I've one question, how do you handle Polyfills?
I really liked the idea from David Gilbertson in the section "Only send polyfills to browsers that need them" from this post:
I've faced a few problems with it, like, the loading time to check the Polyfills is greater than just provide in the code, e.g. "core-js/es6/array.find".
Anyway, thanks for sharing your experience! :)