deliveryStatisticsAggregations.js

// Group by minute:
var format = '%Y-%m-%dT%H:%M';

// The string field for the record's period
var periodField = 'period';
// The field that is used as the average weight
var weightField = 'generated';
// The filter field to be multiplied in the average: $avgSolveTime, $callbacksExecuted, etc
var valueField = 'callbacksExecuted';
// The date field used to group data by minute
var dateField = 'last';


// For a single user
var aggregationOneUser = db.getCollection('statsSerpsAggregatedMinute').aggregate([
    {
        $match: {
            period: { '$gte': '2019-01-01T00:00:00.000Z', '$lte': '2019-02-01T00:00:00.000Z' },
            userId: 'VGWBkUCcXAql5bTtP'
        }
    },
    {
        $group: {
            _id: { $dateToString: { format: format, date: "$last" } },
            numerator: { $sum: { $multiply: [ '$'+[weightField], '$'+[valueField] ] } },
            denominator: { $sum: '$'+[weightField] }
        }
    },
    {
        $project: {
            weighedAverage: { $divide: [ "$numerator", "$denominator" ] },
        }
    },
    {
        $sort: {_id: 1}
    }
]);

aggregationOneUser.forEach(function(item) {
   print('* Aggregation: ' + JSON.stringify(item));
});

// For all users
var aggregationAllUsers = db.getCollection('statsSerpsAggregatedMinute').aggregate([
    {
        $match: {
            [periodField]: { '$gte': '2019-01-01T00:00:00.000Z', '$lte': '2019-02-01T00:00:00.000Z' },
        }
    },
    {
        $group: {
            _id : { $dateToString: { format: format, date: '$'+[dateField] } }, // group by minute
            numerator: { $sum: { $multiply: [ '$'+[weightField],  '$'+[valueField] ] } },
            denominator: { $sum: '$'+[weightField] }
        }
    },
    {
        $project: {
            weighedAverage: { $divide: [ "$numerator", "$denominator" ] },
        }
    },
    {
        $sort: {_id: 1}
    }
]);

aggregationAllUsers.forEach(function(item) {
   print('* Aggregation: ' + JSON.stringify(item));
});