MongoError: The $cond accumulator is a unary operator

Question

Consider this pipeline.

let Pipeline = [
    { $match: {
    }},
    { $group: {
        workHours: { $sum: { $divide: [ { $subtract: ['$workTime.end', '$workTime.start'] } , { $multiply: [3600, 1000] }] }},
        breakHours: { $sum: { $divide: [ { $subtract: ['$breakTime.end', '$breakTime.start'] } , { $multiply: [3600, 1000] }] }},
        weekEndHours: {
            $cond: [
                { $or : [ { $eq : [{ $dayOfWeek : '$workTime.start' }, 1 ] }, {$eq : [{ $dayOfWeek : '$workTime.start' }, 7 ] }] },
                { $sum: { $divide: [ { $subtract: ['$workTime.end', '$workTime.start'] } , { $multiply: [3600, 1000] }] }},
                0
            ]
        }
    }},
];

I'm trying to get sum of work hours, break hours and weekend hours. Work hours and break hours works fine. Now I want to use condition inside weekend hours which is if the day of the date is either 1 or 7 only then count the total hours in the key.

Then it is showing me the error 'The $cond accumulator is a unary operator'. I don't know what is wrong with my group query.

Answer 1

Got Solution and also extended pipeline conditions.

let Pipeline = [
    { $match: {
    }},
    { $group: {
        _id: '$memberId',
        workHours: { $sum: { $divide: [ { $subtract: ['$workTime.end', '$workTime.start'] } , { $multiply: [3600, 1000] }] }},
        breakHours: { $sum: { $divide: [ { $subtract: ['$breakTime.end', '$breakTime.start'] } , { $multiply: [3600, 1000] }] }},
        weekEndHours: {
            $sum: {
                $cond: [
                    { $or : [ { $eq : [{ $dayOfWeek : { date: '$workTime.start', timezone: timezoneOffset}}, 1 ] }, {$eq : [{ $dayOfWeek : { date: '$workTime.start', timezone: timezoneOffset}}, 7 ] }] },
                    { $divide: [ { $subtract: ['$workTime.end', '$workTime.start'] } , { $multiply: [3600, 1000] }] },
                    0
                ]
            }
        },
        weekDayHours: {
            $sum: {
                $cond: [
                    { $or : [
                            { $eq : [{ $dayOfWeek : { date: '$workTime.start', timezone: timezoneOffset}}, 2 ] },
                            { $eq : [{ $dayOfWeek : { date: '$workTime.start', timezone: timezoneOffset}}, 3 ] },
                            { $eq : [{ $dayOfWeek : { date: '$workTime.start', timezone: timezoneOffset}}, 4 ] },
                            { $eq : [{ $dayOfWeek : { date: '$workTime.start', timezone: timezoneOffset}}, 5 ] },
                            { $eq : [{ $dayOfWeek : { date: '$workTime.start', timezone: timezoneOffset}}, 6 ] }
                        ]
                    },
                    { $divide: [ { $subtract: ['$workTime.end', '$workTime.start'] } , { $multiply: [3600, 1000] }] },
                    0
                ]
            }
        },
    }},
    { $addFields:{
        totalWorkedHours: { $subtract: [ '$workHours', '$breakHours'] }
    }}
];