function getGeom(geojson) {
    if (geojson.type === "Feature") {
        return geojson.geometry;
    }
    return geojson;
}
Get Geometry from Feature or Geometry Object

@param {Feature|Geometry} geojson GeoJSON Feature or Geometry Object
@returns {Geometry|null} GeoJSON Geometry Object
@throws {Error} if geojson is not a Feature or Geometry Object
@example
var point = {
  "type": "Feature",
  "properties": {},
  "geometry": {
    "type": "Point",
    "coordinates": [110, 40]
  }
}
var geom = turf.getGeom(point)
//={"type": "Point", "coordinates": [110, 40]}