mongodb - How do I formulate find() based on multiple _ids? -

i trying retrieve 2 objects based on 2 object _ids.

as demonstrated in code below, session.get(); function retrieves 2 _id, use in query.

 var selectedid = session.get('selecteditemidset');  selectedid = selectedid.tostring();  selectedid = selectedid.split(",");    alert(selectedid);  

the alert above pops out 2 _ids : lzjka8s3wynwhakze, ikrbcdutthrwkecuv

 console.log("selectedid is: ",...selectedid);  

the above console() function yeilds:

selectedid is: lzjka8s3wynwhakze ikrbcdutthrwkecuv

 buylist.find({_id:{ "$in": selectedid} }).fetch(); 

the query above returns 1 object, namely object _id: "lzjka8s3wynwhakze" , not 2 objects expected results.

just clarify, expected result should 2 objects _ids: lzjka8s3wynwhakze, ikrbcdutthrwkecuv

kindly point out doing wrong here?