code: function (r, n) {
      const frame = r.rect(n.point[0] - 30, n.point[1] - 13, 60, 44);
      frame.attr({
        fill: '#feb',
        r: 12,
        'stroke-width': (n.distance === 0 ? '3px' : '1px'),
      });
  
      /* the Raphael set is obligatory, containing all you want to display */
      const set = r.set().push(frame,
          /* custom objects go here */
          r.text(n.point[0], n.point[1] + 10, `${n.label || n.id}\n(${n.distance === undefined ? 'Infinity' : n.distance})`));
      return set;
    }
docs: /* Showcase of the Bellman-Ford search algorithm finding shortest paths
  from one point to every node /* We need to write a new node renderer function to display the computed
  distance.
  (the Raphael graph drawing implementation of Dracula can draw this shape,
  please consult the RaphaelJS reference for details http://raphaeljs.com/)