I think doing that is highly resource hungry and should be avoided

!! is used to convert a truthy/falsy value to its boolean equivalent.

let num = 5; (truthy)
!num // false
!!num // true

let num = 0; (falsy)
!num // true
!!num // false

comparing 5 with !!5 would be the equivalent of comparing 5 with true (which is false)
5 === !!5
5 === true

The only reason people still use it over Boolean (other than wanting to look like elite hackers) is because it's something like 10-15% faster (last time I checked)

If you mean the sample tests, you need to write your own, otherwise, click Attempt directly.

yea, you can have as many as you want, tho it becames quite unreadable after a certain depth...

That's not a ternary, those are two.