MongoDB aggregation returns empty array with NodeJS - node.js

Question

I want to create a script which is taking the average of the Volume for last 7(for example) days.
I'm stuck with aggregation stages since first stage I need to take Date for last 7 days and in second stage calculate Average of Volume
Package list:
Node-schedule - */1 * * * * (Runs the script every minute)
Binance API - Taking data from them.
Screenshot for showcasing how the document looks like in MongoDB.
Aggregation part of the Code.
const average = await dbo.collection(symbol).aggregate([{
'$match': {
'Date': { '$gte': new Date((new Date().getTime() - (7 * 24 * 60 * 60 * 1000))) }
},
},
{
'$group': {
_id: null,
'Volume': { '$avg': '$Volume' }
},
}
]).toArray();
This code returns me an empty array in terminal like this > []
Full Code here.
const { MongoClient } = require('mongodb');
const schedule = require('node-schedule');
const fetch = require("node-fetch");
const symbols = ["ADABTC", "AEBTC", "AIONBTC", "ALGOBTC", "ARDRBTC"];
//a descriptive name helps your future self and others understand code easier
const getBTCData = async symbol => { //make this function accept the current symbol
//async/await lets us write this much nicer and with less nested indents
let data = await fetch(`https://api.binance.com/api/v3/klines?symbol=${symbol}&interval=30m&limit=1`).then(res => res.json());
const btcusdtdata = data.map(d => {
return {
Open: parseFloat(d[1]),
High: parseFloat(d[2]),
Low: parseFloat(d[3]),
Close: parseFloat(d[4]),
Volume: parseFloat(d[5]),
Timespan: 30,
}
});
console.log(btcusdtdata);
saveToDatebase(symbol, btcusdtdata);
//recursive functions are complicated, we can get rid of it here
//by moving the responsibility to the caller
};
//helper function for an awaitable timeout
const sleep = ms => new Promise(res => setTimeout(res, ms));
const j = schedule.scheduleJob('*/1 * * * *', async() => {
//expand this function to be responsible for looping the data
for (let symbol of symbols) {
//we can pass symbol to getBTCData instead of making it
//responsible for figuring out which symbol it should get
await getBTCData(symbol);
await sleep(8000);
}
});
//make this a helper function so `saveToDatabase()` isn't also responsible for it
const getDateTime = () => {
let today = new Date();
let date = today.getFullYear() + '-' + (today.getMonth() + 1) + '-' + today.getDate();
let time = today.getHours() + ":" + today.getMinutes() + ":" + today.getSeconds();
return date + ' ' + time;
};
const saveToDatebase = async(symbol, BTCdata) => {
try {
const url = 'mongodb://username:password#ipadress:port/dbname';
let dateTime = getDateTime();
let db = await MongoClient.connect(url, { useUnifiedTopology: true });
const dbo = db.db('Crypto');
const myobj = Object.assign({ Name: symbol, Date: dateTime }, BTCdata[0]);
await dbo.collection(symbol).insertOne(myobj);
const average = await dbo.collection(symbol).aggregate([{
'$match': {
'Date': { '$gte': new Date((new Date().getTime() - (7 * 24 * 60 * 60 * 1000))) }
},
},
{
'$group': {
_id: null,
'Volume': { '$avg': '$Volume' }
},
}
]).toArray();
console.log('1 document inserted');
console.log(average);
db.close();
} catch (e) {
console.error(e)
}
};
EDIT1
If I delete $match part my script is working and I receive average of Volume.
Screenshot of terminal after success try without $match
EDIT2
According to the last answer I understand that I need to change Date format from string to object, but I really can't get how I can do it in this part?
const getDateTime = () => {
let today = new Date();
let date = today.getFullYear() + '-' + (today.getMonth() + 1) + '-' + today.getDate();
let time = today.getHours() + ":" + today.getMinutes() + ":" + today.getSeconds();
return date + ' ' + time;
};
EDIT3
After editing the Date format I receive a Document in MongoDB in strange Date format like - Date:2020-07-20T13:24:02.390+00:00
Code here:
const getDateTime = () => {
let today = new Date();
let date = today.getFullYear() + '-' + (today.getMonth() + 1) + '-' + today.getDate();
let time = today.getHours() + ":" + today.getMinutes() + ":" + today.getSeconds();
return new Date();
};

Answer 1

The problem is on the Date field format.
The getDateTime function returns a string so Mongo is managing the field as a string not as a Date object so the $gte check will compare string not dates.
You should change the function to getDateTime = () => new Date(). Mongo will manage the date correctly storing in UTF Timezone.
Tring to query a date-string in the $match field would be really difficult.
Edit:
To update the typing just:
const getDateTime = () => {
return new Date();
};