(a: number, b: number, c: number, d: number);
-
     transform(point: Point, scale?: number): Point;
-
     untransform(point: Point, scale?: number): Point;
 }
 
 export namespace LineUtil {
     function simplify(points: Point[], tolerance: number): Point[];
-
     function pointToSegmentDistance(p: Point, p1: Point, p2: Point): number;
-
     function closestPointOnSegment(p: Point, p1: Point, p2: Point): Point;
+    function isFlat(latlngs: LatLngExpression[]): boolean;
 }
 
 export namespace PolyUtil {
diff --git a/types/proj4leaflet/index.d.ts b/types/proj4leaflet/index.d.ts
index 81a16100e4..a33a3efb32 100644
--- a/types/proj4leaflet/index.d.ts
+++ b/types/proj4leaflet/index.d.ts
@@ -42,7 +42,7 @@ declare module 'leaflet' {
 
     class GeoJSON extends L.GeoJSON {}
 
-    const geoJson: (geojson?: geojson.GeoJsonObject, options?: GeoJSONOptions) => GeoJSON;
+    const geoJson: (geojson?: Proj4GeoJSONFeature, options?: GeoJSONOptions) => GeoJSON;
 
     class ImageOverlay extends L.ImageOverlay {}
 
@@ -57,3 +57,6 @@ declare module 'leaflet' {
     }
   }
 }
+export type Proj4GeoJSONFeature = geojson.Feature<geojson.GeometryObject> & {
+  crs?: { type: string; properties: { name: string } }
+};
diff --git a/types/proj4leaflet/proj4leaflet-tests.ts b/types/proj4leaflet/proj4leaflet-tests.ts
index e061a4ca3a..930473d793 100644
--- a/types/proj4leaflet/proj4leaflet-tests.ts
+++ b/types/proj4leaflet/proj4leaflet-tests.ts
@@ -1,6 +1,5 @@
 import * as L from 'leaflet';
-import 'proj4leaflet';
-
+import * as proj4leaflet from "proj4leaflet";
 import * as proj4 from 'proj4';
 
 import LatLngBoundsExpression = L.LatLngBoundsExpression;
@@ -43,12 +42,13 @@ const crs3 = new L.Proj.CRS('EPSG:3006',
 // geoJson
 proj4.defs("urn:ogc:def:crs:EPSG::26915", "+proj=utm +zone=15 +ellps=GRS80 +datum=NAD83 +units=m +no_defs");
 
-const geojson = {
+const geojson: proj4leaflet.Proj4GeoJSONFeature = {
   type: "Feature",
   geometry: {
     type: "Point",
     coordinates: [481650, 4980105]
   },
+  properties: {},
   crs: {
     type: "name",
     properties: {