Echo JS 0.11.0

Why would do you say that ES6 by adding Class definition will "fix THIS crap"? 

You will still need to understand how "this" binding gets resolved depending on the execution context. 

Here is the spec one should use as a first-hand source of information. Its not easy to learn from there but it could give one a sense of real understanding of the keyword "this":

https://people.mozilla.org/~jorendorff/es6-draft.html#sec-this-keyword