The right solution for promises - javascript

I have the app on node.js with connecting to firebase. I need to update the data correctly.
How to call the function getOrSetUserTrackDay(day) in a promise to get a good value, but not undefined?
let userData = [];
let userID = req.params.userID;
let today = req.params.today;
let yesterday = req.params.yesterday;
db.collection('users').doc(userID).get()
.then((userDataFromDB) => {
if (!userDataFromDB.exists) {
res.status(404).send('User not found');
}
else {
function getOrSetUserTrackDay(day) {
let userTrackRef = db.collection('history').doc('daily').collection(day).doc(userID);
userTrackRef.get()
.then(userTrackData => {
if (userTrackData.exists) {
return userTrackData.data(); // good
}
else {
let userNewData = {
username: userDataFromDB.data().username,
photoUrl: userDataFromDB.data().photoUrl
};
userTrackRef.update(userNewData);
return userNewData; // good
}
})
}
userData = {
user: userDataFromDB.data(),
today: getOrSetUserTrackDay(today), // undefined
yesterday: getOrSetUserTrackDay(yesterday) // undefined
};
res.json(userData);
}
})
.catch((err) => {
console.log(err);
res.status(404).send(err);
});

well getOrSetUserTrackDay has no return statement, hence it returns undefined - but, since it contains asynchronous code, you'll never be able to use it synchronously
So, you can do the following
let userData = [];
let userID = req.params.userID;
let today = req.params.today;
let yesterday = req.params.yesterday;
db.collection('users').doc(userID).get()
.then((userDataFromDB) => {
if (!userDataFromDB.exists) {
res.status(404).send('User not found');
}
else {
let getOrSetUserTrackDay = day => {
let userTrackRef = db.collection('history').doc('daily').collection(day).doc(userID);
return userTrackRef.get()
.then(userTrackData => {
if (userTrackData.exists) {
return userTrackData.data(); // good
} else {
let userNewData = {
username: userDataFromDB.data().username,
photoUrl: userDataFromDB.data().photoUrl
};
userTrackRef.update(userNewData);
return userNewData; // good
}
});
};
Promise.all([getOrSetUserTrackDay(today), getOrSetUserTrackDay(yesterday)])
.then(([today, yesterday]) => res.json({
user: userDataFromDB.data(),
today,
yesterday
}));
}
}).catch((err) => {
console.log(err);
res.status(404).send(err);
});
Note: changed getOrSetUserTrackDay from a function declaration to a function expression (in this case, an arrow function for no particular reason) - because Function declarations should not be placed in blocks. Use a function expression or move the statement to the top of the outer function.

Related

typescript node insert on mongodb database

im a total newbie in js (typescript, mongoDB, node.)
i just found that my code is not behaving as i expected, im getting 6 registers on the mongoDB instead of just one, it should check if the register exists and then update it, i dont know if it is something related to the await / async or i am doing something wrong, thanks in advace, here is my code.
fields.forEach((value) => {
try {
const mongoConnection = new DocumentDbRepository();
let checksIfExists = await mongoConnection.getValue(key, information[uniqueValue]);
if(checksIfExists==null){
let insert = await mongoConnection.insertValue(information);
console.log(insert);
}
if(checksIfExists?.passValue===information.passValue){
console.log('---------update---------');
let sons = Object.values(information.ticketToRide);
information.ticketToRide = sons;
let update = await mongoConnection.updateRegister(information, checksIfExists._id);
console.log(update);
} else {
console.log('---------insert---------');
let sons = Object.values(information.ticketToRide);
information = sons;
let insert = await mongoConnection.insertValue(information);
console.log(insert);
}
} catch (error) {
console.log(error)
}
}
async getValue(uniqueValue: any, keyValue:any) {
if (this._connection == null) {
await this.connect();
}
const db = this._connection.db(DocumentDbRepository.DbName);
const ticketToRide = db.collection("ticketToRide");
const query = {};
query[uniqueValue] = ''+keyValue+'';
const passInfo = await ticketToRide.findOne(query);
return passInfo;
}
async insertValue(information: any) {
if (this._connection == null) {
await this.connect();
}
const db = this._connection.db(DocumentDbRepository.DbName);
const ticketToRide = db.collection("ticketToRide");
let check = await ticketToRide.insertOne(
information
)
return check;
}
First, you don't need to create a connection inside the loop.
Second, mongodb has an update() or updateMany() method that has a special option { upsert: true }. If it is passed, insert will happen automatically.
Usage example:
Person.update( { name: 'Ted' }, { name: 'Ted', age : 50 }, { upsert: true })

onRequest vs onCall returning null

Please help me figure out the difference in return behaviour between the onCall and onRequest google functions below.
onCall, the problem: returns null on all returns, except at the first return (as commented below). The db entries and rest of the code works fine. Just no returns problem.
onRequest, returns perfectly fine on every return. The db entries and rest of the code also works fine.
Both as you will see compare the same, but I just can't seem to get it to work at all. Any advice on how to get my returns to work for the onCall (and structure it better) would be much appreciated.
I am keen on sticking with async await (as opposed to a promise). Using Node.js 12. I am calling the onCall in Flutter, don't know if that is relevant for the question.
The onCall:
exports.applyUserDiscount = functions.https.onCall(async (data, context) => {
if (!context.auth) return {message: "Authentication Required!", code: 401};
const uid = context.auth.uid;
const discountCode = data["discountCode"];
const cartTotal = data["cartTotal"];
try {
return await db.collection("discountCodes").where("itemID", "==", discountCode).limit(1).get()
.then(async (snapshot) => {
if (snapshot.empty) {
return "doesNotExist"; // The only return that works.
} else { // Everything else from here onwards returns null.
snapshot.forEach(async (doc) => {
if (doc.data().redeemed == true) {
return "codeUsed";
} else {
const newCartTotal = cartTotal - doc.data().discountAmount;
if (newCartTotal < 0) {
return "lessThanTotal";
} else {
doc.ref.update({
redeemed: true,
uid: uid,
redeemDate: fireDateTimeNow,
});
await db.collection("userdata").doc(uid).set({
cartDiscount: admin.firestore.FieldValue.increment(-doc.data().discountAmount),
}, {merge: true});
return doc.data().discountAmount.toString();
}
}
});
}
});
} catch (error) {
console.log("Error:" + error);
return "error";
}
});
The onRequest:
exports.applyUserDiscount = functions.https.onRequest(async (req, res) => {
const uid = req.body.uid;
const discountCode = req.body.discountCode;
const cartTotal = req.body.cartTotal;
try {
return await db.collection("discountCodes").where("itemID", "==", discountCode).limit(1).get()
.then(async (snapshot) => {
if (snapshot.isempty) {
res.send("doesNotExist");
} else {
snapshot.forEach(async (doc) => {
if (doc.data().redeemed == true) {
res.send("codeUsed");
} else {
const newCartTotal = cartTotal - doc.data().discountAmount;
if (newCartTotal < 0) {
res.send("lessThanTotal");
} else {
doc.ref.update({
redeemed: true,
uid: uid,
redeemDate: fireDateTimeNow,
});
await db.collection("userdata").doc(uid).set({
cartDiscount: admin.firestore.FieldValue.increment(-doc.data().discountAmount),
}, {merge: true});
res.send(doc.data().discountAmount.toString());
}
}
});
}
});
} catch (error) {
console.log(error);
res.send("error");
}
});
There are several points to be noted when looking at your code(s):
You should not use async/await within a forEach loop. The problem is that the callback passed to forEach() is not being awaited, see more explanations here or here. HOWEVER, in your case you don't need to loop over the QuerySnapshot since it contains only one doc. You can use the docs property which return an array of all the documents in the QuerySnapshot and take the first (and unique) element.
You mix-up then() with async/await, which is not recommended.
I would advise to throw exceptions for the "error" cases, like doesNotExist, codeUsed or lessThanTotal but it's up to you to choose. The fact that, for example, the lessThanTotal case is an error or a standard business case is debatable... So if you prefer to send a "text" response, I would advise to encapsulate this response in a Object with one property: in your front-end the response will always have the same format.
So, the following should do the trick. Note that I send back on object with a response element, including for the cases that could be considered as errors. As said above you could throw an exception in these cases.
exports.applyUserDiscount = functions.https.onCall(async (data, context) => {
if (!context.auth) ... //See https://firebase.google.com/docs/functions/callable#handle_errors
const uid = context.auth.uid;
const discountCode = data["discountCode"];
const cartTotal = data["cartTotal"];
try {
const snapshot = await db.collection("discountCodes").where("itemID", "==", discountCode).limit(1).get();
if (snapshot.empty) {
//See https://firebase.google.com/docs/functions/callable#handle_errors
} else {
const uniqueDoc = snapshot.docs[0];
if (uniqueDoc.data().redeemed == true) {
return { response: "codeUsed" };
} else {
const newCartTotal = cartTotal - uniqueDoc.data().discountAmount;
if (newCartTotal < 0) {
return { response: "lessThanTotal" };
} else {
await uniqueDoc.ref.update({ // See await here!!
redeemed: true,
uid: uid,
redeemDate: fireDateTimeNow,
});
await db.collection("userdata").doc(uid).set({
cartDiscount: admin.firestore.FieldValue.increment(-uniqueDoc.data().discountAmount),
}, { merge: true });
return {
response: uniqueDoc.data().discountAmount.toString()
}
}
}
}
} catch (error) {
console.log("Error:" + error);
return "error";
}
});

Stripe functions returning calls after function finished

Relatively new to Javascript however, i'm trying to work with Stripe and my way around a user submitting another payment method and then paying an invoice with that method. if the payment fails again - it should remove the subscription alltogether. I'm using Firebase Realtime Database with GCF & Node.js 8.
Here is what i have so far
exports.onSecondPaymentAttempt = functions.database.ref("users/{userId}/something/somethingHistory/{subDbId}/newPayment").onCreate((snapshot, context)=>{
var s = snapshot.val();
var fields = s.split(",");
const cardToken = fields[0];
const cus_id = fields[1];
const conn_id = fields[2];
const subDbId = context.params.subDbId;
const userId = context.params.userId;
return stripe.customers.createSource(
cus_id,
{source: cardToken},{
stripeAccount: `${conn_id}`,
},
(err, card)=> {
console.log(err);
if(err){
return console.log("error attaching card "+ err)
}else{
const invoiceNo = admin.database().ref(`users/${userId}/something/somethingHistory/${subDbId}`)
return invoiceNo.once('value').then(snapshot=>{
const invoiceNumber = snapshot.child("invoiceId").val();
const subId = snapshot.child("subscriptionId").val();
return stripe.invoices.pay(
invoiceNumber,
{
expand: ['payment_intent','charge','subscription'],
},{
stripeAccount: `${conn_id}`,
},
(err, invoice)=>{
if(err){
return console.log("error paying invoice "+ err)
}else{
if(invoice.payment_intent.status==="succeeded"){
//DO SOME CODE
return console.log("New Payment succeeded for "+invoiceNumber)
}else{
//DO SOME OTHER CODE
//CANCEL
return stripe.subscriptions.del(
subId,{
stripeAccount: `${conn_id}`,
},
(err, confirmation)=> {
if(err){
return console.log("Subscription error")
}else{
return console.log("Subscription cancelled")
}
});
}
}
});
})
}
});
To me it looks like an incredibly inefficient / ugly way of achieving the effect and overall the user is sitting waiting for a response for approx 15 seconds although the function finishes its execution after 1862ms - I still get responses up to 5 - 10 seconds after.
What's the most efficient way of achieving the same desired effect of registering a new payment source, paying subscription and then handling the result of that payment?
You should use the Promises returned by the Stripe asynchronous methods, as follows (untested, it probably needs some fine tuning, in particular with the objects passed to the Stripe methods):
exports.onSecondPaymentAttempt = functions.database.ref("users/{userId}/something/somethingHistory/{subDbId}/newPayment").onCreate((snapshot, context) => {
var s = snapshot.val();
var fields = s.split(",");
const cardToken = fields[0];
const cus_id = fields[1];
const conn_id = fields[2];
const subDbId = context.params.subDbId;
const userId = context.params.userId;
return stripe.customers.createSource(
//Format of this object to be confirmed....
cus_id,
{ source: cardToken },
{ stripeAccount: `${conn_id}` }
)
.then(card => {
const invoiceNo = admin.database().ref(`users/${userId}/something/somethingHistory/${subDbId}`)
return invoiceNo.once('value')
})
.then(snapshot => {
const invoiceNumber = snapshot.child("invoiceId").val();
const subId = snapshot.child("subscriptionId").val();
return stripe.invoices.pay(
invoiceNumber,
{ expand: ['payment_intent', 'charge', 'subscription'] },
{ stripeAccount: `${conn_id}` }
)
})
.then(invoice => {
if (invoice.payment_intent.status === "succeeded") {
//DO SOME CODE
console.log("New Payment succeeded for " + invoiceNumber)
return null;
} else {
//DO SOME OTHER CODE
//CANCEL
return stripe.subscriptions.del(
subId, {
stripeAccount: `${conn_id}`,
});
}
})
.catch(err => {
//....
return null;
})
});
I would suggest you watch the three videos about "JavaScript Promises" from the official Firebase video series, which explain why it is key to correctly chain and return the promises returned by the asynchronous methods.

Having a promise issue with my google cloud function

I have an http trigger in cloud functions that is working, however I am getting some logs come back in a weird order. I am pretty sure I have not executed the promises correctly.
here is the code:
exports.createGame = functions.https.onRequest((req, res) => {
return cors(req, res, () => {
// Check for POST request
if (req.method !== "POST") {
res.status(400).send('Please send a POST request');
return;
}
const createGame = admin.firestore().collection('games')
generatePin()
function generatePin() {
...pin generating code goes here...
addGame(newGidToString)
}
function addGame(newGidToString) {
var getGame = admin.firestore().collection('games')
getGame = getGame.where('gid', '==', newGidToString)
getGame.get().then(snapshot => {
if (snapshot.empty) {
console.log('BODY ', req.body)
const promises = [];
const gameTitle = req.body.gametitle
const targetGID = req.body.target
const numPlayers = req.body.playercount.toString()
const newGID = newGidToString
const collections = ['games', 'clues', 'detours', 'messages', 'questions', 'tagstate']
collections.forEach(function (element) {
console.log('start loop', element)
let elementsRef = admin.firestore().collection(element)
elementsRef = elementsRef.where('gid', '==', targetGID)
elementsRef.get().then(snapshot => {
var batch = admin.firestore().batch()
snapshot.forEach(function (doc) {
// change the gid to the new game gid
let data = doc.data()
data.gid = newGID
if(data.template){
data.template = false
}
if(!data.parent) {
data.parent = targetGID
}
if (!data.playercount) {
data.playercount = numPlayers
}
if (data.gametitle) {
data.gametitle = gameTitle
}
let elementRef = admin.firestore().collection(element).doc()
batch.set(elementRef, data)
})
batch.commit().then(data => {
console.log('complete batch ', element)
})
})
})
res.send({ status: 200, message: 'Game: added.', pin: newGID})
console.log('completed');
} else {
console.log('found a match ', snapshot)
// re-run the generator for a new pin
generatePin()
}
})
}
})
})
Here is a screen shot of the console logs.
Notice the order of the logs. It would seem logical that completed would come at the end fo the loops.
Any help is great appreciated.
UPDATE:
function addGame(newGidToString) {
var getGame = admin.firestore().collection('games')
getGame = getGame.where('gid', '==', newGidToString)
getGame.get().then(snapshot => {
if (snapshot.empty) {
console.log('BODY ', req.body)
const promises = [];
const gameTitle = req.body.gametitle
const targetGID = req.body.target
const numPlayers = req.body.playercount.toString()
const newGID = newGidToString
const collections = ['games', 'clues', 'detours', 'messages', 'questions', 'tagstate']
collections.forEach(function (element) {
console.log('start loop', element)
let elementsRef = admin.firestore().collection(element)
elementsRef = elementsRef.where('gid', '==', targetGID)
// elementsRef.get().then(snapshot => {
const promGet = elementsRef.get(); //lets get our promise
promises.push(promGet); //place into an array
promGet.then(snapshot => { //we can now continue as before
var batch = admin.firestore().batch()
snapshot.forEach(function (doc) {
// change the gid to the new game gid
let data = doc.data()
data.gid = newGID
if(data.template){
data.template = false
}
if(!data.parent) {
data.parent = targetGID
}
if (!data.playercount) {
data.playercount = numPlayers
}
if (data.gametitle) {
data.gametitle = gameTitle
}
let elementRef = admin.firestore().collection(element).doc()
batch.set(elementRef, data)
})
batch.commit().then(data => {
console.log('complete batch ', element)
})
})
})
Promise.all(promises).then(() => {
res.send({ status: 200, message: 'Game: added.', pin: newGID })
console.log('completed');
});
// res.send({ status: 200, message: 'Game: added.', pin: newGID})
// console.log('completed');
} else {
console.log('found a match ', snapshot)
// re-run the generator for a new pin
generatePin()
}
})
}
SECOND UPDATE: (based off Keith's answer)
function addGame(newGidToString) {
var getGame = admin.firestore().collection('games')
getGame = getGame.where('gid', '==', newGidToString)
getGame.get().then(snapshot => {
if (snapshot.empty) {
console.log('BODY ', req.body)
const gameTitle = req.body.gametitle
const targetGID = req.body.target
const numPlayers = req.body.playercount.toString()
const newGID = newGidToString
const promises = [];
const collections = ['games', 'clues', 'detours', 'messages', 'questions', 'tagstate']
collections.forEach(function (element) {
console.log('start loop', element)
let elementsRef = admin.firestore().collection(element)
elementsRef = elementsRef.where('gid', '==', targetGID)
const getPromise = elementsRef.get(); //lets get our promise
promises.push(getPromise); //place into an array
getPromise.then(snapshot => { //we can now continue as before
var batch = admin.firestore().batch()
snapshot.forEach(function (doc) {
// change the gid to the new game gid
let data = doc.data()
data.gid = newGID
if(data.template){
data.template = false
}
if(!data.parent) {
data.parent = targetGID
}
if (!data.playercount) {
data.playercount = numPlayers
}
if (data.gametitle) {
data.gametitle = gameTitle
}
let elementRef = admin.firestore().collection(element).doc()
batch.set(elementRef, data)
})
batch.commit()
})
})
Promise.all(promises).then(() => {
res.send({ status: 200, message: 'Game: added.', pin: newGID })
console.log('completed from promise');
});
} else {
console.log('found a match ', snapshot)
// re-run the generator for a new pin
generatePin()
}
})
}
When looping with promises, one thing to remember is if you do a forEach, it's not going to wait.
It appears that what the OP wants to do is before he hits the complete, and does a res send, wants to make sure all promises have been completed.
Promise.all https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all , is exactly what this does.
So every time you create a promise if you push this onto an array, we can later use Promise.all to make sure all the promises are complete.
So if we replace
elementsRef.get().then(snapshot => {
with
const promGet = elementsRef.get(); //lets get our promise
promises.push(promGet); //place into an array
promGet.then(snapshot => { //we can now continue as before
Your promise is now stored for later so that Promise.all can check to make sure everything has complete. You could do this in one line, but I feel it's easier to see what's happening this way. eg->
promises.push(promGet.then(snapshot => {
Finally now we have got our promise array, before we do our res.send, lets make sure they have all completed.
Promise.all(promises).then(() => {
res.send({ status: 200, message: 'Game: added.', pin: newGID})
console.log('completed');
});
One thing to keep in mind when using Promises this way, is that you have a fair few things going on at the same time, sometimes this can be an issue, eg. connected to some service might put restrictions on the number of concurrent connections etc. So in these cases it might be an idea doing things in series or a mix of both. There are even libs that can do concurrecy, eg. Do only X amounts of promises at a time.
And finally, if you can use async / await, I'd advice using them, as it makes Promises so much nicer to work with.

Removing Percent Encoding from Firebase Cloud Functions

The firebase function I'm currently using retrieves data from a certain branch in the database where the value may or may not have percent encoding. The value is a user's username and it's encoded if there's a '.' in the name. When the user gets a notification, it has their name in the body of it, and I'm trying to figure out how to removePercentEncoding if necessary. My cloud function:
exports.newPost = functions.database.ref('/{school}/posts').onWrite((change, context) => {
const school = context.params.school
const postUsername = admin.database().ref('/{school}/lastPost/lastPostUser').once('value')
var db = admin.database();
var val1, val2;
db.ref(`/Herrick Middle School/lastPost/lastPostUser`).once('value').then(snap => {
val1 = snap.val();
console.log(snap.val());
return val1
}).then(() => {
return db.ref("test2/val").once('value');
}).catch(err => {
console.log(err);
});
return loadUsers().then(users => {
let tokens = [];
for (let user of users) {
tokens.push(user.pushToken);
console.log(`pushToken: ${user.pushToken}`);
}
let payload = {
notification: {
title: school,
body: `${val1} just posted something.`,
sound: 'Apex',
badge: '1'
}
};
return admin.messaging().sendToDevice(tokens, payload);
});
});
function loadUsers() {
let dbRef = admin.database().ref('/Herrick Middle School/regisTokens');
let defer = new Promise((resolve, reject) => {
dbRef.once('value', (snap) => {
let data = snap.val();
let users = [];
for (var property in data) {
users.push(data[property]);
console.log(`data: ${property}`);
}
resolve(users);
}, (err) => {
reject(err);
});
});
return defer;
}
More specifically, I was hoping someone could shed some light on how to remove encoding from
val
Thanks in advance.
not sure i understand but either native JS decodeURI() or regex like this
var encoded = "john%doe%doe%bird";
console.log(encoded.replace(/%/g, "."));

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