MongoDB+NodeJs script, that take string date convert it to ISO date, then extract ISO week number then count total per weekNo then calc average, then convert weeknumber to date range for readability

mongodb-groupby-week-unwind-array-withoutFieldNames

```javascript

var mongoose = require('mongoose');

//Set up default mongoose connection
 async function calcSumByWeek() {


     const weeklypipeline = [

         {
             $project: {
                 _id: 1,
                 resultList: 1
             }
         },
         {
             $unwind: '$resultList'
         },
         {
             $project:
                 {
                     pk: {$arrayElemAt: ["$resultList", 0]},
                     created_at: {$arrayElemAt: ["$resultList", 1]}
                 }
         },
         {
             "$addFields": {
                 "created_at": {
                     "$toDate": "$created_at"
                 }
             }
         },
         {$project: {pk: 1, creationWeek: {$week: "$created_at"}}},
         {"$group": {_id: "$creationWeek", count: {$sum: 1}}},
         {$sort: {_id: 1}}
     ];
      // create custom connection
     const Conn = mongoose.createConnection();

// connect to database
     await Conn.openUri('mongodb://127.0.0.1:27017/test2');

// @type {AggregationCursor}
     const addresses = Conn.collection('sam2').aggregate(weeklypipeline);

    const newAddress =  await addresses.toArray();
    const v2 = newAddress.map((a)=>{
         const newAdd = {};
         newAdd.isoWeekNo = a._id;
         newAdd.total =a.count;
        newAdd.dateRange = getDateRangeOfWeek(a._id);
        return newAdd;
     })
     console.log(   v2);
 }
async function averge() {

    const pipelineaverge = [

        {
            $project: {
                _id: 1,
                resultList: 1
            }
        },
        {
            $unwind: '$resultList'
        },
        {
            $project:
                {
                    pk: {$arrayElemAt: ["$resultList", 0]},
                    created_at: {$arrayElemAt: ["$resultList", 1]}
                }
        },
        {
            "$addFields": {
                "created_at": {
                    "$toDate": "$created_at"
                }
            }
        },
        {$project: {pk: 1, creationWeek: {$week: "$created_at"}}},
        {"$group": {_id: "$creationWeek", countTotalPerWeek: {$sum: 1}}},
        {"$group": {_id: null,  theAverage: { $avg: "$countTotalPerWeek" }}},


    ];
    // create custom connection
    const Conn = mongoose.createConnection();

// connect to database
    await Conn.openUri('mongodb://127.0.0.1:27017/test2');

// @type {AggregationCursor}
    const addresses = Conn.collection('sam2').aggregate(pipelineaverge);

    console.log( await addresses.toArray() );
}

Date.prototype.getWeek = function () {
    var target  = new Date(this.valueOf());
    var dayNr   = (this.getDay() + 6) % 7;
    target.setDate(target.getDate() - dayNr + 3);
    var firstThursday = target.valueOf();
    target.setMonth(0, 1);
    if (target.getDay() != 4) {
        target.setMonth(0, 1 + ((4 - target.getDay()) + 7) % 7);
    }
    return 1 + Math.ceil((firstThursday - target) / 604800000);
}

function getDateRangeOfWeek(weekNo){
    var d1 = new Date();
    numOfdaysPastSinceLastMonday = eval(d1.getDay()- 1);
    d1.setDate(d1.getDate() - numOfdaysPastSinceLastMonday);
    var weekNoToday = d1.getWeek();
    var weeksInTheFuture = eval( weekNo - weekNoToday );
    d1.setDate(d1.getDate() + eval( 7 * weeksInTheFuture ));
    var rangeIsFrom = eval(d1.getMonth()+1) +"/" + d1.getDate() + "/" + d1.getFullYear();
    d1.setDate(d1.getDate() + 6);
    var rangeIsTo = eval(d1.getMonth()+1) +"/" + d1.getDate() + "/" + d1.getFullYear() ;
    return rangeIsFrom + " to "+rangeIsTo;
};


calcSumByWeek().then(r => console.log("") );
averge().then(r => console.log("") );
```

sample data

{
	"query": "ssssssssss",
"executionTime ":2319,
"resultCount ":0,
"exception ":null,
"resultList": [
	["9469999954894634", "2022-09-21T12:21:18.360"],
	["9469999955418922", "2022-09-21T12:06:27.927"],
	["9469999955451690", "2022-09-21T12:20:24.737"],
	["9469999955910442", "2022-09-21T18:47:42.022"],
	["9469999955975978", "2022-09-21T15:33:46.790"],
	["9469999956107050", "2022-09-21T13:38:05.998"],
 
	["9471055527978", "2022-09-28T10:54:31.371"]
], "headers": ["xxx", "yyy"], "zzz": false]"
}