title: How to get the area string from a polygon using leaflet.draw
body: <p>I am trying to get the area measurements of polygons so I can list them in a table to the side of the map, next to the name of the polygon.  This is what I have tried with no success:</p>
  
  <pre><code>$("#polygon").on("click", function (){
      createPolygon = new L.Draw.Polygon(map, drawControl.options.polygon);
      createPolygon.enable();
  }
  
  var polygon = new L.featureGroup();
  
  map.on('draw:created', function (e) {
      var type = e.layerType,
          layer = e.layer;
      if (type === 'polygon') {
        polygons.addLayer(layer);
      }
      var seeArea = createPolygon._getMeasurementString();
     console.log(seeArea);  //Returns null
  }
  </code></pre>
  
  <p>Any help on this would be appreciated!  </p>