diff --git a/src/ol/format/geojsonformat.js b/src/ol/format/geojsonformat.js
index 457953a03d..cdfc8a01b3 100644
--- a/src/ol/format/geojsonformat.js
+++ b/src/ol/format/geojsonformat.js
@@ -482,7 +482,7 @@ ol.format.GeoJSON.prototype.readProjectionFromObject = function(object) {
  *
  * @function
  * @param {ol.Feature} feature Feature.
- * @param {olx.format.WriteOptions} options Write options.
+ * @param {olx.format.WriteOptions=} opt_options Write options.
  * @return {string} GeoJSON.
  * @api stable
  */