operators - What does the '!!!' syntax mean in javascript?

Question

I just came across the following line of code in one of the Windows Store Apps samples.

if (that.assets[asset].object === null || !!!that.assets[asset].object.canPlayType) {

It uses a triple exclamation mark syntax. I've done some testing (and I'm pretty sure I missed something), and the result is always the same a single !. I assumed it was somewhat equivalent to === and !==...

Can anyone explain what the !!! syntax means?

Answer 1

I assumed it was somewhat equivalent to === and !==...

No, it's just three "not" operators, a "not-not-not".

It's the same as !(!(!(x))), and is always equivalent to a single !x.

There is literally no use for this. !! is a somewhat cryptic means of converting any variable to its boolean representation, but !!! is just silly. You can chain an arbitrary number of !'s together, but it isn't useful for anything.