Can someone explain to me why I would need something like this over just hand rolling my own validation? Almost every time I've seen one of these JS validation libraries used, it was to verify a form with < 10 inputs and every one of those validations were no more complex than `isNonEmptyString = (x: string | undefined) => x != null && x.trim() != "")` or `isGtZero = (x: any): !isNaN(parseInt(x, 10)) && parseInt(x, 10) > 0`

This feels about as trivial as an aggregate package of `isOdd` / `isArray` absurd micropackages. Surely I must be missing something because they're incredibly popular?