'Promise' is undefined in system.js

[digitaldonkey]

[guybedford]

In IE11 you must explicitly include a Promise polyfill in SystemJS. See https://github.com/systemjs/systemjs#polyfills-for-older-browsers.

[enure]

In my case, I have bundled a Promise polyfill with s.js and we load that file dynamically if the es6 dynamic import fails.