无法在角度2中读取未定义的属性“getPosition”

Question

当我提交按钮时，显示错误。错误是“无法读取未定义的属性'getPosition'”。如果有人能帮助我，我将非常感激。 这是我的代码

 this.map.on(GoogleMapsEvent.MY_LOCATION_BUTTON_CLICK).subscribe((map: GoogleMap) => {

    if (this.isViewLoaded) {

      this.map.getCameraPosition().then((camera: CameraPosition) => {

        let target: LatLng = <LatLng> camera.target;
        this.marker.setPosition(target);
      });
    }
  });


this.marker.getPosition().then(position => {

  this.place.location = position;

  this.place.save().then(place => {
    this.showContentView();
    this.translate.get('PLACE_ADDED').subscribe(str => this.showToast(str));
  }, error => {
    this.showContentView();
    this.translate.get('ERROR_PLACE_ADD').subscribe(str => this.showToast(str));
  });
});