Performance issue with multiple range filters (same resources : scripts + styles loaded multiple times)

[daweedm]

The DOM loading of list_filters is slowed down only when one ore more date range filters are used.

I think this is related to the scripts <script src=...> (and styles) that are defined in the following template :

https://github.com/silentsokolov/django-admin-rangefilter/blob/ceb7ed7c750f496f400816760f465f76ad3017cd/rangefilter/templates/rangefilter/date_filter.html#L71-L146

This template is loaded for every "instance" of date filter and make the browser download the same scripts & css multiple times, which slows down the DOM rendering (mostly because of the repetition of scripts inside the HTML document).

A solution for this would be to define a Mixin for the Admin class which defines the needed resources only once using the Media subclass :

class RangeFilterMixin(admin.ModelAdmin):
    class Media:
        css = {
            'all': [
                'path/to/some.css'
            ]
        }

        js = [
            'path/to/some.js'
        ]

I can make a PR, but this will introduce breaking changes, since the inline scripts & resources will be removed from the date_filter.html template and the Mixin will be required to make the filter work.

What do you think about it ? Maybe you have another solution for this ?

[silentsokolov]

A solution for this would be to define a Mixin for the Admin class which defines the needed resources only once using the Media subclass.

I think you could try improve OnceCallMedia

Mixin will be required to make the filter work

I don't think that is a good idea