[{"token":"c1","class":"bscs",courses:["ITM","CS54","KHE"]}]

db.collection.aggregate([{$unwind:{path:"$courses",includeArrayIndex:"index"}},{$project:{token:{$cond:[{$eq:["$index",0]},"$token",""]},class:{$cond:[{$eq:["$index",0]},"$token",""]},courses:1}}])