django javascript translation

Javacript gettext strings does not appear in po files.

implementation:
.html
<script src="{% url 'javascript-catalog' %}"></script>
document.write(gettext('this is to be translated'));
.urls
path('jsi18n/', JavaScriptCatalog.as_view(), name='javascript-catalog'),

terminal:
$ py manage.py makemessages -d djangojs -l es