Metaprogramming in ES6: Symbols and why they're awesome

You've heard of ES6 right? It's the new version of JavaScript that is awesome in so many ways. I frequently wax lyrical about all of the amazing new features I keep discovering with ES6, much to the chagrin of my colleagues (consuming someone's lunch break talking about ES6 Modules seems to be not to everyone's liking). A set of great new features for ES6 comes in the form of a slew of new metaprogramming tools, which provide low level hooks into code mechanics. Not much has been written on them, so I thought I'd do a teensy weensy 3 part post on them (sidebar; because I'm so lazy and this post has been sat in my drafts folder - 90% done - for three months, a bit more has been written about them since I said that):