Carte Editor sends FeatureCollection to the server

app/javascript/shared/carte-editor.js

@@ -1,9 +1,10 @@
 import L from 'leaflet';
 import FreeDraw from 'leaflet-freedraw';
+import area from '@turf/area';
 import { fire, delegate } from '@utils';
 import $ from 'jquery';
 
-import polygonArea from './polygon_area';
+import createFeatureCollection from './create-feature-collection';
 
 const MAPS = new WeakMap();
 
@@ -81,13 +82,18 @@ function drawUserSelectionEditor(map, { selection }) {
 
 export function addFreeDrawEvents(map, selector) {
   const input = findInput(selector);
+
   map.freeDraw.on('markers', ({ latLngs }) => {
     if (latLngs.length === 0) {
       input.value = EMPTY_GEO_JSON;
-    } else if (polygonArea(latLngs) < 300000) {
-      input.value = JSON.stringify(latLngs);
     } else {
-      input.value = ERROR_GEO_JSON;
+      const featureCollection = createFeatureCollection(latLngs);
+
+      if (area(featureCollection) < 300000) {
+        input.value = JSON.stringify(featureCollection);
+      } else {
+        input.value = ERROR_GEO_JSON;
+      }
     }
 
     fire(input, 'change');
@@ -121,7 +127,7 @@ function getCurrentMap(element) {
   }
 }
 
-const EMPTY_GEO_JSON = '[]';
+const EMPTY_GEO_JSON = '{ "type": "FeatureCollection", "features": [] }';
 const ERROR_GEO_JSON = '';
 
 function findInput(selector) {

app/javascript/shared/create-feature-collection.js

@@ -1,16 +1,16 @@
-import area from '@turf/area';
-
-export default function polygonArea(latLngs) {
-  return area({
+export default function createFeatureCollection(latLngs) {
+  return {
     type: 'FeatureCollection',
     features: latLngs.map(featurePolygonLatLngs)
-  });
+  };
 }
 
 function featurePolygonLatLngs(latLngs) {
   return {
     type: 'Feature',
-    properties: {},
+    properties: {
+      source: 'selection_utilisateur'
+    },
     geometry: {
       type: 'Polygon',
       coordinates: [latLngs.map(({ lng, lat }) => [lng, lat])]