[LayaAir 2.0]TieldMap is not counstructer

代码如下：
//创建TiledMap实例
        this._tMap = new TiledMap();
        //创建Rectangle实例，视口区域
        var viewRect:Laya.Rectangle = new Laya.Rectangle();
        console.log(this._tMap);
        //创建TiledMap地图
        this._tMap.createMap("../bin/map/orthogonal-outside.json",viewRect,Laya.Handler.create(this,this.onComplete));