Specialized Django `json_script` template tag for more complex data types.

data_tags.py

import dataclasses

from django import template
from django.utils import html
from django.utils.safestring import mark_safe
from rest_framework.renderers import JSONRenderer
from rest_framework.utils import encoders


register = template.Library()


class JSONEncoder(encoders.JSONEncoder):
    def default(self, obj):
        if dataclasses.is_dataclass(obj):
            return dataclasses.asdict(obj)
        return super().default(obj)


@register.filter()
def advanced_json_script(data, element_id):
    """
    Based on: django.utils.html.json_script

    Escape all the HTML/XML special characters with their unicode escapes, so
    value is safe to be output anywhere except for inside a tag attribute. Wrap
    the escaped JSON in a script tag.
    """

    renderer = JSONRenderer()
    renderer.encoder_class = JSONEncoder

    json_str = renderer.render(data).decode("utf-8")
    return html.format_html(
        '<script id="{}" type="application/json">{}</script>',
        element_id,
        mark_safe(json_str),
    )