How to register JavaScript helpers with Handlebars.net

How would we register these two JavaScript helpers in Handlebars.Net?

For Moment.js:

Handlebars.registerHelper("formatDate", function (datetime, format) {
    return moment(datetime).format(format);
});

For a java script calculation:

Handlebars.registerHelper("formatPercent", function (val1, limit) {
    return Math.ceil(100 * val1 / limit);
});m