Representative Line: Greater Than False

Today's anonymous submitter passes us a single line of JavaScript, and it's a doozy. This line works, but that's through no fault of the developer behind it.

{arr?.length && shouldNotShow === false > 0 (...)}

Pedantically, this is JSX, not pure JavaScript, but the rules still apply.

So, fun fact in JavaScript: true > 0 is true, and false > 0 is false. Which generally makes sense, but why would you use that here? But this code is worse than it looks, thanks to operator precedence.

The highest precedence operation is the optional chain- arr?.length. The second highest operation? >. So the first part of the comparison that evaluates is false > 0. Which is false. Do you know what's next? ===. So we compare shouldNotShow to false. Then we && that with the potentially falsy value from our arr?.length.

It's all a mess, and it's all so we can compare against false, which we could have just done with a ! operator. !(arr?.length && shouldNotShow).

Our submitter credits this to an offshore team, and this does have the vibe of throwing characters at the problem until it passes the test. Less LLM-guided and more "manually executed Markov chain". That's also an accurate description of the rest of the code in this code base: hand crafted Markov chain generation.

This post originally appeared on The Daily WTF.