Need to understand if there is a marker on the 2gis map?

Question

2GIS

When clicked, this method is executed:

close(){
      this.$emit('close-popup', this.isOpenRc)
      document.querySelector('.popup-rc-content').scrollTop=0;
      if(window.innerWidth<500){
        this.marker.remove();         // это удаляет маркер с карты
      }

If there is no marker on the map, then it gives an error - it is necessary that it does not perform this action if there is no marker on the map. How can you do?