Javascript Firebase:尝试删除文档并返回上一屏幕时出现问题

我正在想办法解决这个问题

查看文档时，我想删除它，然后使用

StackActions.pop（1）

返回上一屏幕

我的州是这样建立的：

  const [loading, setLoading] = useState(true);
  const [sensorData, setSensorData] = useState();

  const currentFarmId = useSelector((state) => state.session.currentFarm.farmId);
  const currentSensorId = useSelector((state) => state.session.currentSensor.sensorId);

  useEffect(() => {

    return db
      .collection('farms')
      .doc(currentFarmId)
      .collection('sensors')
      .doc(currentSensorId)
      .onSnapshot((documentSnapshot) => {
        const data = documentSnapshot.data();
        setSensorData(data);
        setLoading(false);
      });

  }, [currentFarmId, currentSensorId]);s

  if (loading) {
    return <LoadingIndicator />;
  }

  // Render
  return (
    <View>
      <Text>{sensorData.sensorType}</Text>
    </View>

我将数据加载到传感器数据中，如下所示：

  const [loading, setLoading] = useState(true);
  const [sensorData, setSensorData] = useState();

  const currentFarmId = useSelector((state) => state.session.currentFarm.farmId);
  const currentSensorId = useSelector((state) => state.session.currentSensor.sensorId);

  useEffect(() => {

    return db
      .collection('farms')
      .doc(currentFarmId)
      .collection('sensors')
      .doc(currentSensorId)
      .onSnapshot((documentSnapshot) => {
        const data = documentSnapshot.data();
        setSensorData(data);
        setLoading(false);
      });

  }, [currentFarmId, currentSensorId]);s

  if (loading) {
    return <LoadingIndicator />;
  }

  // Render
  return (
    <View>
      <Text>{sensorData.sensorType}</Text>
    </View>

这是我的删除代码：

  function onDeleteSensorHandler() {
    deleteSensor()
      .then(() => {
        const afterDeleteNavigateAction = StackActions.pop(1);
        props.navigation.dispatch(afterDeleteNavigateAction);
      });
  }

  async function deleteSensor() {

    setLoading(true);

    await db
      .collection('farms')
      .doc(currentFarmId)
      .collection('sensors')
      .doc(currentSensorId)
      .delete();

    setLoading(false);

  }

我把屏幕渲染成这样：

  const [loading, setLoading] = useState(true);
  const [sensorData, setSensorData] = useState();

  const currentFarmId = useSelector((state) => state.session.currentFarm.farmId);
  const currentSensorId = useSelector((state) => state.session.currentSensor.sensorId);

  useEffect(() => {

    return db
      .collection('farms')
      .doc(currentFarmId)
      .collection('sensors')
      .doc(currentSensorId)
      .onSnapshot((documentSnapshot) => {
        const data = documentSnapshot.data();
        setSensorData(data);
        setLoading(false);
      });

  }, [currentFarmId, currentSensorId]);s

  if (loading) {
    return <LoadingIndicator />;
  }

  // Render
  return (
    <View>
      <Text>{sensorData.sensorType}</Text>
    </View>

if（加载）{
返回；
}
//渲染
返回(
{sensorData.sensorType}

我的代码正确地删除了文档。但是，问题是我得到了一个错误：

[未处理的承诺拒绝：类型错误：未定义不是对象（评估'sensorData.sensorType'）]

---

这似乎表明React试图在传感器被删除后重新渲染屏幕或其他什么？我的代码中有缺陷吗？

应该很简单，

sensorData

为空或未定义，这就是为什么会出现异常

简单地编辑上面的代码到下面应该可以解决这个问题

<Text>{sensorData?.sensorType}</Text>