When trying to create index with next code

db.collection( COLLECTION_NAME ).createIndex(
    { 'key.external_id': 1, 'key.type': 1 },
    { unique: true, sparse: true, name: INDEX_NAME},
    next
  )

I've got next error

{ [MongoError: key key.external_id must not contain '.']
  name: 'MongoError',
  message: 'key key.external_id must not contain \'.\'' }

This error is produced by bson library (e.g. bson.checkKey). By deeper research:

• This behavior is controlled by checkKey option, that passed to bson.
• The checkKey option is set to false (which is OK) in node-mongodb-native.
• But it is always set to true and passed options are ignored here in mongodb-core.

Please suggest a solution on this issue.