For anyone interested in trying some of this stuff out (which I highly recommend, because a lot of the new stuff in ES6 is really great), Google has an awesome tool called Traceur [https://github.com/google/traceur-compiler] that will compile ES6 into ES5.

There's also an online version here: [https://github.com/google/traceur-compiler] that's great for quick little experiments. And, as an added bonus, it encodes your script in the URL so you can share it.