Callback on loaded via requirejs


I’m trying to import braintree via require with a callback function once it’s loaded but it seems like the require syntax doesn’t work as expected in meteor. any ideas what I am doing wrong or how to fix this?

const braintree = require(
  function() {
    console.log('braintree loaded');

Bonus question:
Is it possible to require external scripts like from a CDN. Also doesn’t seem to work for some reason.