如何等待对最内部firebase函数的响应？_Firebase_React Native_Firebase Realtime Database_Google Cloud Functions

如何等待对最内部firebase函数的响应？

firebase react-native

如何等待对最内部firebase函数的响应？,firebase,react-native,firebase-realtime-database,google-cloud-functions,Firebase,React Native,Firebase Realtime Database,Google Cloud Functions,我正在使用Firebase函数读取Redux操作中的数据。问题是函数没有等待Firebase函数的响应。您可以在下面看到功能的所有代码。如何设置第二个firebase函数以等待响应 export const getSelectedGroupDetail = groupUid => dispatch => { dispatch({ type: GET_SELECTED_GROUP_DETAIL_START, }); firebase .database()

我正在使用Firebase函数读取Redux操作中的数据。问题是函数没有等待Firebase函数的响应。您可以在下面看到功能的所有代码。如何设置第二个firebase函数以等待响应

export const getSelectedGroupDetail = groupUid => dispatch => {
  dispatch({
    type: GET_SELECTED_GROUP_DETAIL_START,
  });
  firebase
    .database()
    .ref('/groups/' + groupUid)
    .once('value')
    .then(function (snapshot) {
      const membersList = _.map(snapshot.val().members, (val, uid) => ({ ...val, uid }));

      let groupMembersList = _.map(selectedGroupData.members, (val, uid) => {
    return { ...val, uid };
  });
      for (let index = 0; index < groupMembersList.length; index++) {
        firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
          .then(function (snapshot) {
            let name = snapshot.val().displayName;
            groupMembersList[index] = { ...groupMembersList[index], name };
          })
    .catch(e => console.log(e.message));
      }

      const yeniGrupDetayi = { ...snapshot.val(), uid: groupUid, membersList };
      console.log('ACTION NE YAZDI ? ===>', yeniGrupDetayi);
      dispatch({
        type: GET_SELECTED_GROUP_DETAIL_SUCCESS,
        payload: yeniGrupDetayi,
      });
      NavigationService.navigate('GroupDetail');
    })
    .catch(e => {
      dispatch({
        type: GET_SELECTED_GROUP_DETAIL_FAIL,
      });
      Alert.alert('Hata', 'Beklenmedik bir hata meydana geldi.');
    });
};

export const getSelectedGroupDetail=groupUid=>dispatch=>{
派遣({
类型：获取\u所选\u组\u详细信息\u开始，
});
火基
.数据库（）
.ref（'/groups/'+groupUid）
.once（'值'）
.then（功能（快照）{
const membersList=\.map（snapshot.val（）.members，（val，uid）=>（{…val，uid}））；
let groupMembersList=\uu0.map（selectedGroupData.members，（val，uid）=>{
返回{…val，uid}；
});
for（让index=0；indexconsole.log（e.message））；
}
const yeniGrupDetayi={…snapshot.val（），uid:groupUid，membersList}；
console.log（'ACTION NE YAZDI？==>'，yeniGrupDetayi）；
派遣({
类型：获取\u所选\u组\u详细信息\u成功，
有效载荷：yeniGrupDetayi，
});
NavigationService.navigate（'GroupDetail'）；
})
.catch（e=>{
派遣({
类型：获取\u所选\u组\u详细信息\u失败，
});
警惕。警惕（'Hata'、'Beklenmedik bir Hata meydana geldi'）；
});
};

如果第二个Firebase函数将等待响应，

memberList

将位于

yeniGrupDetayi

对象内。如果第二个Firebase函数将等待响应，

membersList

将位于

yeniGrupDetayi

对象内。在操作代码的末尾，FlatList正在运行，但我无法在FlatList中看到

成员列表。
您可以提取
firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')

这样的函数的行：
async function getMembersListFromDB() {
  return firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
}

export const getSelectedGroupDetail = groupUid => dispatch => {
      dispatch({
        type: GET_SELECTED_GROUP_DETAIL_START,
      });
  firebase
      .database()
      .ref('/groups/' + groupUid)
      .once('value')
      .then(function (snapshot) {
        const membersList = _.map(snapshot.val().members, (val, uid) => ({ ...val, uid }));

        let groupMembersList = _.map(selectedGroupData.members, (val, uid) => {
          return { ...val, uid };
        });
        for (let index = 0; index < groupMembersList.length; index++) {
          firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
              .then(function (childSnapshot) {
                let name = childSnapshot.val().displayName;
                groupMembersList[index] = { ...groupMembersList[index], name };

                if(index === groupMembersList.length -1)
                {
                  const yeniGrupDetayi = { ...snapshot.val(), uid: groupUid, membersList };
                  console.log('ACTION NE YAZDI ? ===>', yeniGrupDetayi);
                  dispatch({
                    type: GET_SELECTED_GROUP_DETAIL_SUCCESS,
                    payload: yeniGrupDetayi,
                  });
                  NavigationService.navigate('GroupDetail');
                }
              })
              .catch(e => console.log(e.message));
        }
      })
      .catch(e => {
        dispatch({
          type: GET_SELECTED_GROUP_DETAIL_FAIL,
        });
        Alert.alert('Hata', 'Beklenmedik bir hata meydana geldi.');
      });
};

现在在for循环中：
for (let index = 0; index < groupMembersList.length; index++) {
  await this.getMembersListFromDB().then(function (snapshot) {
    let name = snapshot.val().displayName;
    groupMembersList[index] = { ...groupMembersList[index], name };
  })

for（让index=0；index

说明：
您可以将aysnc
与await
组合使用，暂停程序的执行，直到Promise
得到解决。关键字await
将告诉程序等待数据库查询执行，然后程序将继续执行
有关async/await的更多信息
您可以提取
firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')

这样的函数的行：
async function getMembersListFromDB() {
  return firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
}

export const getSelectedGroupDetail = groupUid => dispatch => {
      dispatch({
        type: GET_SELECTED_GROUP_DETAIL_START,
      });
  firebase
      .database()
      .ref('/groups/' + groupUid)
      .once('value')
      .then(function (snapshot) {
        const membersList = _.map(snapshot.val().members, (val, uid) => ({ ...val, uid }));

        let groupMembersList = _.map(selectedGroupData.members, (val, uid) => {
          return { ...val, uid };
        });
        for (let index = 0; index < groupMembersList.length; index++) {
          firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
              .then(function (childSnapshot) {
                let name = childSnapshot.val().displayName;
                groupMembersList[index] = { ...groupMembersList[index], name };

                if(index === groupMembersList.length -1)
                {
                  const yeniGrupDetayi = { ...snapshot.val(), uid: groupUid, membersList };
                  console.log('ACTION NE YAZDI ? ===>', yeniGrupDetayi);
                  dispatch({
                    type: GET_SELECTED_GROUP_DETAIL_SUCCESS,
                    payload: yeniGrupDetayi,
                  });
                  NavigationService.navigate('GroupDetail');
                }
              })
              .catch(e => console.log(e.message));
        }
      })
      .catch(e => {
        dispatch({
          type: GET_SELECTED_GROUP_DETAIL_FAIL,
        });
        Alert.alert('Hata', 'Beklenmedik bir hata meydana geldi.');
      });
};

现在在for循环中：
for (let index = 0; index < groupMembersList.length; index++) {
  await this.getMembersListFromDB().then(function (snapshot) {
    let name = snapshot.val().displayName;
    groupMembersList[index] = { ...groupMembersList[index], name };
  })

for（让index=0；index

说明：
您可以将aysnc
与await
组合使用，暂停程序的执行，直到Promise
得到解决。关键字await
将告诉程序等待数据库查询执行，然后程序将继续执行
关于async/await的更多信息
您的问题是，您通过循环进行了多个承诺调用，并且在循环后放置了单独的代码。问题是，代码不会等待执行，直到您将其精确化
因此，要么你将电话重新组合成一个单一的承诺，等待所有人响应，要么你这样做：
async function getMembersListFromDB() {
  return firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
}

export const getSelectedGroupDetail = groupUid => dispatch => {
      dispatch({
        type: GET_SELECTED_GROUP_DETAIL_START,
      });
  firebase
      .database()
      .ref('/groups/' + groupUid)
      .once('value')
      .then(function (snapshot) {
        const membersList = _.map(snapshot.val().members, (val, uid) => ({ ...val, uid }));

        let groupMembersList = _.map(selectedGroupData.members, (val, uid) => {
          return { ...val, uid };
        });
        for (let index = 0; index < groupMembersList.length; index++) {
          firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
              .then(function (childSnapshot) {
                let name = childSnapshot.val().displayName;
                groupMembersList[index] = { ...groupMembersList[index], name };

                if(index === groupMembersList.length -1)
                {
                  const yeniGrupDetayi = { ...snapshot.val(), uid: groupUid, membersList };
                  console.log('ACTION NE YAZDI ? ===>', yeniGrupDetayi);
                  dispatch({
                    type: GET_SELECTED_GROUP_DETAIL_SUCCESS,
                    payload: yeniGrupDetayi,
                  });
                  NavigationService.navigate('GroupDetail');
                }
              })
              .catch(e => console.log(e.message));
        }
      })
      .catch(e => {
        dispatch({
          type: GET_SELECTED_GROUP_DETAIL_FAIL,
        });
        Alert.alert('Hata', 'Beklenmedik bir hata meydana geldi.');
      });
};

export const getSelectedGroupDetail=groupUid=>dispatch=>{
派遣({
类型：获取\u所选\u组\u详细信息\u开始，
});
火基
.数据库（）
.ref（'/groups/'+groupUid）
.once（'值'）
.then（功能（快照）{
const membersList=\.map（snapshot.val（）.members，（val，uid）=>（{…val，uid}））；
let groupMembersList=\uu0.map（selectedGroupData.members，（val，uid）=>{
返回{…val，uid}；
});
for（让index=0；index'，yeniGrupDetayi）；
派遣({
类型：获取\u所选\u组\u详细信息\u成功，
有效载荷：yeniGrupDetayi，
});
NavigationService.navigate（'GroupDetail'）；
}
})
.catch（e=>console.log（e.message））；
}
})
.catch（e=>{
派遣({
类型：获取\u所选\u组\u详细信息\u失败，
});
警惕。警惕（'Hata'、'Beklenmedik bir Hata meydana geldi'）；
});
};

它有点凌乱，不易维护，但会起到一定的作用。
您的问题是，您通过循环调用了多个承诺，并且在循环后放置了单独的代码。问题是，代码不会等到您精确执行后才执行
因此，要么你将电话重新组合成一个单一的承诺，等待所有人响应，要么你这样做：
async function getMembersListFromDB() {
  return firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
}

export const getSelectedGroupDetail = groupUid => dispatch => {
      dispatch({
        type: GET_SELECTED_GROUP_DETAIL_START,
      });
  firebase
      .database()
      .ref('/groups/' + groupUid)
      .once('value')
      .then(function (snapshot) {
        const membersList = _.map(snapshot.val().members, (val, uid) => ({ ...val, uid }));

        let groupMembersList = _.map(selectedGroupData.members, (val, uid) => {
          return { ...val, uid };
        });
        for (let index = 0; index < groupMembersList.length; index++) {
          firebase.database().ref('/users/' + groupMembersList[index].uid).once('value')
              .then(function (childSnapshot) {
                let name = childSnapshot.val().displayName;
                groupMembersList[index] = { ...groupMembersList[index], name };

                if(index === groupMembersList.length -1)
                {
                  const yeniGrupDetayi = { ...snapshot.val(), uid: groupUid, membersList };
                  console.log('ACTION NE YAZDI ? ===>', yeniGrupDetayi);
                  dispatch({
                    type: GET_SELECTED_GROUP_DETAIL_SUCCESS,
                    payload: yeniGrupDetayi,
                  });
                  NavigationService.navigate('GroupDetail');
                }
              })
              .catch(e => console.log(e.message));
        }
      })
      .catch(e => {
        dispatch({
          type: GET_SELECTED_GROUP_DETAIL_FAIL,
        });
        Alert.alert('Hata', 'Beklenmedik bir hata meydana geldi.');
      });
};

export const getSelectedGroupDetail=groupUid=>dispatch=>{
派遣({
类型：获取\u所选\u组\u详细信息\u开始，
});
火基
.数据库（）
.ref（'/groups/'+groupUid）
.once（'值'）
.then（功能（快照）{
康斯特成员