function Dijkstra(toX, toY, passableCallback, options) {
      var _this20;
      _this20 = _Path.call(this, toX, toY, passableCallback, options) || this;
      _this20._computed = {};
      _this20._todo = [];
      _this20._add(toX, toY, null);
      return _this20;
    }
@class Simplified Dijkstra's algorithm: all edges have a value of 1
@augments ROT.Path
@see ROT.Path