Learn ECMAScript6 by doing it
es6katas.org
es6katas.org
Edit: The Unicode in strings one teaches you both the \uXXXX and \u{xxxxxx} syntaxes, yet the former isn't new.
Does anyone know if you can use ES6 code side by side with ES5 without any issues?
Compiling JavaScript is one solution to the problem that you have no control over the client interpreter and the 'version' of your code that it supports. It isn't an ideal solution, but it means we can move the language forward without worrying about breaking everything.
I'm not. Looking at this for a few minutes will impact my vision and it will most likely also cause severe headaches. Migraine is fun like that.
Anyhow, the tddbin site uses a black on white color scheme. There is no reason for the index site to be inverted.
Presuming your OS has such features, you might find it helpful to invert the screen when looking at pages with light text/dark background.
(I change my screen to normal for such sites.)
HTH
I have a small bookmarklet for nuking colors, which I can run via some shortcut (ShortcutKey2URL).
javascript:for(var e of document.querySelectorAll('*')){e.style.color=window.getDefaultComputedStyle(e).color;e.style.backgroundColor='#fff'}void(0)
Kinda crude but it works well enough.