i18n-abide is a translation library for node.js apps.
i18n-abide and swig need to be added as a middleware to the express (or other framework) app.
Also, format and gettext need to be supplied in the context of swig (using res.locals).
// setup the trans & blocktrans template helpers
require('swig-i18n-abide')(swig);// single line translations
{% trans "I'll be translated" %}
// single line translations with replacements
{% trans "String %(foobar)s with string replacements" %}
// multiline translations with replacements and maybe html
{% blocktrans with name=name url=url %}
Hello <a href="%(url)s">%(name)s</a>.
Pleasure to meet you.
{% blocktrans %}