return.js

return {
    type: "Topology",
    bbox: [x0, y0, x1, y1],
    transform: {
      scale: [1 / kx, 1 / ky],
      translate: [x0, y0]
    },
    objects: objects,
    arcs: arcs.map(function(arc) {
      var i = 0,
          n = arc.length,
          point = arc[0],
          x1 = point[0], x2, dx,
          y1 = point[1], y2, dy,
          points = [[x1, y1]];
      while (++i < n) {
        point = arc[i];
        x2 = point[0];
        y2 = point[1];
        dx = x2 - x1;
        dy = y2 - y1;
        if (dx || dy) {
          points.push([dx, dy]);
          x1 = x2, y1 = y2;
        }
      }
      return points;
    })
  };
};