How i can convert string (_id) to BSON object?
As a driver I'm using monk.
Monk defines the id and oid (alias) methods for casting to ObjectID:
users.id() // returns new generated ObjectID
users.id('hexstring') // returns ObjectId
users.id(obj) // returns ObjectId
Though it seems capable of working with the string as well:
users.findById('hex representation', function(err, doc){});
users.findById(oid, function(err, doc){});
convert to json then to bson I think