How to calculate the distance of a polyline in Leaflet like geojson.io?

Question

I am working on a map with Mapbox and Leaflet and I am supposed to let the user draw polygons and calculate and show the are of that polygon and I also need to let the user draw

Answer 1

I solved this by extending L.Polyline class, and using LatLng's distanceTo method:

L.Polyline = L.Polyline.include({
    getDistance: function(system) {
        // distance in meters
        var mDistanse = 0,
            length = this._latlngs.length;
        for (var i = 1; i < length; i++) {
            mDistanse += this._latlngs[i].distanceTo(this._latlngs[i - 1]);
        }
        // optional
        if (system === 'imperial') {
            return mDistanse / 1609.34;
        } else {
            return mDistanse / 1000;
        }
    }
});

Hope it helps someone.