javascript - MongoDB $elemMatch not working for subdocument -

im trying specific quiz in database id:

static getquiz(db, id, cb){ //db database connection, id quiz id, cb callback         db.find({ _id : "8ra4rey50eqkflwk"}, {"quiz" : { $elemmatch : { _id : id}}}, function(err, doc){             if(cb){                 cb(err,doc);                 console.log(doc); //only return _id : "8ra4rey50eqkflwk"             }         })     } 

json database:

{    "_id":"8ra4rey50eqkflwk",    "quiz":[       {          "_id":"1b944055-2b15-4838-7e7a-beef4c9a5a62",          "title":"test",          "description":""       },       {          "_id":"7dc53529-206c-6003-1d3c-133264d7ad81",          "title":"aaaa",          "description":""       },       {          "_id":"db3c788f-56b3-f9c8-8a25-affb2981e12f",          "title":"lala",          "description":""       },       {          "_id":"20388c1f-1a00-4f7b-3d25-9db56247a6bf",          "title":"asdasd",          "description":""       }    ] } 

above code not working, tested with:

db.find({ _id : "8ra4rey50eqkflwk"}, {"quiz" : { $elemmatch : { title : "test"}}}) 

but result still root id => _id : "8ra4rey50eqkflwk".

i expects result when search quiz id "1b944055-2b15-4838-7e7a-beef4c9a5a62" should be:

{    "_id":"8ra4rey50eqkflwk",    "quiz":[       {          "_id":"1b944055-2b15-4838-7e7a-beef4c9a5a62",          "title":"test",          "description":""       },     ] } 

any solutions? im using nedb https://github.com/louischatriot/nedb same syntax mongodb. thanks

edit: tried code using mongodb console, works beautifully! maybe thats nedb bug?

        db.a.find(                {_id : "8ra4rey50eqkflwk"},           {               "quiz" : {                    $elemmatch : { "title" : "test"}                      }           }); 

miss spelled title _title