Django-jsconstants is an interface for communicating constants between Python code and frontend Javascript. This allows you to avoid hardcoding constants into your Javascript, as that is prone to breaking silently and unpredictably when the underlying codebase changes. Jsconstants is robust and fail-fast: changing a constant's value won't affect behavior, while changing a constant's name (or removing it) will throw a detectable Javascript error.
Before you can import constants into a template, they must first be registered into the jsconstants module.
Example: myapp/models.py
from django_jsconstants import jsconstants
COLOR_RED = "FF250D"
COLOR_MAGENTA = "FF00A9"
SOME_CONSTANT = "not_needed"
jsconstants.register(__name__, "COLOR_RED", "COLOR_MAGENTA")
class MyAppModel...
The first argument to the register... methods is the path to the module being registered. There are several variations of
the register method:
register_all(module)- finds and registers all variables in ALL_CAPS. Careful! These constants will be publicly visible in the template, so take care to not register sensitive constants like private keys.register_all_except(module, *exceptions)- finds and registers all variables in ALL_CAPS, except those specified.register(module, *constants)- only register the constants specified.
In your template, simply use the jsconstants template tag and pass it a list of modules that you'd like to import.
Example file:yourproject/templates/yourproject/base.html
{% load jsconstants %}
<html>
<head>
{% jsconstants "myapp.models" "utilsapp.tools" %}
</head>
<body>
</body>
</html>
From inside of any Javascript function or file on the page, you can access the global jsconstants object to retrieve
registered constants.
var COLOR_CHOICE_RED = jsconstants.get('myapp.models', 'COLOR_RED');