How to run/build JavaScript code in Sublime

Confession: I setup a Node build system in Sublime before I even know what Node was. As soon as I installed Sublime, I wondered, "Why can't I run anything in JavaScript in here?" 

So I googled and figured it out. Of course, I promptly forgot how I did it (people at Hack Reactor have asked, and I just stare at them blankly). 

Luckily, Eliot Winder has documented this process for us! Check it out.

CMD-B, y'all. It's a game changer.