I’m not new to programming languages, but I am (was) new to JavaScript. If you’re looking for a great reference resource, my (strong) recommendation is:
JavaScript The Definitive Guide, Seventh Edition by David Flanagan. Published by O’Reilly.
https://www.amazon.com/gp/product/1491952024
Note: I have no affiliation with Mr. Flanagan or O’Reilly publishing. It’s just been an extremely helpful book. It answers 98% of my questions so I don’t have to post them here on our NSB community blog unless it’s truly about NSB/AppStudio (not the core workings of JavaScript, browsers, and plugins).