toggle() {
    if (!this.popup.visible) {
      this.open();
    } else {
      this.close();
    }
  }
/**
   * Toggle the dropdown list open/closed state
   * @private
   */
Toggle the dropdown list open/closed state
@private
Toggle the dropdown list open / closed state @private
toggle() {
    if (!this.popup.visible) {
      this.open();
    } else {
      this.close();
    }
  }
toggle ( ) { if ( ! this . popup . visible ) { this . open ( ) ; } else { this . close ( ) ; } }
Toggle the dropdown list open/closed state
 @private
Toggle the dropdown list open / closed state @private