check in the collection,what id has no records in mongodb -

i have few ids in array

  var editions= ["aaa","bbb","ccc","ddd",......,"zzz"] 

i have collection called participants

it has record called edition

edition:"aaa" 

now want ids in editions array has no records in participants collection

if want of happen on server can use aggregation framework , set features available, notably $setdifference operator mongodb 2.6 , greater:

db.collection.aggregate([     { "$group": {         "_id": null,         "editionsfound": { "$addtoset": "$edition" }      }},     { "$project": {        "notfound": {            "$setdifference": [                editions,                "$editionsfound"            ]        }     }} ]) 

or can on client performing difference between result , original via .distinct() method:

array.prototype.diff = function(a) {     return this.filter(function(i) {return a.indexof(i) < 0;}); };  var result = db.collection.distinct("edition");  editions.diff(result); 

or similar approach in language of choice.

either way means getting distinct values , comparing source list find difference.