ES6 makes it easy to define classes, but you can't have decorated functions. For that, you'll still need to drop to using prototype.
Same with non-method attributes.
You have just read ES6 class pitfalls, written on February 25, 2015. This is Today I Learned, a collection of random tidbits I've learned through my day-to-day web development work. I'm Rico Sta. Cruz, @rstacruz on GitHub (and Twitter!).