Making a GeoJSON layer editable with the Leaflet.Editable plugin

For future searchers, an alternative solution is to catch the 'edited' event from the editable extension and update the GeoJSON geometry to match that of the layer:

 this.mapHost.map.on('editable:vertex:dragend', (event: any) =>
      {
         // Note: the layer latlngs have been updated here but not the geojson geometry
         // copy changes to geojson
         event.layer.feature.geometry = (event.layer as any).toGeoJSON().geometry;
      });