list of gene variants is empty

list of variants retrieved by this js plugin is always empty:

var ELEMENT_ID = 18215;

minervaDefine({
  register: function (object) {
    console.log("registering test plugin");
    $(object.element).append("<button id='get-selected'>selected overlays</button>");
    $("#get-selected").on("click",function(){
      object.project.map.getVisibleDataOverlays().then(function(overlays){
        console.log("selected overlays", overlays);
        var promises = []
        for (var i=0;i<overlays.length;i++) {
          var overlay = overlays[i];
          if (overlay.getType() == "GENETIC_VARIANT") {
            promises.push(overlay.getFullAliasesById(ELEMENT_ID));
          } else {
            console.log("Overlay "+overlay.getName()+" does not contain gene variants");
          }
        }
        return Promise.all(promises);
      }).then(function(selectedOverlayElementData){
        for (var i=0;i<selectedOverlayElementData.length;i++) {
          var overlayData = selectedOverlayElementData[i];
          if (overlayData!==undefined && overlayData!==null) {
            for (var j=0;j<overlayData.length;j++) {
              console.log(overlayData[j]);
              console.log(overlayData[j].getGeneVariants);
              console.log("Gene variants",overlayData[j].getGeneVariants());
            }
          } else {
            console.log("Element is not present in overlay");
          }
        }
      });
    });
  },
  unregister: function () {
    console.log("unregistering test plugin");
  },
  getName: function () {
    return "test plugin";
  },
  getVersion: function () {
    return "0.0.1";
  }
});