From 25e71634e705db0d6363de4f81fc6d2b85c19a45 Mon Sep 17 00:00:00 2001
From: Paul Chavard <git@paul.chavard.net>
Date: Sat, 13 Oct 2018 10:55:40 +0200
Subject: [PATCH] carto: extract polygonArea helper

---
 .../old_design/carto/polygon_area.js          | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 app/javascript/old_design/carto/polygon_area.js

diff --git a/app/javascript/old_design/carto/polygon_area.js b/app/javascript/old_design/carto/polygon_area.js
new file mode 100644
index 000000000..d0384a310
--- /dev/null
+++ b/app/javascript/old_design/carto/polygon_area.js
@@ -0,0 +1,19 @@
+import area from '@turf/area';
+
+export default function polygonArea(latLngs) {
+  return area({
+    type: 'FeatureCollection',
+    features: latLngs.map(featurePolygonLatLngs)
+  });
+}
+
+function featurePolygonLatLngs(latLngs) {
+  return {
+    type: 'Feature',
+    properties: {},
+    geometry: {
+      type: 'Polygon',
+      coordinates: [latLngs.map(({ lng, lat }) => [lng, lat])]
+    }
+  };
+}