Raising this ticket specifically for the error raised when an invalid compressor is supplied, however it may be beneficial to align all connection parsing errors in a similar fashion.

For example, in the 3.6 Driver the error is:

throw new MongoParseError(
        'Value for `compressors` must be at least one of: `snappy`, `zlib`'
      );

whereas in the 4.0 Driver the error is:

throw new MongoParseError(`${c} is not a valid compression mechanism`);

Ideally these errors would consistently include both:

• the invalid value that was passed
• the list of accepted values (where appropriate)