How to map array of json data in node js

am using mapfunction in my code i would like to pring Qdata of below array but here it says undefined may be it is inside the array of json if am wrong please help me to correct this! my array structure is like this

[ { _id: 201,
    user_id: 141,
    PAN: 1,
    Qdata: 023444 } ]

here is the map fun:

var data = array.map(function(p){
return p.Qdata
} 

via Schüler