django-js-asset -- JS, CSS and JSON support for django.forms.Media

Note! Django 5.2 adds its own support for JavaScript objects. This library has a slightly different API and also supports much older versions of Django, and it also supports CSS and JSON tags.

Usage

Use this to insert a script tag via forms.Media containing additional attributes (such as id and data-* for CSP-compatible data injection.):

from js_asset import JS

forms.Media(js=[
    JS("asset.js", {
        "id": "asset-script",
        "data-answer": "42",
    }),
])

The rendered media tag (via {{ media.js }} or {{ media }} will now contain a script tag as follows, without line breaks:

<script type="text/javascript" src="/static/asset.js"
    data-answer="42" id="asset-script"></script>

The attributes are automatically escaped. The data attributes may now be accessed inside asset.js:

var answer = document.querySelector("#asset-script").dataset.answer;

Also, because the implementation of static differs between supported Django versions (older do not take the presence of django.contrib.staticfiles in INSTALLED_APPS into account), a js_asset.static function is provided which does the right thing automatically.

CSS and JSON support

Since 3.0 django-js-asset also ships a CSS and JSON media object which can be used to ship stylesheets, inline styles and JSON blobs to the frontend. It's recommended to pass those through forms.Media(js=[]) as well since js is a simple list while css uses a dictionary keyed with the media to use for the stylesheet.

So, you can add everything at once:

from js_asset import CSS, JS, JSON

forms.Media(js=[
    JSON({"configuration": 42}, id="widget-configuration"),
    CSS("widget/style.css"),
    CSS("p{color:red;}", inline=True),
    JS("widget/script.js", {"type": "module"}),
])

This produces:

<script id="widget-configuration" type="application/json">{"configuration": 42}</script>
<link href="/static/widget/style.css" media="all" rel="stylesheet">
<style media="all">p{color:red;}</style>
<script src="/static/widget/script.js" type="module"></script>

Compatibility

At the time of writing this app is compatible with Django 4.2 and better (up to and including the Django main branch), but have a look at the tox configuration for definitive answers.