[{lastVisitedResources:[1,2,3,4,5,6,7,8,9,10]}]

db.collection.update({},[{$set:{lastVisitedResources:{$slice:[{$concatArrays:[[3],{$filter:{input:{$ifNull:["$lastVisitedResources",[]]},cond:{$ne:["$$this",3]}}}]},50]}}}],{"multi":false,"upsert":false})