Ask HN: Should JavaScript newcomers bypass ES5?

Hi,

I'm a CS teacher and the author of two entry-level JavaScript courses written in ES5. I'm considering the creation of a book that would include the material in these courses. A more advanced chapter would cover (among other things) higher-order functions, modules and of course ES2015. This book would target JS newcomers, not experienced folks.

I'm tempted to revamp my courses and start directly with the ES2015 syntax instead of ES5, but I see drawbacks to this approach, mainly the need for a transpiler and the sheer volume of existing ES5 code my readers won't be familiar with.

So my question is: how one should learn JavaScript in 2016, with ES5 first and ES2015 after a while, or directly with ES2015?

Thanks in advance for your feedback.