How can I send JSON.stringify(array) data within form-data and decode the JSON with my Django api?

I'm trying to add the functionality to upload an array of date-strings within a form

originally we sent the post data using JSON and sending arrays of data worked, however, when we switched to using form-data in order to make uploading an image easier we started having problems with array types.

since form data has to be sent using a string type I converted the date-string array using JSON.stringify()

const myForm = new FormData();
myForm.set("date_strings", JSON.stringify(dateStrings));

when I post myForm to my Django + DRF API it responds with

{
    "date_strings": [
        "Datetime has wrong format. Use one of these formats instead: YYYY-MM-DDThh:mm[:ss[.uuuuuu]][+HH:MM|-HH:MM|Z]."
    ],
    "status_code": 400
}

In Postman I verified that sending a single date-string works, but when I send a string-array I get the same error.

I believe my Django API tests if the request.data is valid, sees that date_strings are a JSON string, then responds with a 400 Error.

        def create(self, request, *args, **kwargs):
            serializer = self.get_serializer(data=request.data)
            serializer.is_valid(raise_exception=True)

Attempted Solutions:

1. converting the JSON string to an array in the PostViewset create method
   • I can't change request.data['publish_dates'] because it is not mutable and I've seen some advice that you should not attempt to copy or change request data in the viewset because it isn't safe.

2. convert the JSON string to an array in the serializer

   • neither MySerializer's create nor validate methods run (I logged to test).

   • date_strings are formated and created as a separate PublishDate model in the create method,

     class MySerializer(MyChildSerializer):
         date_strings = serializers.ListField(child=serializers.DateTimeField(), min_length=1, max_length=100, write_only=True)
     

How can I send/accept form-data to my Django + DRF API when one attribute is an array of date-time strings?