Firebase函数抛出错误:返回未定义的、预期的Promise或值.我该如何解决此问题

Question

这是我的.ts文件，我使用then方法和catch块来处理最终返回语句中的错误。这是一个由Firestore触发的后台函数，在创建文档时，我基本上要做3件事1.将数据复制到Firestore中的另一个文档2.发送FCM通知3.创建一个名为"notificationObject"的JSON对象，并将其添加到Firestore 的另一个文档中

import * as functions from 'firebase-functions'
const admin = require('firebase-admin')
//When client followes a user, a firestore .onCreate() background function is triggered to
//1.add follower to the followee's followers sub collection
//2.an FCM notification to sent to the users
//3.A Notification doc is added to Notification Sub Collection
export const addTheNewFollower = functions.region('asia-east2').firestore.document
('Users/{followerUserId}/following/{followeeUserId}').onCreate((data, context) => {
//get follower and followee Uids for identification
const followeeUid = context.params.followeeUserId
//for identification and notification payload data (Intent Extras for client)
const followerUid = context.params.followerUserId
//Get Follower user details that needs to be duplicated to the Followee's following Sub Coll
//And also added to the notification Payload data
admin.firestore().collection('Users').doc(followerUid).get().then((doc:{ exists: any; data: () =>         
any }) => {
//Extracting this separately as this need not be copied to the Followers sub-collection
const followerImageUrl = doc.data().DOWNLOAD_URL
//This data will be copied to the followers sub collection
const followerData = {
name:  doc.data().name,
uid: followerUid,
userName: doc.data().userName,
}

//get the notification token of the followee to identify & send notification to his device
admin.firestore().collection('Users').doc(followeeUid).collection('notificationToken')
.doc('theNotificationToken').get().then((notificationTokenDoc:{ exists: any; data: () => any })     
=> {
const followeeNotificationToken = notificationTokenDoc.data().notificationToken
//Create the Notification Payload content
const notificationPayload = {
notification: {
title: 'You have a new follower!',
body: `${followerData.userName}`,
clickAction: ".People.PersonProfileActivity",
image: `${followerImageUrl}`
},
data: {
ACTIVITY_NAME: "PersonProfileActivity",
//The below field name to be same as the one used in the client
PERSON_UID_INTENT_EXTRA: followerUid,
PERSON_NAME_INTENT_EXTRA: followerData.name,
PERSON_USERNAME_INTENT_EXTRA: followerData.userName,
//If the app is in the foreground then this channel will be used to trigger a notification and this     
//channel has to
//be created at the client else, this will fail
CHANNEL_ID: "Follow Update ID"
}
}
//random 11 digital Notification Doc Id
const randomNotificationDocId = (Math.random() * 100000000000).toString()
const notificationObject = {
message:`${followerData.userName} started following you`,
receivedTime: Date.now(),
//This is needed for client to access this doc and update the wasClicked field
notificationDocId: randomNotificationDocId,
senderName: followerData.name,
senderUid: followerData.uid,
//this will be false by default, will turn true at client when clicked
wasClicked: false,
//this type has to be same as in the client
notificationChannelId: "Follow Updates",
intentToActivity: "PersonProfileActivity",
intentExtrasUid: followerData.uid,
intentExtrasName: followerData.name,
intentExtrasUserName: followerData.userName,
}
//Add the follower to the followee sub-collection
admin.firestore().collection('Users').doc(followeeUid).collection('followers').doc(followerUid)
.set(followerData)
//Add the notification doc to the user's notification sub collection
admin.firestore().collection('Users').doc(followeeUid).collection('Notifications')
.doc(randomNotificationDocId).set(notificationObject)
//Send the notification to the user
return admin.messaging().sendToDevice(followeeNotificationToken,     
notificationPayload).then(function(response: any) {
console.log("Successfully sent message:", response);
})
.catch(function(error: any) {
console.log("Error sending message:", error);
})
})
})
})

函数按预期完成，但我在Firebase控制台上得到了"function return undefined，expected Promise or value"。有人能告诉我我在这里做错了什么吗

Answer 1

试试这个：

Return Promise.all([
admin.firestore().collection('Users').doc(followeeUid).collection('followers').doc(followerUid).set(followerData)
admin.firestore().collection('Users').doc(followeeUid).collection('Notifications').doc(randomNotificationDocId).set(notificationObject)
admin.messaging().sendToDevice(followeeNotificationToken, notificationPayload)
])

如果要更新Firestore或实时数据库中的更多字段，请将它们放在此return Promise.all([ ... ])语句中。

Answer 2

好的，所以我在这个文件中总共有5个方法。我不得不使用"then(("方法将其中的2个方法链接起来，并将底部的3个方法添加到一个名为promise的数组中，然后使用promise.all(promise(命令将它们作为promise返回。

这是我的最终代码

export const addTheNewFollower = functions.region('asia-east2').firestore.document
('Users/{followerUserId}/following/{followeeUserId}').onCreate((data, context) => {

//get follower and followee Uids for identification
const followeeUid = context.params.followeeUserId
//for identification and notification payload data (Intent Extras for client)
const followerUid = context.params.followerUserId
//Get Follower user details that needs to be duplicated to the Followee's following 
//Sub Coll
//And also added to the notification Payload data
return admin.firestore().collection('Users').doc(followerUid).get().then((doc:{ 
exists: any; data: () => any }) => {
//Extracting this separately as this need not be copied to the Followers sub-    
//collection
const followerImageUrl = doc.data().DOWNLOAD_URL
//This data will be copied to the followers sub collection
const followerData = {
name:  doc.data().name,
uid: followerUid,
userName: doc.data().userName,
}

//get the notification token of the followee to identify & send notification to his 
//device
return admin.firestore().collection('Users').doc(followeeUid)
.collection('notificationToken')
.doc('theNotificationToken').get().then((notificationTokenDoc:{ exists: any; data: () 
=> any }) => {
const followeeNotificationToken = notificationTokenDoc.data().notificationToken
//Create the Notification Payload content
const notificationPayload = {
notification: {
title: 'You have a new follower!',
body: `${followerData.userName}`,
clickAction: ".People.PersonProfileActivity",
image: `${followerImageUrl}`
},
data: {
ACTIVITY_NAME: "PersonProfileActivity",
//The below field name to be same as the one used in the client
PERSON_UID_INTENT_EXTRA: followerUid,
PERSON_NAME_INTENT_EXTRA: followerData.name,
PERSON_USERNAME_INTENT_EXTRA: followerData.userName,
//If the app is in the foreground then this channel will be used to trigger a 
notification and this channel has to
//be created at the client else, this will fail
CHANNEL_ID: "Follow Update ID"
}
}
//random 11 digital Notification Doc Id
const randomNotificationDocId = (Math.random() * 100000000000).toString()
const notificationObject = {
message:`${followerData.userName} started following you`,
receivedTime: Date.now(),
//This is needed for client to access this doc and update the wasClicked field
notificationDocId: randomNotificationDocId,
senderName: followerData.name,
senderUid: followerData.uid,
//this will be false by default, will turn true at client when clicked
wasClicked: false,
//this type has be same as in the client
notificationChannelId: "Follow Updates",
intentToActivity: "PersonProfileActivity",
intentExtrasUid: followerData.uid,
intentExtrasName: followerData.name,
intentExtrasUserName: followerData.userName,
}

const promises = []
//Add the follower to the followee sub-collection
const p = admin.firestore().collection('Users').doc(followeeUid)
.collection('followers').doc(followerUid).set(followerData)
promises.push(p)
//Add the notification doc to the user's notification sub collection
const p1 = admin.firestore().collection('Users').doc(followeeUid)
.collection('Notifications').doc(randomNotificationDocId).set(notificationObject)
promises.push(p1)
//Send the notification to the user
const p2 = admin.messaging().sendToDevice(followeeNotificationToken, 
notificationPayload)
promises.push(p2)
return Promise.all(promises)
})
})
})