DataclassTransform does not serialise on Optional annotation

[tomblazejewski]

dash-core-components 2.0.0
dash-extensions      1.0.18
dash-html-components 2.0.0
dash-table           5.0.0

When modifying the example from this link: https://www.dash-extensions.com/transforms/dataclass_transform as:

from datetime import datetime
from typing import Optional

from dash_extensions.enrich import (
    DashProxy,
    DataclassTransform,
    Input,
    Output,
    State,
    dcc,
    html,
)


@dataclass
class Person:
    name: str
    date_of_birth: datetime


app = DashProxy(transforms=[DataclassTransform()])
app.layout = html.Div(
    [
        dcc.Input(id="name", value="John Doe"),
        dcc.DatePickerSingle(id="picker", date=datetime(1990, 1, 1)),
        dcc.Store(id="store"),
        html.Button("Submit", id="btn"),
        html.Div(id="log"),
    ]
)


@app.callback(
    Input("btn", "n_clicks"),
    State("name", "value"),
    State("picker", "date"),
    Output("store", "data"),
)
def submit(_, name, date):
    dt = datetime.fromisoformat(date)
    return Person(name, dt)  # no (manual) serialization here


@app.callback(
    Output("log", "children"),
    Input("store", "data"),
)
def log(person: Optional[Person]):
    return f"{person.name} was born on {person.date_of_birth}"  # no (manual) deserialization here


if __name__ == "__main__":
    app.run_server(port=8060)

The object returned from the "submit" function is a dict (not serialised).

[tomblazejewski]

I believe I got it to work by changing the _try_load method for DataclassTransform - if this is something desirable I could create a PR