We can use ~ as a shorthand in some everyday scenarios.
We know that ~ converts -1 to 0, so we can use it with indexOf on array.
indexOf
let items = ['foo', 'bar', 'baz'];
let el = 'a';
if (items.indexOf('a') !== -1) {}
or
if (items.indexOf('a') >= 0) {}
can be re-written as
if (...