[{status:{isError:false},date_posted:ISODate("2020-02-01T10:00:00Z"),continent:"Europe"},{status:{isError:false},date_posted:ISODate("2020-02-01T10:03:00Z"),continent:"Europe"},{status:{isError:false},date_posted:ISODate("2020-02-01T10:02:00Z"),continent:"Asia"},{status:{isError:false},date_posted:ISODate("2020-02-02T10:00:00Z"),continent:"Europe"},{status:{isError:false},date_posted:ISODate("2020-02-02T12:00:00Z"),continent:"Europe"}]

db.collection.aggregate([{$match:{"status.isError":false}},{$group:{_id:{date:{$dateTrunc:{date:"$date_posted",unit:"day"}},continent:"$continent"},count:{$sum:1}}},{$project:{_id:0,continent:"$_id.continent",date:"$_id.date",count:1}},{$setWindowFields:{partitionBy:"$continent",sortBy:{"date":1},output:{cumulativeCount:{$sum:"$count",window:{documents:["unbounded","current"]}}}}}])