Ok, then you have to use that typedef in parser's `write` signature. Something like

    /**
     * @param {nativeElements: Array.<ol.parser.WFSNative>} options Write options
     *
    ol.parser.ogc.WFS_v1.prototype.write = function(features, options) {}

You'll have to list all other possible options as well. And if people need to be able to call this from an application, you'll also need to export the typedef for options.