How do I query Firestore all documents today date? - node.js

Question

I am trying to generate report at a fixed schedule. But I am having a problem where I cannot retrieve the date for today onwards until the current time where the function will run.
exports.generateReport = functions.pubsub.schedule('36 15 * * *').onRun(async (context) => {
console.log(context);
const currentTime = admin.firestore.Timestamp.now();
const shopSnapshot = await db.collection("shops").get();
let shopDoc = shopSnapshot.docs.map(doc => doc.data());
const promises = [];
let transactionList = [];
let reportList = [];
let i = 0;
console.log(shopDoc);
shopDoc = shopDoc.filter(shop => !!shop.key);
console.log(shopDoc);
for(var j=0; j<shopDoc.length; j++){
console.log("Enter shop ID:"+shopDoc[j].key);
promises.push(db.collection("shops").doc(shopDoc[j].key).collection("transactions").get());
}
const snapshotArrays = await Promise.all(promises);
snapshotArrays.forEach(snapArray => {
snapArray.forEach(snap => {
//console.log(snap.data());
transactionList.push({data: snap.data(), key: shopDoc[i].key});
})
i++;
});
for(var k=0; k<shopDoc.length; k++){
let amount = 0;
for (var l=0; l<transactionList.length; l++){
if(shopDoc[k].key === transactionList[l].key){
console.log("get date");
if (transactionList[l].data.createAt < currentTime){
amount += transactionList[l].data.amount;
console.log(amount);
}
}
}
reportList.push({amount: amount, key: shopDoc[k].key});
}
console.log(reportList);
console.log(transactionList);
});
I tried using new Date() also compared with a string of date exactly the same as Firestore Timestamp format but still all transaction appear before the time or no transaction is included at this time.

Answer 1

If I correctly understand that you want to generate a daily report for all the transactions that occurred yesterday by running a schedule Cloud Function today at 00:05 for example, here is a possible approach using the moment.js library:
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const moment = require('moment');
admin.initializeApp();
exports.generateReport = functions.pubsub.schedule('05 00 * * *').onRun(async (context) => {
let m1 = moment();
let m2 = moment();
m1.add(-1, 'days');
m2.add(-1, 'days');
m1.startOf('day');
m2.endOf('day');
const shopSnapshot = await db.collection("shops").get();
let shopDoc = shopSnapshot.docs.map(doc => doc.data());
const promises = [];
let transactionList = [];
let reportList = [];
let i = 0;
shopDoc = shopDoc.filter(shop => !!shop.key);
console.log(shopDoc);
for(var j=0; j<shopDoc.length; j++){
console.log("Enter shop ID:"+shopDoc[j].key);
promises.push(
db.collection("shops")
.doc(shopDoc[j].key)
.collection("transactions")
.orderBy("createAt")
.where("createAt", ">", m1.toDate())
.where("createAt", "<=", m2.toDate())
.get()
);
}
const snapshotArrays = await Promise.all(promises);
snapshotArrays.forEach(snapArray => {
snapArray.forEach(snap => {
//console.log(snap.data());
transactionList.push({data: snap.data(), key: shopDoc[i].key});
})
i++;
});
for(var k=0; k<shopDoc.length; k++){
let amount = 0;
for (var l=0; l<transactionList.length; l++){
if(shopDoc[k].key === transactionList[l].key){
amount += transactionList[l].data.amount;
}
}
reportList.push({amount: amount, key: shopDoc[k].key});
}
//.....
});
So, what do we do in this code?
First we create two moment objects and we set their date to yesterday. Then, with startOf() and endOf() we adjust the time of the first one to yesterday at 12:00:00.000 am (i.e. 00:00:00, see here) and the second one to yesterday at 11:59:59.999 pm (i.e. 23:59:59).
With these two dates, for each transactions collection, we adapt the query as follows, calling the toDate() method:
db.collection("shops")
.doc(shopDoc[j].key)
.collection("transactions")
.orderBy("createAt")
.where("createAt", ">", m1.toDate())
.where("createAt", "<=", m2.toDate())
.get();
And that's it. The big advantage here, is that the filtering is done in the Firestore database (in the back-end), not in the front-end as you did in your question (if (transactionList[l].data.createAt < currentTime){...})