[{"name":"First","value":8},{"name":"Second","value":2},{"name":"Third","value":5}]

db.collection.aggregate([{$sort:{value:1}},{$group:{_id:1,items:{$push:{name:"$name",value:"$value"}}}},{$unwind:{path:"$items",includeArrayIndex:"index"}},{$project:{_id:0,name:"$items.name",value:"$items.value",index:{$add:["$index",1]}}}])