Troy Miles wrote jQuery Essentials published by Packt Publishing 2016. This is a good enough book that twice I started a review of it. The code for this book is available to download on packtpub.com
The book has good coverage of the DOM, document object model. I like the section in chapter9 about never modify the DOM in a loop.
Chapter 8 about separation of concerns covers unit tests. Tells you how to use events to decouple code. Break the code into logical units. Separation of Concerns is a useful software architecture pattern.
The book covers key fundamentals of jQuery