I don't believe the DataCollection APIs actually return Map (e.g, metadata.compression instanceof Map !== true). It would be surprising as an end user to get either an object or a Map.
The current types:
This was probably intended to be:
Additionally, these types could be augmented to include some of the common props: One small example:
It depends on the encoding setting specified by the user: https://docs.datastax.com/en/developer/nodejs-driver/4.2/features/datatypes/collections/#ecma-script-map-and-set-support
In any case, it’s a good idea to use [option: string]: any.