What does 'x << ~y' represent in JavaScript?

Question

What does \'x << ~y\' represent in JavaScript?

I understand that the bitwise SHIFT operation does this:

x << y AS x * 2y         


        

Answer 1

5 << ~3 gives the same result as 5 << -4, you are right.

Important thing: shifting x << y really results into x * 2^y, but it is not a direct usage, it is just a useful side-effect.
Moreover, if you have a negative y, it doesn't work in the same way.