firebase - 在 Firebase 函数中等待多个 Promise

Question

我试图弄清楚如何在函数结束之前等待多个 promise 被执行。

本质上，这就是我尝试做的:

如果用户删除他/她的帐户，我想清除与他/她相关的所有数据

直接数据可以删除

如果用户是组的一部分，则该组仍然存在，如果其他用户在该组中；否则该组也将被删除

这是我到目前为止尝试过的:

A) Main 函数(启动第一层 Promise):

export function cleanUpAllData(user) {
  const userId = user.uid;
  const promises = [];
  promises.push(deleteCategoriesData(userId)); // this works fine
  promises.push(deleteUserAndGroupData(userId)); // this one has other promises which still run when Promise.all() is finished
  Promise.all(promises)
    .then(() => {
      return "ok"; // this works so far, but not all promises are resolved
    })
    .catch(errPromises => {
      console.log("an error occured during the processing of main promises");
      console.log(errPromises, errPromises.code);
      return "error";
    })
}

B)deleteUserAndGroupData 函数(另一个promise 工作正常):在用户数据中找到的每个组都启动另一个级别的promise 并触发第三个级别的promise (deleteGroup) - 其余的工作正常

function deleteUserAndGroupData(userId) {
  const promisesUserData = [];

  return admin.firestore().collection('users').doc(userId).collection('groups').get()
    .then(userGroups => {
        userGroups.forEach(userGroupData => {
            // delete group data
            promisesUserData.push(deleteGroups(userId, userGroupData.id)); // here are other promises that need to be resolved - somewhere is a problem              
            // delete all Groups in Users (subcollection)
            promisesUserData.push(deleteGroupInUser(userId, userGroupData.id)); // this works fine          
        });
        Promise.all(promisesUserData)
        .then(() => {
            admin.firestore().collection('users').doc(userId).delete()
                .then(() => {
                    return "user data deleted"; // works fine
                })
                .catch(() => {
                    console.log("an error occured during deleting of user");
                    return "error";
                });
        })
        .catch(errPromises => {
            console.log("an error occured during the processing of promisesUserData");
            console.log(errPromises, errPromises.code);
            return "error";
        })
    })
    .catch(errUserGroups => {
        console.log(errUserGroups, errUserGroups.code);
        return "no groups in User";
    });
}

C)deleteGroups 函数:删除组中的子集合(工作正常)，然后如果没有其他用户(不起作用)，则应删除该组

function deleteGroups(userId,groupId) {
  const promisesDeleteGroups = [];
  // delete groups subcollection data 
  promisesDeleteGroups.push(deleteGroupRole(userId, groupId));
  promisesDeleteGroups.push(deleteGroupUser(userId, groupId));

  return Promise.all(promisesDeleteGroups).then(() => {
    checkForOthers(groupId);
  }).catch(errDeleteGroupSubcollections => {
    console.log("an error occured during the processing of promisesDeleteGroups");
    console.log(errDeleteGroupSubcollections, errDeleteGroupSubcollections.code);
    return "error";
  });
}

D) checkForOthers 函数 - 检查子集合中是否有任何条目并应开始删除该组(但不会)

function checkForOthers(groupId) {
  return admin.firestore().collection('groups').doc(groupId).collection('users').get()
    .then(groupUsers => {
        return "other users exist - group should not be deleted";
    })
    .catch(errGroupUsers => {
        // console.log("no other group members - group can be deleted");
        // return "no other group members - group can be deleted";
        console.log(errGroupUsers, errGroupUsers.code);
        checkForInvitesAndDelete(groupId);
    });;
}

E) checkForInvitesAndDelete:首先我想删除另一个可能存在也可能不存在的子集合，如果另一个用户已被邀请加入该组；那么它应该触发最后的组删除(这似乎不起作用)

function checkForInvitesAndDelete(groupId) {
  const promisesInvitesAndDelete = [];
  return admin.firestore().collection('groups').doc(groupId).collection('invitations').get()
    .then(groupInvitations => {
        console.log("delete open Group Invitations");
        groupInvitations.forEach(groupInvite => {
            promisesInvitesAndDelete.push(deleteGroupInvite(groupId, groupInvite.id));
        });
        Promise.all(promisesInvitesAndDelete)
            .then(() => {
                deleteGroup(groupId)
            })
            .catch(errPromisesInvitesAndDelete => {
                console.log("an error occured during the processing of deleting group invites");
                console.log(errPromisesInvitesAndDelete, errPromisesInvitesAndDelete.code);
                return "error";
            });
    })
    .catch(() => {
        console.log("no open invitations");
        deleteGroup(groupId);
    });
}

F) deleteGroup 函数

function deleteGroup(groupId) {
  return admin.firestore().collection('groups').doc(groupId).delete();
}

我对编程比较陌生，尤其是 Firebase 函数，所以任何帮助将不胜感激!!

谢谢!

Answer 1

您没有使用 return关键字无处不在，应该在哪里。如果你做 async任务，你必须' return '它有点。

一些例子:

示例 A:添加 return之前 Promise.all(promises)
... B: 添加 return之前 Promise.all(promisesUserData)
... C:添加 return之前 checkForOthers(groupId)
... D:添加 return之前 checkForInvitesAndDelete(groupId)
... E:添加 return之前 Promise.all(promisesInvitesAndDelete)和 deleteGroup(groupId)