Ask HN: Thought experiment: coding a VanillaJS front end

Hey, I know there are a lot of long-time frontend devs on this forum. As for me, I've worked with Dojo, JQuery, Backbone, React, and most recently, Angular.

A random thought struck me this morning: what would we do on a large project in 2017, if there were no frontend frameworks?

For some reason I can't let this go. So I thought it would be fun to post the concept here and see if anyone wants to join in.

Questions:

* Would you transpile from another language, and if so, what?

* How would you structure your code?

* What capabilities / browsers would you support?

* Would you request JSON or HTML from the server, or both?

* Would you test your code and with what?

* What build tools would you use?

* How would you import and use external libraries and utilities?

* How would you avoid namespace collisions?

* Would you make your app an SPA?

* What are the main challenges / problems you would face?