Aggregate returns Bson Type

I am using the below aggregate query

 var pipeline=[ { $match: { Active:1, Duration:'monthly' } },{ $sample: { size: 3 } }]
   Products.aggregate(pipeline).toArray((err, result) => {
        subscription.added('random-aggregate', 'random-order', {result:result});

it returns the correct result but the ObjectId is in BSON type which makes it difficult to further process it. How can I get the correct Object id of the collection record?bsontype