What is === in javascript?

The operator ~ returns that result:

~N = -(N+1)

But this is an effect of inverting the value of all bits of a variable.

Double tilde ~~ is used to convert some types to int, since ~ operator converts the value to a 32-bit int before inverting its bits. Thus:

~~'-1' = -1
~~true = 1
~~false = 0
~~5.6 = 5