geojson-area
Calculate the area inside of any GeoJSON geometry.
usage
npm install @mapbox/geojson-area
example
var geojsonArea = require('@mapbox/geojson-area');
var area = geojsonArea.geometry(obj);api
geojsonArea.geometry(obj)
Given a Geometry object, return contained
area as square meters. Invalid input will return null.
Adapted from OpenLayers