I'm not 100% sure who's the target audience of this book, frankly. I had the opportunity to read it some time ago and, for someone new to the language/programming, it is clearly difficult to learn from after the first few chapters.
Yeah, I moderate on a forum aimed at beginner programmers undertaking a curriculum that uses JS, and they tend to find the book hard going if they attempt to work through it. I had a look at it when I was already very familiar with the language, and it definitely wasn't aimed at me. It's very nicely written (prose-wise) for a technical book (the introduction in particular is lovely), but the pacing and subject matter chosen don't really work for most people afaics
I found it confusing from the perspective of a beginner and had a feeling of discontentment as an intermediate. Though some topics were elaborately expounded but some were vague or confusing.