I'm reading the book "JavaScript Notes For Professionals" (free download from this website: https://books.goalkicker.com/JavaScriptBook/). At [chapter 40, page 251: Unary Operators] it says:

Unary operators are more efficient than standard JavaScript function calls

Being as ignorant as I am, I don't quite understand in which way is it more efficient. Are unary operators more performant, or just simply more readable?