toJSON(obj) {
        var json = BaseSerializer.prototype.toJSON.call(this, obj);

        json.autoUpdate = obj.autoUpdate;
        json.enabled = obj.enabled;
        json.needsUpdate = obj.needsUpdate;
        json.type = obj.type;

        return json;
    }
WebGLShadowMapSerializer
@author tengge / https://github.com/tengge1