Which is why I only use it on solo projects.

That being said, ~indexOf is hardly tricky. if(string.indexOf(term)) is far trickier, because if you didn't realize it returning 0 was a positive result, you easily could write it without a -1 check and not notice it during testing if no values had an index of 0. Then months later you would have a hell of a time debugging it because it would look so innocuous.

On the other hand, by including the tilde, you ensure two things: 1.) Future developer knows what it does and has no problems. 2.) Future developer hasn't seen it before and goes straight to google to see what it does - at which point they learn and now will recognize it in the future.

So at the end of the day, by using a ~, it is explicitly clear that indexOf() should not be used directly as a coerced boolean, and it ensures that anyone touching the code will either know or learn why.

If you come from a C background you would probably parse the intent of that immediately. Bitwise complement is pretty basic stuff and is probably what the C compiler winds up optimizing `!<int>` to anyway. I'm guessing that the only reason it's used here is character optimization.