doc: fix modify polygon demo

Author: jeremy-eychenne

src/app/modify-polygon/modify-polygon.component.ts

@@ -3,6 +3,8 @@ import { Feature } from 'ol';
 import { GeoJSON } from 'ol/format';
 import { Polygon } from 'ol/geom';
 import Projection from 'ol/proj/Projection';
+import { FeatureLike } from 'ol/Feature';
+import { Feature as GeoJSonFeature, Polygon as GeoJSonPolygon } from 'geojson';
 
 @Component({
   selector: 'app-modify-polygon',
@@ -27,7 +29,7 @@ import Projection from 'ol/proj/Projection';
         <aol-source-vector>
           <aol-feature>
             <aol-geometry-polygon>
-              <aol-collection-coordinates [coordinates]="feature.getGeometry().getCoordinates()" [srid]="'EPSG:4326'">
+              <aol-collection-coordinates [coordinates]="feature.geometry.coordinates" [srid]="'EPSG:4326'">
               </aol-collection-coordinates>
             </aol-geometry-polygon>
           </aol-feature>
@@ -65,22 +67,27 @@ export class ModifyPolygonComponent {
   displayProj = new Projection({ code: 'EPSG:3857' });
   inputProj = new Projection({ code: 'EPSG:4326' });
 
-  feature = new Feature<Polygon>({
-    geometry: new Polygon([
-      [
-        [-1.7138671875, 43.35713822211053],
-        [4.515380859375, 43.35713822211053],
-        [4.515380859375, 47.76886840424207],
-        [-1.7138671875, 47.76886840424207],
-        [-1.7138671875, 43.35713822211053],
+  feature: GeoJSonFeature<GeoJSonPolygon> = {
+    geometry: {
+      coordinates: [
+        [
+          [-1.7138671875, 43.35713822211053],
+          [4.515380859375, 43.35713822211053],
+          [4.515380859375, 47.76886840424207],
+          [-1.7138671875, 47.76886840424207],
+          [-1.7138671875, 43.35713822211053],
+        ],
       ],
-    ]),
-  });
+      type: 'Polygon',
+    },
+    properties: {},
+    type: 'Feature',
+  };
 
-  modifyEnd(feature: Feature<Polygon>) {
-    this.feature = this.format.writeFeatureObject(feature, {
+  modifyEnd(feature: FeatureLike): void {
+    this.feature = this.format.writeFeatureObject(feature as Feature<Polygon>, {
       dataProjection: this.inputProj,
       featureProjection: this.displayProj,
-    }) as unknown as Feature<Polygon>;
+    }) as GeoJSonFeature<GeoJSonPolygon>;
   }
 }