V1: Enabling Experimental Features

Tip

Early access to V1 is available starting from v0.33.0! This enables performance optimizations and introduces experimental changes that will be part of the upcoming major v1 release. 🚀

To opt-in to experimental v1 features, users can pass v1 = True in the Meta setting.

Example: Opting In To v1 Features

from dataclasses import dataclass
from dataclass_wizard import JSONPyWizard
from dataclass_wizard.v1 import Alias

@dataclass
class A(JSONPyWizard):
    class _(JSONPyWizard.Meta):
        v1 = True

    my_str: str
    version_info: float = Alias(load='v-info')

a = A.from_dict({'my_str': 'test', 'v-info': '1.0'})
print(a)  #> A(my_str='test', version_info=1.0)

assert a.version_info == 1.0
assert a.to_dict() == {'my_str': 'test', 'version_info': 1.0}

Note

DataclassWizard is now the recommended approach for v1 opt-in, as it (1) applies the @dataclass decorator to subclasses automatically and (2) enables v1=True in the Meta settings.

from dataclass_wizard import DataclassWizard
from dataclass_wizard.v1 import Alias

class A(DataclassWizard):
    my_str: str
    version_info: float = Alias(load='v-info')

Without Inheritance

For simple dataclasses that do not subclass DataclassWizard or JSONPyWizard, you can use LoadMeta (and similar) utilities:

from dataclasses import dataclass
from dataclass_wizard import DumpMeta, LoadMeta, asdict, fromdict
from dataclass_wizard.v1 import Alias

@dataclass
class A:
    my_str: str
    version_info: float = Alias(load='v-info')

LoadMeta(v1=True).bind_to(A)
DumpMeta(key_transform='NONE').bind_to(A)

a = fromdict(A, {'my_str': 'test', 'v-info': '1.0'})
print(a)  #> A(my_str='test', version_info=1.0)

assert a.version_info == 1.0
assert asdict(a) == {'my_str': 'test', 'version_info': 1.0}

Pass case on Sub-class

This is a lesser-known (but equally valid) approach to opting in to experimental v1 features and worth documenting.

When sub-classing from JSONWizard (or a subclass thereof), pass in case (alternatively, load_case and dump_case for de/serialization respectively) which determines the letter case for JSON keys in de-serialization. Read more about Key Case Transformation.

For example, set the AUTO key casing mode:

from dataclass_wizard import DataclassWizard
from dataclass_wizard.class_helper import get_meta
from dataclass_wizard.v1 import Alias


class A(DataclassWizard, case='AUTO'):
    my_str: str
    version_info: float = Alias(load='v-info')


# Confirm `v1` is automatically enabled
assert get_meta(A).v1  # > True

a = A.from_dict({'My-Str': 'test', 'v-info': '1.0'})
print(a)  #> A(my_str='test', version_info=1.0)

assert a.version_info == 1.0
assert a.to_dict() == {'my_str': 'test', 'version_info': 1.0}

Discovering New Settings

All new settings related to v1 opt-in are prefixed with v1_ for convenience and discoverability. For example:

v1_unsafe_parse_dataclass_in_union = False

Note: The v1_unsafe_parse_dataclass_in_union setting is documented separately. Refer to the Enhanced Union or | Type Parsing page for details.

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Important Notes on Experimental Features

Warning

Experimental Nature: The v1 features are experimental and may change in future releases. Exercise caution when using these features in production environments.

Backward Compatibility: Enabling v1 introduces new features and optimizations that may come with breaking changes. However, the core functionality should remain the same.

For more details, refer to the Dataclass Wizard Documentation.