When I started out, this and "Secrets of the JavaScript Ninja" didn't help me understand. For me, after months of trying to understand JavaScript, Dmitry Soshnikov's post, JavaScript. The Core, made understanding closure, prototype, and scope chain crystal clear in about 30 minutes. [0] Also, every time someone shares a basics on JavaScript link on Hacker News I also share my interview guide which despite its popularity has yet to land me a job writing JavaScript. Nonetheless, I love writing JavaScript and understanding it and some of the APIs like Angular, Lodash, Nightmare, and async makes me feel empowered. It doesn't cover any topics in ES6 yet.[1]

[0] http://dmitrysoshnikov.com/ecmascript/javascript-the-core/

[1] https://github.com/adam-s/js-interview-review