How to use helpers in a client-side Jade template using Backbone.js?

I'd like to use momentjs (more generally, any other function) as helper in a Jade template, both for the server and the client. On the server (Express.js 3.x), I'm adding it to app.locals, and it works fine:

Server-side

// Locals
app.locals.moment = require('moment');

// Routes
app.get('/', function (req, res) {
    res.render('index.jade')
});

app.listen(config.get('server').port);

So using the moment helper works fine when the template (index.jade) is rendered by the server and then served at / as plain HTML.

Client-side

On the client (RequireJS modules system) I'm using Backbone.js along with, again, Jade in order to render views. How can I use moment helper in navbar.jade?

define(
    ['jade', 'backbone', 'text!views/navbar.jade'],
    function (Jade, Backbone, navbarTemplate) {
        return Backbone.View.extend({

            initialize: function () {
                this.template = Jade.compile(navbarTemplate);
            },

            render: function () {
               this.$el.html(this.template(this.model));

               return this;
            }

        });
    }
);

EDIT: based on Peter Lyons suggestion, I've wrapped compile function. moment works but foo doesn't (p= moment() vs p= foo(), the latter gives me cannot call function of undefined):

define(['jade', 'lodash', 'moment'], function (Jade, _) {

    return {
        compile: function(str, options) {

            options.locals = _.extend({
                moment:  require('moment'),
                foo: function () { return 'bar'; }
            }, options.locals);

            return Jade.compile(str, options);
        }
    };
});

When you invoke the compiled template function in the browser, there's no out of the box app.locals, so you would have to code it.

//customJade.js module
define(function (require, exports) {
    var jade = require('jade');
    var moment = require('moment');
    exports.compile = function(jadeString) {
      //build the normal jade template function
      var jadeFn = jade.compile(jadeString);
      //build a wrapper function with same API
      var customFn = function(locals) {
        //in the wrapper, add your shared locals as needed
        locals.moment = locals.moment || moment;
        locals.appName = "Super Happy Fun App!";
        //return the result of the real jade template function,
        //but with combined locals
        return jadeFn(locals);
      };
      //return your wrapper function instead of the regular jade function
      return customFn;
    }
});

.

//your backbone view module
define(['customJade', 'jadeTemplateString'], function (customJade, jadeTemplateString) {
   //blah blah your View subclass...
   template: customJade.compile(jadeTemplateString),
   //...
});