Frameworks change very often in JS land. Understanding the fundamentals of a language very well will give you a great productivity boost even if you're writing Angular/Backbone/Knockout/Aurelia/React/Flux/JSMVC/whatever_framework code all day.
This book isn't about the edge cases of how `==` works or how `>` works when comparing objects of different types. It's about the fundamentals of the language and the idioms and how to write effective code using them.
If you already know JS very well you can skip it or skim it - but if you're a 'framework developer' as a reader I guarantee that it will be worth your time. If your JS is already very good - you might want to consider spending your time learning another language or technology rather than being "more great" at JS unless you want to get involved in the specification process.
This book isn't about the edge cases of how `==` works or how `>` works when comparing objects of different types. It's about the fundamentals of the language and the idioms and how to write effective code using them.
If you already know JS very well you can skip it or skim it - but if you're a 'framework developer' as a reader I guarantee that it will be worth your time. If your JS is already very good - you might want to consider spending your time learning another language or technology rather than being "more great" at JS unless you want to get involved in the specification process.