Make the Python json encoder support Python’s new dataclasses

Much like you can add support to the JSON encoder for datetime objects or Decimals, you can also provide a custom encoder subclass to serialize dataclasses:

import dataclasses, json

class EnhancedJSONEncoder(json.JSONEncoder):
        def default(self, o):
            if dataclasses.is_dataclass(o):
                return dataclasses.asdict(o)
            return super().default(o)

json.dumps(foo, cls=EnhancedJSONEncoder)