This is a pure JS (front to back) of perl's Template Toolkit:

  http://template-toolkit.org/

Yes, I'm aware of the Jemplate module, but that uses perl to produce a .js file
which isn't of much use for a project like flusspferd (a JS shell+common
modules):

  http://github.com/ruediger/flusspferd/tree/master

Play around with a live demo at

  http://perlitist.com/static/tt/