gistfile1.js

var assert = require('assert');

var helpers = {
  view: function() {
    return "viewing: " + this.msg;
  }
}
// jade
// "h1= view()"
// compiled jade
var templates = {
  home: function(locals) {
    var view = locals.view;
    return "<h1>" + view() + "</h1>";
  }
}

function templateFinder(templateName) {
  var template = templates[templateName];
  return function extendedTemplate(locals) {
    for(fn in helpers) {
      locals[fn] = helpers[fn].bind(locals);
    }
    return template.call(locals, locals);
  }
}
var locals = { msg: 'hello world' };

var html = templateFinder("home")(locals);

console.log(html);
// => <h1>viewing: hello world</h1>