Comment by fiatjaf

I really don't understand this kind of courses.

    What Will I Learn?

    ES6 Easy Wins - New Variables, Scoping and Template Strings
    New Language Features — Arrow Functions, Destructuring
    New Iterables and Looping over data
    What the heck those ...three ...little ...dots actually do
    How to structure your JavaScript with Modules and NPM
    Advanced Classes, Proxies, Generators, Sets and Maps
    How to write clean and consistent JavaScript with ESLint
    Proper tooling + bundling setup with Webpack

$60 for things you can learn by reading a free blog post and actually trying it yourself in a side-project?

Unless you've never did any Javascript in your life, in which case you can still learn JS basics in a free tutorial, better than a "learn ES6 best-practices" course.