If you are new to JavaScript or want to refresh you knowledge with the latest and greatest that is inside the language, I can only recommend to spend some time with the 4th edition of Marijn Haverbeke's book; Eloquent JavaScript.
I’ve read it during the weekend and I have to admit that it revived my interest(love?) in the language. After spending most of my time using C# and TypeScript it is great to see how far we can get with modern JavaScript.
The book is well written with a lot of examples, handling both basic and more advanced feature of the language. It includes some (small) projects that are fun to build and try and allow you to apply the knowledge you’ve acquired.
So if you want to learn how to write ‘modern’ JavaScript, this is a must read!