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db.collection.aggregate([{$project:{outVal:{$cond:{if:{$eq:["$win",true]},then:"1",else:"0"}}}},{$group:{_id:null,allRuns:{$push:"$outVal"}}},{$project:{totalString:{$reduce:{input:"$allRuns",initialValue:"",in:{$concat:["$$value","$$this"]}}}}},{$project:{splitItems:{$split:["$totalString","0"]}}},{$unwind:"$splitItems"},{$project:{length:{$strLenCP:"$splitItems"}}},{$sort:{length:-1}},{$limit:1}])