Close volumes

  var closeVolume = function(pathVolume) {
    var firstPoint, lastPoint, points;

    if (pathVolume === null) {
      return null;
    }

    points = pathVolume.shape.points;

    if (points.length < 2) {
      return pathVolume;
    }

    firstPoint = points[0];
    lastPoint = points[points.length - 1];

    if (firstPoint.x !== lastPoint.x || firstPoint.y !== lastPoint.y || firstPoint.lh !== lastPoint.lh || firstPoint.rh !== lastPoint.rh) {
      points.push(firstPoint);
    }

    return pathVolume;
  };