Converting date objects

[mudassarzahid]

Is there a way to support datetime / date to Date conversions? Currently, they are converted to string.

• Python input:

from datetime import date

class MyModel(BaseModel):
    start_date: date

• TypeScript output:

export interface MyModel {
  start_date: string;  // should be Date
}

[phillipdupuis]

Hi @mudassarzahid, it turns out this actually is possible. I didn't expect that!

All you need to do is add {"tsType": "Date"} to the json_schema_extra for date/datetime fields.

Example:

import datetime
from pydantic import BaseModel, Field

class MyModel(BaseModel):
    a: datetime.date = Field(json_schema_extra={"tsType": "Date"})
    b: datetime.datetime = Field(json_schema_extra={"tsType": "Date"})

yields

export interface MyModel {
  a: Date;
  b: Date;
}

[phillipdupuis]

And if you want to automatically make this change EVERYWHERE in a project, I'd recommend using typing.Annotated like so:

import datetime
from typing import Annotated
from pydantic import BaseModel, Field

Date = Annotated[datetime.date, Field(json_schema_extra={"tsType": "Date"})]
DateTime = Annotated[datetime.datetime, Field(json_schema_extra={"tsType": "Date"})]

class MyModel(BaseModel):
    a: Date
    b: DateTime

Use the annotated Date and DateTime types in place of datetime.date/datetime.datetime and it will all just work.

You could probably also do this by modifying the pydantic schema generator, but those APIs always seem to be in flux so in my eyes it's not worth the effort.

[phillipdupuis]

Does this work as a solution for you?

I don't think I'll make this into a standard thing, since string is technically the correct type (in terms of JSON serialization). But it's good to know that it's possible.

[mudassarzahid]

@phillipdupuis That's perfect, thank you!