I have definitely used the +!! "operator" before. It coerces a value into a boolean integer. It's not weird at all, just a mechanical application of the not ! a

I have definitely used the +!! "operator" before. It coerces a value into a boolean integer. It's not weird at all, just a mechanical application of the not ! and Number coercion operators +. The fact that [] is truthy is something everybody learns in their first weeks of JS programming otherwise you would be writing `if (someArray)` and wondering why your code is broken. A weird one would be to explain why +[] is 0 and +{} is NaN. That is nonsensical.