[{"si":"10.131.6.79","sp":36158,"n":"snat","tsi":"194.230.159.203","tsp":36158,"di":"205.185.208.165","dp":443},{"si":"10.128.103.115","sp":56261,"n":"dnat","tdi":"194.230.159.107","tdp":56261,"di":"8.253.207.243","dp":443}]

db.collection.aggregate([{$facet:{q1:[{$match:{n:"snat"}},{$project:{_id:0,sourceIp:"$si",sourcePort:"$sp",sourceNatIp:"$tsi",sourceNatPort:"$tsp",destIp:"$di",destPort:"$dp",trandisp:"$n"}}],q2:[{$match:{n:"dnat"}},{$project:{_id:0,sourceIp:"$si",sourcePort:"$sp",destinationNatIp:"$tdi",destinationNatPort:"$tdp",destIp:"$di",destPort:"$dp",trandisp:"$n"}}]}},{$project:{all:{$concatArrays:["$q1","$q2"]}}},{$unwind:"$all"},{$replaceRoot:{newRoot:"$all"}}])